A study published in the current issue of the New England Journal of Medicine reports that the smoking ban in Scotland resulted in a 17% decline in hospital admissions for acute coronary syndrome (including myocardial infarctions [heart attacks] and unstable angina) (see : Pell JP et al. Smoke-free legislation and hospitalizations for acute coronary syndrome. N Engl J Med 2008; 359:482-491).
The study compared the number of admissions for acute coronary syndrome in nine hospitals in Scotland (representing 63% of admissions for acute coronary syndrome in the country) during the 10-month period prior to the smoking ban and the corresponding 10-month period the following year. The number of admissions declined from 3235 to 2684, a drop of 17%.
This 17% drop was compared to the trend in overall hospital admissions in all of Scotland during the preceding 10 years. According to the study, "the trend during the 10 years before legislation was a 3% mean annual reduction, with a maximum reduction of 9% in 2000."
Because the observed 17% reduction in admissions for acute coronary syndrome was much higher than the annual reduction during the 10 previous years and exceeded the highest annual decline between any two years, the study concludes that the observed reduction is attributable to the smoking ban.
The Rest of the Story
The problem with this article is that its conclusion is based on a comparison of apples to oranges. In order to compare the change in heart attacks in Scotland from 2006-2007 to the trend in heart attacks during the preceding ten-year period, one needs to use the same data source to compare these trends.
In this article, the researchers use one source of data to estimate the change in heart attacks from 2006-2007 (observed changes in admissions for nine hospitals representing a portion of the country) and a different source of data to estimate the trend in heart attacks from 1996-2006 (national data from the Scottish National Health Service).
A critical basis for the article's conclusion is that the year-to-year decline in heart attacks in Scotland never exceeded 10%, while the researchers found a 17% decline in heart attacks during the year following the smoking ban.
However, the relevant question is not what the national health service data show, but what changes in heart attack admissions would have been found using the same methods employed by the researchers to count heart attack admissions for 2006-2007. What would the annual changes have been using the same 9 hospitals and using the same method of counting heart attack admissions?
It is important to note that:
(1) The diagnosis of acute coronary syndrome in 2006-2007 was based on an assay for cardiac troponin (a component of cardiac muscle which is released into the blood following heart injury), which is a very sensitive test for cardiac injury. For the period 1996-2006, the diagnosis was likely made based on less sensitive measures, since the use of troponin to diagnose coronary syndrome has greatly increased in recent years.
(2) The random variation and secular trends in coronary syndrome for the 10-year period prior to the smoking ban are based on standardized, national data which include the entire country of Scotland. Thus, the variation is likely to be much lower than the variation in the data from a sample of just 9 hospitals.
The correct way to conduct this analysis would be to examine the trends in heart attacks in all of Scotland for the entire ten-year period using a single, standardized and consistent data source and then to examine the degree of random variation in year-to-year changes in heart attacks and see if the observed change associated with the smoking ban is inconsistent with the magnitude of observed year-to-year changes during the years preceding the smoking ban.
Fortunately, the annual data on heart attack admissions in Scotland is available online, so we can examine the magnitude of year-to-year changes in heart attacks in the past decade and see how the change associated with the smoking ban compares.
Remember that the smoking ban was implemented in March 2006, so changes from 2005 to 2006 would reflect the smoking ban, as would changes from 2006 to 2007.
Between 2005 and 2006, the number of heart attack admissions in all of Scotland declined by 4.2%. Between 2006 and 2007, the number of heart attack admissions in Scotland dropped by 8.0%.
That might sound like a big drop, large enough that we would conclude it was due to the smoking ban.
However, look at the year-to-year declines in heart attacks in Scotland in years prior to the smoking ban.
Between 2003 and 2004, heart attack admissions declined by 4.6%. This is greater than the observed heart attack decline from 2005 to 2006.
Between 1999 and 2000, heart attack admissions in Scotland declined by 10.2%. This is much greater than even the 8.0% decline observed from 2006 to 2007.
Even if we look at the 2-year decline in heart attacks from 2005 to 2007, it is about the same as the 2-year decline observed bewteen 1999 and 2001 (11.9% compared to 10.7%).
If I present the data this way, it makes it clear that the observed change in heart attacks associated with the smoking ban is not at all out of the range of normal declines in heart attacks from year to year in Scotland observed in the absence of the smoking ban.
2005-2006: -4.2% 2003-2004: -4.6%
2006-2007: -8.0% 1999-2000: -10.2%
My point here is not that these data prove there was no decline in heart attacks in Scotland attributable to the smoking ban. My point is merely that there is no way one can conclude that the observed decline in the year following the smoking ban was different from the magnitude of the declines observed in previous years.
The analysis in this paper assumes that the entire observed change in heart attacks is attributable to the smoking ban. However, it is clear that a 10.2% decline in Scotland from 1999-2000 occurred in the complete absence of a smoking ban. Clearly, there are other factors which are contributing to a decline in heart attacks, there is a secular trend of substantially declining heart attacks over time, and in fact, the magnitude of the decline associated with the smoking ban is less than the magnitude of the decline observed in some recent years preceding the smoking ban.
In other words, one cannot rule out the very plausible alternative hypothesis that the observed decline in heart attacks is explained by random variation in the data and the already existing secular trend of declining heart attacks in Scotland.
Showing posts sorted by relevance for query apples to oranges. Sort by date Show all posts
Showing posts sorted by relevance for query apples to oranges. Sort by date Show all posts
Thursday, July 31, 2008
Monday, December 01, 2008
Data Released by Scottish National Health Service Show that Conclusions of Earlier Study about Effect of Smoking Ban on Heart Attacks Were Wrong
Data from the Scottish National Health Service on hospital admissions for heart attacks and unstable angina (acute coronary syndrome) obtained and released by Christopher Snowdon over at Velvet Glove Iron Fist reveal that admissions for acute coronary syndrome rose sharply during the second year of the smoking ban, such that there was little overall change over the first two years during which the smoking ban has been in effect.
This demonstrates that the decline in acute coronary syndrome admissions observed during the first year after the smoking ban was not due to the ban, but was simply a reflection of underlying variation in the data -- it is apparent now that the decline was just a blip down and the admissions have now climbed back up to where they were prior to the smoking ban.
As Snowdon writes: "Much was made of an apparent reduction in the number of patients being diagnosed with the life-threatening heart condition after the smoking ban came into effect in 2006, including a study published in the New England Journal of Medicine which claimed that the ban had caused emergency ACS [acute coronary sydrome] admissions to fall by 17%."
"However, official statistics show that the decline in hospitals admissions for acute coronary syndrome has been greatly exaggerated. The real decline in the first year of the smoking ban was just 7.2% - not 17% - and the rate then rose by 7.8% in the second year, cancelling out the earlier drop."
"In the last 12 months before Scotland enacted its smoking ban (April 05 to March 06) there were 16,199 admissions for acute coronary syndrome*. In the second year of the smoking ban (April 07 to March 08) there were 16,212 admissions, slightly more than there had been before the legislation was enacted." ...
"Hospital admissions for acute coronary syndrome have been declining in Scotland for many years. The new data show that the well-publicised fall in admissions following Scotland's smoke-free legislation was in line with the existing downward trend and was significantly less steep than has previously been claimed."
"The belief that the number of cases of acute coronary syndrome fell by 17% after the smoking ban stems from a study of volunteers in a selection of Scottish hospitals between 2005 and 2007. The study - 'Smoke-free Legislation and Hospitalizations for Acute Coronary Syndrome' - has since been criticised for its limited scope and for excluding data from several key months before and after the ban."
"If the 2006-07 decline had really been the result of the smoke-free legislation, it would be expected for rates to remain low in subsequent years. The fact that Scottish hospitals have seen an unusually sharp rise - despite the smoking ban being rigorously enforced - suggests that whatever lay behind the 2006-07 dip, it was not the smoking ban."
The Whole Story
In September 2007, the University of Glasgow issued a press release announcing a new study which concluded that the smoking ban in Scotland had resulted in a 17% decline in heart attack admissions during the first year in which the smoking ban was in effect. The University of Glasgow is the home of the lead researcher on the study: Dr. Jill Pell. The study itself was not made available. However, its conclusions were blasted throughout the world via the media.
For example, in an uncritical recounting of the data and conclusions in the press release, Spiegel wrote as follows:
"it seems a miracle has happened: The number of heart attacks in Scotland has suddenly dropped by no less than 17 percent in a single year. What has happened? Have the Scots stopped eating red meat? Has the whole country started knocking back cholesterol medication? Are they all training for the marathon? No. The reason is much simpler: Scots are having fewer heart attacks because they are no longer inhaling other people's cigarette smoke when they sit in the pub, the train or the office."
According to the press release: "A University of Glasgow study has found a 17 per cent fall in admissions for heart attacks in the first year after the smoking ban came into force. The evaluation, led by Professor Jill Pell from the University’s BHF Cardiovascular Research Centre, found that after the legislation came into force there was a 17 per cent reduction in heart attack admissions to the hospitals. This compares with an annual reduction in Scottish admissions for heart attack of 3 per cent per year in the decade before the ban."
At the time, I criticized the study for two reasons. First, I argued that the release of the study via a press release represented a "science by press release" approach that was not appropriate, because study conclusions should not be disseminated through the media until after they have undergone peer review and the study has been published, or at least until researchers are willing to make the entire study and its methodology available so that it can be reviewed by others.
I also criticized the study conclusions because it was not clear that the reported decline in heart attacks was not simply random variation and/or an existing secular decline in heart attacks that was occurring anyway, even without the smoking ban.
I noted: "To see why a thorough review of the actual study is necessary, just look at the hospital discharge data for heart attacks in Scotland. We find evidence of a large single-year decline in heart attacks of about 10% which occurred in the absence of any smoking ban. This indicates that there can be a large year-to-year variation in heart attacks in Scotland and makes it especially difficult to determine whether a 17% annual decline in heart attacks is due in part to random variation, and if so, to what extent. From the information that was provided to us, it is impossible to conclude that the smoking ban was responsible for the observed decline in heart attack admissions.
It is also important to consider the fact that the more rapid decline in heart attack admissions in Scotland appears to have begun prior to the smoking ban. A drop in heart attack admissions of 17% (equal to what was observed after the smoking ban) actually occurred during the three-month period immediately prior to the smoking ban. It would be very questionable to attribute the observed heart attack decline to the smoking ban in the face of this evidence that heart attacks were declining substantially prior to the ban. It is entirely possible that some other factor is responsible for the observed decline."
Importantly, about two months after the initial press release, I discussed data, reported in an article by Michael Blastland published by the BBC News, that were released by the National Health Service's Informational Services Division. These data included all hospital admissions for heart attacks nationwide in Scotland, reported as annual standardized rates. The data showed a decline of about 8% in the year following the smoking ban, which is only slightly higher than the approximate 6% decline the year preceding the smoking ban. If one looked at the trend in heart attack rates from 1998 through 2007, one would find that based on the pre-existing trends in heart attack rates, there had been no apparent change in the rate of heart attacks following the smoking ban, which was implemented in March 2006.
In addition, these data confirmed an earlier analysis, in which I pointed out that a huge decline in heart attacks in Scotland from 1999 to 2000 occurred prior to the smoking ban and revealed the large degree of baseline variability in the data, meaning that only a junk science study would conclude that the observed decline in heart attacks during the 10 months following the smoking ban was attributable to the smoking ban. In fact, the data revealed that the largest drop in heart attack admission rates occurred not following the smoking ban, but from 1999 to 2000.
Despite the shoddy nature of the study's conclusions and the unsupporting data coming from a national, population-based database, the authors proceeded to publish their study in the New England Journal of Medicine in July, 2008. The study concluded that the smoking ban in Scotland resulted in a 17% decline in hospital admissions for acute coronary syndrome (including myocardial infarctions [heart attacks] and unstable angina) (see : Pell JP et al. Smoke-free legislation and hospitalizations for acute coronary syndrome. N Engl J Med 2008; 359:482-491).
The study compared the number of admissions for acute coronary syndrome in nine hospitals in Scotland (representing 63% of admissions for acute coronary syndrome in the country) during the 10-month period prior to the smoking ban and the corresponding 10-month period the following year. The number of admissions declined from 3235 to 2684, a drop of 17%.
This 17% drop was compared to the trend in overall hospital admissions in all of Scotland during the preceding 10 years. According to the study, "the trend during the 10 years before legislation was a 3% mean annual reduction, with a maximum reduction of 9% in 2000."
Because the observed 17% reduction in admissions for acute coronary syndrome was much higher than the annual reduction during the 10 previous years and exceeded the highest annual decline between any two years, the study concludes that the observed reduction is attributable to the smoking ban.
I immediately argued that: "The problem with this article is that its conclusion is based on a comparison of apples to oranges. In order to compare the change in heart attacks in Scotland from 2006-2007 to the trend in heart attacks during the preceding ten-year period, one needs to use the same data source to compare these trends. In this article, the researchers use one source of data to estimate the change in heart attacks from 2006-2007 (observed changes in admissions for nine hospitals representing a portion of the country) and a different source of data to estimate the trend in heart attacks from 1996-2006 (national data from the Scottish National Health Service)." I argued that this is comparing apples to oranges, and it is not valid science.
In September 2008, Christopher Snowdon over at Velvet Glove Iron Fist reported that the results and conclusions of the Pell et al. study were wrong. Snowdon's article was based on a complete data set of acute coronary syndrome admissions in all of Scotland for the entire period from 1999 through 2007. He included data for the full two years following the smoking ban and for at least seven years preceding the ban. Snowdon found that contrary to the results reported by Pell et al., acute coronary syndrome admissions fell by just 9.3% in the year following the ban (compared to the year preceding the ban). But more importantly, this decline was no greater than that observed several times during the baseline period. For example: "AMI [acute myocardial infarction] admissions fell by 10.2% in 1999-2000 and angina admissions fell by 10.5% in 2005-2006 (there were also falls of 11.6%, 11% and 12% in previous years)."
Moreover, when one examined the full data, one saw that while there was a decline in acute coronary syndrome admissions in Scotland following the smoking ban, this decline was not as steep as it had been prior to the smoking ban. In other words, the rate of decline in acute coronary syndrome admissions actually decreased after the smoking ban.
Now, the data obtained by Christopher Snowdon reveal that what happened in Scotland was the opposite of what the researchers reported. Rather than to create an acceleration in the existing rate of decline in acute coronary syndrome admissions, the implementation of the smoking ban was associated with a decrease in the rate of decline. In fact, in the two years that the smoking ban has been in effect, the trend of declining acute coronary syndrome admissions in Scotland has ground to a halt.
This does not, of course, mean that the smoking ban resulted in an increase in heart attacks. It simply demonstrates that the observed decline in acute coronary syndrome admissions was a statistical blip. Data tends to zig and zag just from normal random variation. If you catch the data when it is zagging, you might inadvertently conclude that heart attacks are dropping, unless you stick around long enough to see that the next year, the heart attack rate zigs.
The zigging and zagging of statistical data is normal. What science must do is to account for this zigging and zagging and refrain from drawing conclusions about changes in data until the underlying zigging and zagging has been accounted for. This is what the authors of the Scottish smoking ban study failed to do.
And now, the most complete data yet assembled show that the conclusion of their New England Journal of Medicine study was wrong: the smoking ban in Scotland did not cause a substantial, immediate drop in heart attacks or acute coronary syndrome.
The Rest of the Story
There are three important parts to the rest of the story.
First, this story demonstrates the dangers of science by press release. The conclusions from the Scotland smoking ban study have already been disseminated widely to the public and it is far too late to retract them. Even if the researchers were to issue a media advisory in which they noted that their conclusion has been disproved, it is unlikely that it would pick up enough media attention to undo the publicity created by the initial media coverage.
Second, this story demonstrates the significant bias inherent in research by the anti-smoking movement these days. This bias is so strong that researchers can apparently not wait until they have sufficient data to draw a reasonable conclusion. The desired conclusion has to be disseminated widely when it is still preliminary in order to create a media splash that cannot be reversed if the conclusions subsequently prove to be wrong.
Third, this story demonstrates that the anti-smoking movement does not really care about the truth: it cares mostly about producing favorable evidence to support its conclusions. When the original studies came out (both the unpublished study and the published article), anti-smoking groups issued press releases and did everything they could to generate media attention about the study conclusions. Now that these conclusions have proven to be wrong, anti-smoking groups are not publicizing the error of the study. They are not issuing press releases to report these new data and to update the public with the accurate conclusion of the study. Nor are they going to do so.
I will go through the usual motions of disseminating my commentary throughout the movement, to all the key groups which have issued what turns out to be false, preliminary conclusions. But these groups are not going to do anything to correct the damage that has been done through the dissemination of these inaccurate conclusions.
You see - it doesn't really matter anyway. This is the tobacco control movement and since it is all for a good cause, there really isn't damage done by disseminating false scientific conclusions. Thus, it doesn't need to be corrected. After all, this is no longer about scientific accuracy or scientific integrity. This isn't about the truth. It's about producing favorable evidence to support the policy agenda of the anti-smoking movement.
This demonstrates that the decline in acute coronary syndrome admissions observed during the first year after the smoking ban was not due to the ban, but was simply a reflection of underlying variation in the data -- it is apparent now that the decline was just a blip down and the admissions have now climbed back up to where they were prior to the smoking ban.
As Snowdon writes: "Much was made of an apparent reduction in the number of patients being diagnosed with the life-threatening heart condition after the smoking ban came into effect in 2006, including a study published in the New England Journal of Medicine which claimed that the ban had caused emergency ACS [acute coronary sydrome] admissions to fall by 17%."
"However, official statistics show that the decline in hospitals admissions for acute coronary syndrome has been greatly exaggerated. The real decline in the first year of the smoking ban was just 7.2% - not 17% - and the rate then rose by 7.8% in the second year, cancelling out the earlier drop."
"In the last 12 months before Scotland enacted its smoking ban (April 05 to March 06) there were 16,199 admissions for acute coronary syndrome*. In the second year of the smoking ban (April 07 to March 08) there were 16,212 admissions, slightly more than there had been before the legislation was enacted." ...
"Hospital admissions for acute coronary syndrome have been declining in Scotland for many years. The new data show that the well-publicised fall in admissions following Scotland's smoke-free legislation was in line with the existing downward trend and was significantly less steep than has previously been claimed."
"The belief that the number of cases of acute coronary syndrome fell by 17% after the smoking ban stems from a study of volunteers in a selection of Scottish hospitals between 2005 and 2007. The study - 'Smoke-free Legislation and Hospitalizations for Acute Coronary Syndrome' - has since been criticised for its limited scope and for excluding data from several key months before and after the ban."
"If the 2006-07 decline had really been the result of the smoke-free legislation, it would be expected for rates to remain low in subsequent years. The fact that Scottish hospitals have seen an unusually sharp rise - despite the smoking ban being rigorously enforced - suggests that whatever lay behind the 2006-07 dip, it was not the smoking ban."
The Whole Story
In September 2007, the University of Glasgow issued a press release announcing a new study which concluded that the smoking ban in Scotland had resulted in a 17% decline in heart attack admissions during the first year in which the smoking ban was in effect. The University of Glasgow is the home of the lead researcher on the study: Dr. Jill Pell. The study itself was not made available. However, its conclusions were blasted throughout the world via the media.
For example, in an uncritical recounting of the data and conclusions in the press release, Spiegel wrote as follows:
"it seems a miracle has happened: The number of heart attacks in Scotland has suddenly dropped by no less than 17 percent in a single year. What has happened? Have the Scots stopped eating red meat? Has the whole country started knocking back cholesterol medication? Are they all training for the marathon? No. The reason is much simpler: Scots are having fewer heart attacks because they are no longer inhaling other people's cigarette smoke when they sit in the pub, the train or the office."
According to the press release: "A University of Glasgow study has found a 17 per cent fall in admissions for heart attacks in the first year after the smoking ban came into force. The evaluation, led by Professor Jill Pell from the University’s BHF Cardiovascular Research Centre, found that after the legislation came into force there was a 17 per cent reduction in heart attack admissions to the hospitals. This compares with an annual reduction in Scottish admissions for heart attack of 3 per cent per year in the decade before the ban."
At the time, I criticized the study for two reasons. First, I argued that the release of the study via a press release represented a "science by press release" approach that was not appropriate, because study conclusions should not be disseminated through the media until after they have undergone peer review and the study has been published, or at least until researchers are willing to make the entire study and its methodology available so that it can be reviewed by others.
I also criticized the study conclusions because it was not clear that the reported decline in heart attacks was not simply random variation and/or an existing secular decline in heart attacks that was occurring anyway, even without the smoking ban.
I noted: "To see why a thorough review of the actual study is necessary, just look at the hospital discharge data for heart attacks in Scotland. We find evidence of a large single-year decline in heart attacks of about 10% which occurred in the absence of any smoking ban. This indicates that there can be a large year-to-year variation in heart attacks in Scotland and makes it especially difficult to determine whether a 17% annual decline in heart attacks is due in part to random variation, and if so, to what extent. From the information that was provided to us, it is impossible to conclude that the smoking ban was responsible for the observed decline in heart attack admissions.
It is also important to consider the fact that the more rapid decline in heart attack admissions in Scotland appears to have begun prior to the smoking ban. A drop in heart attack admissions of 17% (equal to what was observed after the smoking ban) actually occurred during the three-month period immediately prior to the smoking ban. It would be very questionable to attribute the observed heart attack decline to the smoking ban in the face of this evidence that heart attacks were declining substantially prior to the ban. It is entirely possible that some other factor is responsible for the observed decline."
Importantly, about two months after the initial press release, I discussed data, reported in an article by Michael Blastland published by the BBC News, that were released by the National Health Service's Informational Services Division. These data included all hospital admissions for heart attacks nationwide in Scotland, reported as annual standardized rates. The data showed a decline of about 8% in the year following the smoking ban, which is only slightly higher than the approximate 6% decline the year preceding the smoking ban. If one looked at the trend in heart attack rates from 1998 through 2007, one would find that based on the pre-existing trends in heart attack rates, there had been no apparent change in the rate of heart attacks following the smoking ban, which was implemented in March 2006.
In addition, these data confirmed an earlier analysis, in which I pointed out that a huge decline in heart attacks in Scotland from 1999 to 2000 occurred prior to the smoking ban and revealed the large degree of baseline variability in the data, meaning that only a junk science study would conclude that the observed decline in heart attacks during the 10 months following the smoking ban was attributable to the smoking ban. In fact, the data revealed that the largest drop in heart attack admission rates occurred not following the smoking ban, but from 1999 to 2000.
Despite the shoddy nature of the study's conclusions and the unsupporting data coming from a national, population-based database, the authors proceeded to publish their study in the New England Journal of Medicine in July, 2008. The study concluded that the smoking ban in Scotland resulted in a 17% decline in hospital admissions for acute coronary syndrome (including myocardial infarctions [heart attacks] and unstable angina) (see : Pell JP et al. Smoke-free legislation and hospitalizations for acute coronary syndrome. N Engl J Med 2008; 359:482-491).
The study compared the number of admissions for acute coronary syndrome in nine hospitals in Scotland (representing 63% of admissions for acute coronary syndrome in the country) during the 10-month period prior to the smoking ban and the corresponding 10-month period the following year. The number of admissions declined from 3235 to 2684, a drop of 17%.
This 17% drop was compared to the trend in overall hospital admissions in all of Scotland during the preceding 10 years. According to the study, "the trend during the 10 years before legislation was a 3% mean annual reduction, with a maximum reduction of 9% in 2000."
Because the observed 17% reduction in admissions for acute coronary syndrome was much higher than the annual reduction during the 10 previous years and exceeded the highest annual decline between any two years, the study concludes that the observed reduction is attributable to the smoking ban.
I immediately argued that: "The problem with this article is that its conclusion is based on a comparison of apples to oranges. In order to compare the change in heart attacks in Scotland from 2006-2007 to the trend in heart attacks during the preceding ten-year period, one needs to use the same data source to compare these trends. In this article, the researchers use one source of data to estimate the change in heart attacks from 2006-2007 (observed changes in admissions for nine hospitals representing a portion of the country) and a different source of data to estimate the trend in heart attacks from 1996-2006 (national data from the Scottish National Health Service)." I argued that this is comparing apples to oranges, and it is not valid science.
In September 2008, Christopher Snowdon over at Velvet Glove Iron Fist reported that the results and conclusions of the Pell et al. study were wrong. Snowdon's article was based on a complete data set of acute coronary syndrome admissions in all of Scotland for the entire period from 1999 through 2007. He included data for the full two years following the smoking ban and for at least seven years preceding the ban. Snowdon found that contrary to the results reported by Pell et al., acute coronary syndrome admissions fell by just 9.3% in the year following the ban (compared to the year preceding the ban). But more importantly, this decline was no greater than that observed several times during the baseline period. For example: "AMI [acute myocardial infarction] admissions fell by 10.2% in 1999-2000 and angina admissions fell by 10.5% in 2005-2006 (there were also falls of 11.6%, 11% and 12% in previous years)."
Moreover, when one examined the full data, one saw that while there was a decline in acute coronary syndrome admissions in Scotland following the smoking ban, this decline was not as steep as it had been prior to the smoking ban. In other words, the rate of decline in acute coronary syndrome admissions actually decreased after the smoking ban.
Now, the data obtained by Christopher Snowdon reveal that what happened in Scotland was the opposite of what the researchers reported. Rather than to create an acceleration in the existing rate of decline in acute coronary syndrome admissions, the implementation of the smoking ban was associated with a decrease in the rate of decline. In fact, in the two years that the smoking ban has been in effect, the trend of declining acute coronary syndrome admissions in Scotland has ground to a halt.
This does not, of course, mean that the smoking ban resulted in an increase in heart attacks. It simply demonstrates that the observed decline in acute coronary syndrome admissions was a statistical blip. Data tends to zig and zag just from normal random variation. If you catch the data when it is zagging, you might inadvertently conclude that heart attacks are dropping, unless you stick around long enough to see that the next year, the heart attack rate zigs.
The zigging and zagging of statistical data is normal. What science must do is to account for this zigging and zagging and refrain from drawing conclusions about changes in data until the underlying zigging and zagging has been accounted for. This is what the authors of the Scottish smoking ban study failed to do.
And now, the most complete data yet assembled show that the conclusion of their New England Journal of Medicine study was wrong: the smoking ban in Scotland did not cause a substantial, immediate drop in heart attacks or acute coronary syndrome.
The Rest of the Story
There are three important parts to the rest of the story.
First, this story demonstrates the dangers of science by press release. The conclusions from the Scotland smoking ban study have already been disseminated widely to the public and it is far too late to retract them. Even if the researchers were to issue a media advisory in which they noted that their conclusion has been disproved, it is unlikely that it would pick up enough media attention to undo the publicity created by the initial media coverage.
Second, this story demonstrates the significant bias inherent in research by the anti-smoking movement these days. This bias is so strong that researchers can apparently not wait until they have sufficient data to draw a reasonable conclusion. The desired conclusion has to be disseminated widely when it is still preliminary in order to create a media splash that cannot be reversed if the conclusions subsequently prove to be wrong.
Third, this story demonstrates that the anti-smoking movement does not really care about the truth: it cares mostly about producing favorable evidence to support its conclusions. When the original studies came out (both the unpublished study and the published article), anti-smoking groups issued press releases and did everything they could to generate media attention about the study conclusions. Now that these conclusions have proven to be wrong, anti-smoking groups are not publicizing the error of the study. They are not issuing press releases to report these new data and to update the public with the accurate conclusion of the study. Nor are they going to do so.
I will go through the usual motions of disseminating my commentary throughout the movement, to all the key groups which have issued what turns out to be false, preliminary conclusions. But these groups are not going to do anything to correct the damage that has been done through the dissemination of these inaccurate conclusions.
You see - it doesn't really matter anyway. This is the tobacco control movement and since it is all for a good cause, there really isn't damage done by disseminating false scientific conclusions. Thus, it doesn't need to be corrected. After all, this is no longer about scientific accuracy or scientific integrity. This isn't about the truth. It's about producing favorable evidence to support the policy agenda of the anti-smoking movement.
Monday, February 09, 2009
ASH-UK Compares Critics of Link Between Smoking Bans and Dramatic Heart Attack Reductions to AIDS Dissidents Who Deny Link Between HIV and AIDS
In an article published this month online ahead of print in the journal Expert Review of Pharmacoeconomics and Outcomes Research, Martin Dockrell - policy and campaigns manager for Action on Smoking and Health in London (ASH-UK) - argues that those who have questioned the causal relationship between smoking bans and dramatic, immediate reductions in heart attacks are comparable to dissidents who deny the causal link between the HIV virus and AIDS (see: Dockrell M. Eye and heart at mortal war: coronaries and controversy in a smoke-free Scotland. Expert Review of Pharmacoeconomics and Outcomes Research 2009).
Dockrell argues that the Pell et al. study, which reported a 17% decline in acute coronary syndrome cases during the first year following the implementation of a smoking ban in Scotland, is conclusive evidence of a causal relationship between the smoking ban and a dramatic and immediate decline in acute cardiac events. He further argues that anyone who disagrees with this conclusion is a denialist, similar to the AIDS denialists, and that such opinion is an orchestrated artifact of tobacco industry lobbying, rather than sincere scientific criticism of the study conclusions.
Specifically, Dockrell argues that: "Organized groups who seek to deny and discredit this work are comparable in nature and intent, but not in origin, to the self-styled AIDS dissidents who continue to deny the causal link between HIV and AIDS and offer a comparable threat to an evidence-based health policy."
Moreover, Dockrell asserts that this dissidence is not pure: it is the result of orchestration by the tobacco industry: "While AIDS dissidence was largely an indigenous phenomenon, tobacco dissidence is the carefully conceived creature of tobacco industry lobbyists."
Readers should keep in mind that I am in fact a major dissenter, as I have criticized the Pell et al. study (critique 1; critique 2; critique 3; critique 4; critique 5; critique 6) and in fact have reported follow-up data which I believe demonstrate that the conclusion from that study was wrong. I have challenged anti-smoking groups to publicize the follow-up data which show that the decline in cardiac events during the first-year after Scotland's smoking ban was followed by an increase in cardiac events during the second year, thus disproving Pell et al.'s conclusion (post 1; post 2).
I take it this means that Dockrell is calling me a denialist and comparing me to AIDS dissidents who still deny that HIV causes AIDS. I also take it to mean that Dockrell is accusing me of being in the pocket of the tobacco companies and acting at their beck and call and presumably -their payments.
In fact, ASH-UK appears to make precisely such an accusation when it states in its press release to accompany the article: "A number of studies have been published recently showing a decline in admissions to hospital for heart attack following the implementation of smokefree laws in various countries. Many of these studies, including one on the impact of the Scottish smoking ban have also been the subject of criticism by so-called "dissidents" who claim that the research is nothing more than 'junk' science. In a recently published review ASH's Director of Policy and Research, Martin Dockrell, looks behind the scenes to see what has prompted this criticism and to what extent it is justified. The analysis finds parallels with those who were in denial about the causes of AIDS long after the scientific debate was over. ... We found an unholy alliance of conspiracy theorists, tobacco industry lobbyists and journalists impatient for a good story."
Dockrell is particularly critical of Michael Blastland, who wrote a commentary published by BBC News on November 14, 2007 which presented data showing that the actual decline in heart attacks in all of Scotland in the year following the smoking ban was similar to that observed in the three years preceding the ban, and that a dramatic decline in heart attacks occurred in 2000, in the absence of a smoking ban. Based on these findings, Blastland questioned the validity of the study's conclusion that the smoking ban was causally related to a 17% decline in acute cardiac events.
Dockrell argues in the article that Blastland is a denialist and conspiracy theorist and concludes that his criticism has been carefully conceived and orchestrated by the tobacco industry: "While AIDS dissidence was largely an indigenous phenomenon, tobacco dissidence is the carefully conceived creature of tobacco industry lobbyists."
The Rest of the Story
This article demonstrates the religious-like and McCarthyist-like nature of the modern-day anti-smoking movement. If you do not subscribe to the accepted dogma of the movement, even when there is legitimate scientific evidence that brings that dogma into question, you are a dissident and a denialist -- on no firmer ground than those who deny that AIDS is caused by the HIV virus. Moreover, you are not expressing a sincere opinion, but are in the pocket of the tobacco industry, part of an orchestrated industry campaign.
The absurdity of the article is evident in its implication that I - a strong anti-smoking advocate - am a denialist who is being orchestrated by the tobacco companies to disseminate conspiracy theories - since I myself have been a vocal critic of the conclusions of these heart attack/smoking ban studies.
Someone who has argued that secondhand smoke kills over 50,000 Americans each year and whose testimony about the tobacco industry's deception of the public contributed towards a $145 billion verdict against the companies is hardly someone who fits the description of being a denialist who is waving around conspiracy theories under orchestration by Big Tobacco.
To be sure, historically the tobacco industry has orchestrated campaigns to undermine the public's appreciation of the recognized hazards of active smoking and secondhand smoke exposure. If you want to read about that history, you need go only so far as to read my testimony in the Engle tobacco case, which initially resulted in a $145 billion verdict against the tobacco companies. It is also true that a number of supposedly independent scientists who have challenged the link between smoking or secondhand smoke and disease have been funded by the industry and have been part of a campaign orchestrated by the industry.
However, the criticism of the research linking smoking bans with a causal effect on acute cardiac events is largely a different story. First, the nature of the evidence is very different. While there is abundant evidence linking smoking and disease and one would have to be a denialist to argue that smoking is not harmful, the research being used to conclude that smoking bans result in huge, immediate declines in heart attacks is very weak. These conclusions are based on time trend analyses, often without a control group, they cannot adequately determine whether observed changes reflect random variation, secular trends, or a real effect of the smoking ban, and thus causal conclusions from these studies are very shaky.
I will not take the time here to explain all the methodologic weaknesses of these studies, but interested readers will find an extensive set of commentaries on my blog which critique this literature.
Perhaps the most important fact to point out here is that studies which have used national, population-based data for all of Scotland have failed to find a 17% decline in heart attacks in Scotland in the year after the smoking ban, and actually found that overall heart attack and angina admissions increased in the second year after the ban, thus negating the earlier decline. Overall, there was little change in heart attack admissions in all of Scotland from before the smoking ban to two years after the ban.
As Christopher Snowdon explained: "Much was made of an apparent reduction in the number of patients being diagnosed with the life-threatening heart condition after the smoking ban came into effect in 2006, including a study published in the New England Journal of Medicine which claimed that the ban had caused emergency ACS [acute coronary syndrome] admissions to fall by 17%. However, official statistics show that the decline in hospitals admissions for acute coronary syndrome has been greatly exaggerated. The real decline in the first year of the smoking ban was just 7.2% - not 17% - and the rate then rose by 7.8% in the second year, cancelling out the earlier drop."
"In the last 12 months before Scotland enacted its smoking ban (April 05 to March 06) there were 16,199 admissions for acute coronary syndrome. In the second year of the smoking ban (April 07 to March 08) there were 16,212 admissions, slightly more than there had been before the legislation was enacted." ...
"Hospital admissions for acute coronary syndrome have been declining in Scotland for many years. The new data show that the well-publicised fall in admissions following Scotland's smoke-free legislation was in line with the existing downward trend and was significantly less steep than has previously been claimed." ... "If the 2006-07 decline had really been the result of the smoke-free legislation, it would be expected for rates to remain low in subsequent years. The fact that Scottish hospitals have seen an unusually sharp rise - despite the smoking ban being rigorously enforced - suggests that whatever lay behind the 2006-07 dip, it was not the smoking ban."
Despite the accusation that Blastland is part of some tobacco-industry orchestrated campaign and that he nothing more than a denialist, Dockrell presents no evidence that either of these is the case. First, he fails to present any evidence showing that Blastland is being paid by Big Tobacco or that he has had any alliance, association, or communication with tobacco companies over his commentaries. Reading other articles written by Blastland, it appears that he is in fact not particularly focused on tobacco, but that he writes in general about many areas in which he believes that statistics have been inaccurately used to draw policy-relevant conclusions.
Second, Dockrell fails to present any evidence to suggest that Blastland's critiques of the smoking ban studies are anything other than legitimate scientific opinions. In fact, I find Blastland's commentary to be quite compelling and from a scientific standpoint, on much more solid ground than the Pell et al. article which was published in the New England Journal of Medicine.
The problem with the Pell et al. study is that its conclusion is based on a comparison of apples to oranges. In order to compare the change in heart attacks in Scotland from 2006-2007 to the trend in heart attacks during the preceding ten-year period, one needs to use the same data source to compare these trends. In the Pell et al. article, the researchers use one source of data to estimate the change in heart attacks from 2006-2007 (observed changes in admissions for nine hospitals representing a portion of the country) and a different source of data to estimate the trend in heart attacks from 1996-2006 (national data from the Scottish National Health Service).
A critical basis for the article's conclusion is that the year-to-year decline in heart attacks in Scotland never exceeded 10%, while the researchers found a 17% decline in heart attacks during the year following the smoking ban. However, the relevant question is not what the national health service data show, but what changes in heart attack admissions would have been found using the same methods employed by the researchers to count heart attack admissions for 2006-2007. What would the annual changes have been using the same 9 hospitals and using the same method of counting heart attack admissions?
In contrast, Blastland presents a consistent data source for hospital admissions throughout all of Scotland for a long period of time: 1998-2007. The graph he presents illustrates that there is no visible change in heart attacks in Scotland in 2006-2007. In fact, the graph shows that the rate of decline in heart attacks in Scotland remained exactly the same as it was prior to the smoking ban.
In addition, the graph shows that there was a substantial decline in heart attacks from 1999-2000 which occurred in the absence of a smoking ban, illustrating that the magnitude of decline in heart attacks in 2006-2007 is actually less than the random variation and secular trends in heart attacks that were observed in Scotland in prior years.
Thus, rather than being denialism, Blastland's criticism of the study is well-founded. Whether he is correct or not, there are absolutely no grounds to dismiss his criticism as being denialism, conspiracy theory, or tobacco industry propaganda being delivered by a paid hack, all of which are implied by Dockrell in his article and press release.
Action on Smoking and Health (UK) evidently views the anti-smoking movement as a religion. Any challenge to the doctrines of the religion amounts to heresy. Scientific discourse is not allowed. You have to accept everything anti-smoking researchers claim with blind faith.
ASH-UK would have the tobacco control movement turn into non-critical automatons, who merely accept, on blind faith, any research which is favorable to the cause. Science would no longer play a role. It would, in fact, become a religion rather than a science-based public health movement.
Moreover, Dockrell's article illustrates the McCarthyist nature of the modern day anti-smoking movement. If you challenge the doctrines of the movement, not only are you viewed as a denialist, but you are automatically attacked as being a Big Tobacco hack. In other words, without any evidence, you are publicly maligned in an attempt to permanently discredit you and blacklist you from any further participation in public discourse.
Dockrell has accused Michael Blastland of being a tobacco industry hack who is not expressing his sincere scientific criticism, but instead is being orchestrated by the tobacco industry to spout out conspiracy theories. This is not only arguably defamation, but it is essentially McCarthyism. It is an attempt to permanently malign Blastland's reputation and remove him from public discourse. And all of this solely because of the nature, not the quality, of his scientific argument.
Lest readers think that this article from ASH-UK is simply an isolated example, consider that just last week, the European Journal of Public Health published an article in which two other anti-smoking advocates - Pascal Diethelm and Martin McKee - accused all those who do not accept the causal relationship between secondhand smoke and lung cancer/heart disease as being denialists comparable to those who deny the existence of the Holocaust.
Diethelm and McKee argue that the paper by Drs. James Enstrom and Geoffrey Kabat - a meta-analysis which failed to find evidence of a causal relationship between secondhand smoke and lung cancer or heart disease - and its use by various groups is comparable to Holocaust denial.
There are many reputable scientists who have challenged the conclusion that secondhand smoke causes heart disease and lung cancer. While I disagree with their interpretation of the scientific evidence, I would never suggest that their opposing opinion is denialism and that it is comparable to Holocaust denial.
Once again, Diethelm and McKee view the anti-smoking movement as a religion. You have to accept the claims on blind faith and if you don't, you are guilty of heresy. Even worse, you will be publicly attacked and have your character maligned in an attempt to silence you by blacklisting you out of public discourse on the issue.
The rest of the story is that the anti-smoking movement is quickly losing its science base. It is becoming a religious-like, McCarthyist-like movement which attacks and attempts to blacklist anyone who doesn't accept the doctrines of the movement. Its personal attacks are on character, not on science, and are doled out based not on the quality of science in the opposing arguments, but the position that the dissenter has taken.
The most important implication of today's story is that this shift in the movement is now evident not only in the informal statements of the anti-smoking groups, but in the peer-reviewed, published literature. Tobacco control as a religion, rather than as a science-based field of public health practice, is now becoming formally institutionalized.
Dockrell argues that the Pell et al. study, which reported a 17% decline in acute coronary syndrome cases during the first year following the implementation of a smoking ban in Scotland, is conclusive evidence of a causal relationship between the smoking ban and a dramatic and immediate decline in acute cardiac events. He further argues that anyone who disagrees with this conclusion is a denialist, similar to the AIDS denialists, and that such opinion is an orchestrated artifact of tobacco industry lobbying, rather than sincere scientific criticism of the study conclusions.
Specifically, Dockrell argues that: "Organized groups who seek to deny and discredit this work are comparable in nature and intent, but not in origin, to the self-styled AIDS dissidents who continue to deny the causal link between HIV and AIDS and offer a comparable threat to an evidence-based health policy."
Moreover, Dockrell asserts that this dissidence is not pure: it is the result of orchestration by the tobacco industry: "While AIDS dissidence was largely an indigenous phenomenon, tobacco dissidence is the carefully conceived creature of tobacco industry lobbyists."
Readers should keep in mind that I am in fact a major dissenter, as I have criticized the Pell et al. study (critique 1; critique 2; critique 3; critique 4; critique 5; critique 6) and in fact have reported follow-up data which I believe demonstrate that the conclusion from that study was wrong. I have challenged anti-smoking groups to publicize the follow-up data which show that the decline in cardiac events during the first-year after Scotland's smoking ban was followed by an increase in cardiac events during the second year, thus disproving Pell et al.'s conclusion (post 1; post 2).
I take it this means that Dockrell is calling me a denialist and comparing me to AIDS dissidents who still deny that HIV causes AIDS. I also take it to mean that Dockrell is accusing me of being in the pocket of the tobacco companies and acting at their beck and call and presumably -their payments.
In fact, ASH-UK appears to make precisely such an accusation when it states in its press release to accompany the article: "A number of studies have been published recently showing a decline in admissions to hospital for heart attack following the implementation of smokefree laws in various countries. Many of these studies, including one on the impact of the Scottish smoking ban have also been the subject of criticism by so-called "dissidents" who claim that the research is nothing more than 'junk' science. In a recently published review ASH's Director of Policy and Research, Martin Dockrell, looks behind the scenes to see what has prompted this criticism and to what extent it is justified. The analysis finds parallels with those who were in denial about the causes of AIDS long after the scientific debate was over. ... We found an unholy alliance of conspiracy theorists, tobacco industry lobbyists and journalists impatient for a good story."
Dockrell is particularly critical of Michael Blastland, who wrote a commentary published by BBC News on November 14, 2007 which presented data showing that the actual decline in heart attacks in all of Scotland in the year following the smoking ban was similar to that observed in the three years preceding the ban, and that a dramatic decline in heart attacks occurred in 2000, in the absence of a smoking ban. Based on these findings, Blastland questioned the validity of the study's conclusion that the smoking ban was causally related to a 17% decline in acute cardiac events.
Dockrell argues in the article that Blastland is a denialist and conspiracy theorist and concludes that his criticism has been carefully conceived and orchestrated by the tobacco industry: "While AIDS dissidence was largely an indigenous phenomenon, tobacco dissidence is the carefully conceived creature of tobacco industry lobbyists."
The Rest of the Story
This article demonstrates the religious-like and McCarthyist-like nature of the modern-day anti-smoking movement. If you do not subscribe to the accepted dogma of the movement, even when there is legitimate scientific evidence that brings that dogma into question, you are a dissident and a denialist -- on no firmer ground than those who deny that AIDS is caused by the HIV virus. Moreover, you are not expressing a sincere opinion, but are in the pocket of the tobacco industry, part of an orchestrated industry campaign.
The absurdity of the article is evident in its implication that I - a strong anti-smoking advocate - am a denialist who is being orchestrated by the tobacco companies to disseminate conspiracy theories - since I myself have been a vocal critic of the conclusions of these heart attack/smoking ban studies.
Someone who has argued that secondhand smoke kills over 50,000 Americans each year and whose testimony about the tobacco industry's deception of the public contributed towards a $145 billion verdict against the companies is hardly someone who fits the description of being a denialist who is waving around conspiracy theories under orchestration by Big Tobacco.
To be sure, historically the tobacco industry has orchestrated campaigns to undermine the public's appreciation of the recognized hazards of active smoking and secondhand smoke exposure. If you want to read about that history, you need go only so far as to read my testimony in the Engle tobacco case, which initially resulted in a $145 billion verdict against the tobacco companies. It is also true that a number of supposedly independent scientists who have challenged the link between smoking or secondhand smoke and disease have been funded by the industry and have been part of a campaign orchestrated by the industry.
However, the criticism of the research linking smoking bans with a causal effect on acute cardiac events is largely a different story. First, the nature of the evidence is very different. While there is abundant evidence linking smoking and disease and one would have to be a denialist to argue that smoking is not harmful, the research being used to conclude that smoking bans result in huge, immediate declines in heart attacks is very weak. These conclusions are based on time trend analyses, often without a control group, they cannot adequately determine whether observed changes reflect random variation, secular trends, or a real effect of the smoking ban, and thus causal conclusions from these studies are very shaky.
I will not take the time here to explain all the methodologic weaknesses of these studies, but interested readers will find an extensive set of commentaries on my blog which critique this literature.
Perhaps the most important fact to point out here is that studies which have used national, population-based data for all of Scotland have failed to find a 17% decline in heart attacks in Scotland in the year after the smoking ban, and actually found that overall heart attack and angina admissions increased in the second year after the ban, thus negating the earlier decline. Overall, there was little change in heart attack admissions in all of Scotland from before the smoking ban to two years after the ban.
As Christopher Snowdon explained: "Much was made of an apparent reduction in the number of patients being diagnosed with the life-threatening heart condition after the smoking ban came into effect in 2006, including a study published in the New England Journal of Medicine which claimed that the ban had caused emergency ACS [acute coronary syndrome] admissions to fall by 17%. However, official statistics show that the decline in hospitals admissions for acute coronary syndrome has been greatly exaggerated. The real decline in the first year of the smoking ban was just 7.2% - not 17% - and the rate then rose by 7.8% in the second year, cancelling out the earlier drop."
"In the last 12 months before Scotland enacted its smoking ban (April 05 to March 06) there were 16,199 admissions for acute coronary syndrome. In the second year of the smoking ban (April 07 to March 08) there were 16,212 admissions, slightly more than there had been before the legislation was enacted." ...
"Hospital admissions for acute coronary syndrome have been declining in Scotland for many years. The new data show that the well-publicised fall in admissions following Scotland's smoke-free legislation was in line with the existing downward trend and was significantly less steep than has previously been claimed." ... "If the 2006-07 decline had really been the result of the smoke-free legislation, it would be expected for rates to remain low in subsequent years. The fact that Scottish hospitals have seen an unusually sharp rise - despite the smoking ban being rigorously enforced - suggests that whatever lay behind the 2006-07 dip, it was not the smoking ban."
Despite the accusation that Blastland is part of some tobacco-industry orchestrated campaign and that he nothing more than a denialist, Dockrell presents no evidence that either of these is the case. First, he fails to present any evidence showing that Blastland is being paid by Big Tobacco or that he has had any alliance, association, or communication with tobacco companies over his commentaries. Reading other articles written by Blastland, it appears that he is in fact not particularly focused on tobacco, but that he writes in general about many areas in which he believes that statistics have been inaccurately used to draw policy-relevant conclusions.
Second, Dockrell fails to present any evidence to suggest that Blastland's critiques of the smoking ban studies are anything other than legitimate scientific opinions. In fact, I find Blastland's commentary to be quite compelling and from a scientific standpoint, on much more solid ground than the Pell et al. article which was published in the New England Journal of Medicine.
The problem with the Pell et al. study is that its conclusion is based on a comparison of apples to oranges. In order to compare the change in heart attacks in Scotland from 2006-2007 to the trend in heart attacks during the preceding ten-year period, one needs to use the same data source to compare these trends. In the Pell et al. article, the researchers use one source of data to estimate the change in heart attacks from 2006-2007 (observed changes in admissions for nine hospitals representing a portion of the country) and a different source of data to estimate the trend in heart attacks from 1996-2006 (national data from the Scottish National Health Service).
A critical basis for the article's conclusion is that the year-to-year decline in heart attacks in Scotland never exceeded 10%, while the researchers found a 17% decline in heart attacks during the year following the smoking ban. However, the relevant question is not what the national health service data show, but what changes in heart attack admissions would have been found using the same methods employed by the researchers to count heart attack admissions for 2006-2007. What would the annual changes have been using the same 9 hospitals and using the same method of counting heart attack admissions?
In contrast, Blastland presents a consistent data source for hospital admissions throughout all of Scotland for a long period of time: 1998-2007. The graph he presents illustrates that there is no visible change in heart attacks in Scotland in 2006-2007. In fact, the graph shows that the rate of decline in heart attacks in Scotland remained exactly the same as it was prior to the smoking ban.
In addition, the graph shows that there was a substantial decline in heart attacks from 1999-2000 which occurred in the absence of a smoking ban, illustrating that the magnitude of decline in heart attacks in 2006-2007 is actually less than the random variation and secular trends in heart attacks that were observed in Scotland in prior years.
Thus, rather than being denialism, Blastland's criticism of the study is well-founded. Whether he is correct or not, there are absolutely no grounds to dismiss his criticism as being denialism, conspiracy theory, or tobacco industry propaganda being delivered by a paid hack, all of which are implied by Dockrell in his article and press release.
Action on Smoking and Health (UK) evidently views the anti-smoking movement as a religion. Any challenge to the doctrines of the religion amounts to heresy. Scientific discourse is not allowed. You have to accept everything anti-smoking researchers claim with blind faith.
ASH-UK would have the tobacco control movement turn into non-critical automatons, who merely accept, on blind faith, any research which is favorable to the cause. Science would no longer play a role. It would, in fact, become a religion rather than a science-based public health movement.
Moreover, Dockrell's article illustrates the McCarthyist nature of the modern day anti-smoking movement. If you challenge the doctrines of the movement, not only are you viewed as a denialist, but you are automatically attacked as being a Big Tobacco hack. In other words, without any evidence, you are publicly maligned in an attempt to permanently discredit you and blacklist you from any further participation in public discourse.
Dockrell has accused Michael Blastland of being a tobacco industry hack who is not expressing his sincere scientific criticism, but instead is being orchestrated by the tobacco industry to spout out conspiracy theories. This is not only arguably defamation, but it is essentially McCarthyism. It is an attempt to permanently malign Blastland's reputation and remove him from public discourse. And all of this solely because of the nature, not the quality, of his scientific argument.
Lest readers think that this article from ASH-UK is simply an isolated example, consider that just last week, the European Journal of Public Health published an article in which two other anti-smoking advocates - Pascal Diethelm and Martin McKee - accused all those who do not accept the causal relationship between secondhand smoke and lung cancer/heart disease as being denialists comparable to those who deny the existence of the Holocaust.
Diethelm and McKee argue that the paper by Drs. James Enstrom and Geoffrey Kabat - a meta-analysis which failed to find evidence of a causal relationship between secondhand smoke and lung cancer or heart disease - and its use by various groups is comparable to Holocaust denial.
There are many reputable scientists who have challenged the conclusion that secondhand smoke causes heart disease and lung cancer. While I disagree with their interpretation of the scientific evidence, I would never suggest that their opposing opinion is denialism and that it is comparable to Holocaust denial.
Once again, Diethelm and McKee view the anti-smoking movement as a religion. You have to accept the claims on blind faith and if you don't, you are guilty of heresy. Even worse, you will be publicly attacked and have your character maligned in an attempt to silence you by blacklisting you out of public discourse on the issue.
The rest of the story is that the anti-smoking movement is quickly losing its science base. It is becoming a religious-like, McCarthyist-like movement which attacks and attempts to blacklist anyone who doesn't accept the doctrines of the movement. Its personal attacks are on character, not on science, and are doled out based not on the quality of science in the opposing arguments, but the position that the dissenter has taken.
The most important implication of today's story is that this shift in the movement is now evident not only in the informal statements of the anti-smoking groups, but in the peer-reviewed, published literature. Tobacco control as a religion, rather than as a science-based field of public health practice, is now becoming formally institutionalized.
Tuesday, February 10, 2009
Article Provides Convincing Explanation of Why Scotland Heart Attack - Smoking Ban Study is Invalid
An article by Robert Wagner published over at Christopher Snowdon's Velvet Glove Iron Fist provides a novel and very convincing explanation for why the results from the Pell et al. study published in the New England Journal of Medicine are so different from population-based results for all of Scotland and why the study conclusions are invalid.
Background
Pell et al. compared the number of admissions for acute coronary syndrome in nine hospitals in Scotland (representing 63% of admissions for acute coronary syndrome in the country) during the 10-month period prior to the smoking ban and the corresponding 10-month period the following year. The number of admissions declined from 3235 to 2684, a drop of 17%.
This 17% drop was compared to the trend in overall hospital admissions in all of Scotland for acute coronary syndrome during the preceding 10 years. According to the study, "the trend during the 10 years before legislation was a 3% mean annual reduction, with a maximum reduction of 9% in 2000."
Because the observed 17% reduction in admissions for acute coronary syndrome was much higher than the annual reduction during the 10 previous years and exceeded the highest annual decline between any two years, the study concluded that the observed reduction is attributable to the smoking ban.
Importantly, acute coronary syndrome was defined differently in the two time periods that were compared. In Pell et al.'s study of nine hospitals, acute coronary syndrome was defined as any detectable levels of cardiac troponin in the blood. In the population-based data for all of Scotland, acute coronary syndrome was defined by a physician's diagnosis based on the conclusion that the patient suffered either a heart attack or unstable angina. While troponin levels may have been used in the diagnosis, the troponin levels were not definitive in making the diagnosis.
The Rest of the Story
The key point that Wagner makes is that cardiac troponin is not 100% specific for acute coronary syndrome. There are a number of conditions not related to acute coronary syndrome that can cause low levels of troponin in the blood. But high levels are specific to heart damage. Thus, clinicians usually set a threshold level - a level high enough to rule out non-cardiac causes of troponin in the blood.
As Wagner explains: "The troponin test came into common usage in 2000, replacing earlier tests such as creatinine (CK) which were less specific to the heart muscle. A major complaint about troponin is that it delivers too many false positives at low levels. Many conditions cause small concentrations of troponin in the blood; only heart muscle damage causes large concentrations (with a few rare exceptions). The threshold level for a positive reading must be set high enough to eliminate the false positives. Setting the threshold at zero, as Pell did, is scientific nonsense, because it opens the door to MANY false positives."
"The Joint European Society of Cardiology/ACC Committee for the Redefinition of Myocardial Infarction has recommended that an increased concentration of cTn be defined as a measurement exceeding the 99th percentile of cTn concentrations observed in a healthy reference group."
So basing a diagnosis of acute coronary syndrome on ANY detectable level of cardiac troponin - as Pell et al. did - is going to include not only patients with acute coronary syndrome but also a substantial number of false positives.
But here is the clincher: as the cardiac troponin test is relatively new, it has undergone changes over time. New generations of the test have increased specificity for heart damage. Thus, the proportion of false positive tests is decreasing over time.
What does this mean for the Pell et al. study? What it means is that it is quite possible that a major reason for the 17% decline in admitted patients with suspected heart disease who have detectable troponin levels is that the troponin test became more specific and decreased the number of false positives.
In other words, patients who previously might have had a detectable troponin level because of non-cardiac causes would now (in the next generation of test) have a non-detectable level because of improved test specificity.
Wagner does not posit that the increased specificity of the troponin assay is the sole reason for the 17% decline in acute coronary syndrome cases observed in the Pell et al. study. He argues that the increased specificity of the test explains a portion of the decline. In particular, he argues that the changes in the test explain that portion of the 17% decline that exceeds the observed population-based decline in acute coronary syndrome cases, which was about 7%. Thus, there was an "appearance" of an additional 10% decline in acute coronary syndrome cases due to a decline in false positives.
Now, one might ask whether it is possible that the decline in cases of detectable cardiac troponin was so high that it could not be explained by the combination of declining secular trends in heart attacks and declining false positive tests, and thus implicating a role for the smoking ban. The answer is that the only way to determine this would be to compare the decline in cases of detectable cardiac troponin observed in Scotland to that in some comparison country or location without a smoking ban. However, Pell et al. failed to conduct such a comparison. Thus, their study cannot assess whether to smoking ban played any role at all in the observed 17% decline in cases of detectable cardiac troponin in the nine hospitals they studied.
The comparison of the decline in detectable cardiac troponin levels in the nine Scottish hospitals to declines over time in acute coronary syndrome as diagnosed clinically (not based solely on cardiac troponin and using a reasonable minimum cutoff value when troponin is used) during previous time periods is truly comparing apples to oranges, as I argued previously. Wagner's commentary helps to explain exactly why this is.
I should emphasize that the diagnosis of acute coronary syndrome is based on the totality of clinical information available about a patient, including the history, physical exam, electrocardiogram, echocardiogram or other diagnostic tests, and a variety of laboratory tests which may include cardiac troponin. But in Pell's study, what was being measured was not truly the diagnosis of acute coronary syndrome, but rather - the presence of detectable levels of troponin.
Given the decreases in false positive rates over time using the troponin test, it is unclear why Pell et al. would have chosen to include these false positives in their definition of acute coronary syndrome, rather than set a reasonable cut-off level that would have excluded the false positives.
At any rate, what Pell et al. did was not appropriate to make a determination of whether the observed changes were attributable to the smoking ban and for that reason, the conclusions of the study are not valid.
Population-based data on acute coronary events in Scotland have confirmed that there were no significant changes in the rate of decline from before to after the smoking ban. Thus, non-biased analytic techniques have failed to support the hypothesis that the smoking ban in Scotland has resulted in an immediate and dramatic decline in heart attacks.
Background
Pell et al. compared the number of admissions for acute coronary syndrome in nine hospitals in Scotland (representing 63% of admissions for acute coronary syndrome in the country) during the 10-month period prior to the smoking ban and the corresponding 10-month period the following year. The number of admissions declined from 3235 to 2684, a drop of 17%.
This 17% drop was compared to the trend in overall hospital admissions in all of Scotland for acute coronary syndrome during the preceding 10 years. According to the study, "the trend during the 10 years before legislation was a 3% mean annual reduction, with a maximum reduction of 9% in 2000."
Because the observed 17% reduction in admissions for acute coronary syndrome was much higher than the annual reduction during the 10 previous years and exceeded the highest annual decline between any two years, the study concluded that the observed reduction is attributable to the smoking ban.
Importantly, acute coronary syndrome was defined differently in the two time periods that were compared. In Pell et al.'s study of nine hospitals, acute coronary syndrome was defined as any detectable levels of cardiac troponin in the blood. In the population-based data for all of Scotland, acute coronary syndrome was defined by a physician's diagnosis based on the conclusion that the patient suffered either a heart attack or unstable angina. While troponin levels may have been used in the diagnosis, the troponin levels were not definitive in making the diagnosis.
The Rest of the Story
The key point that Wagner makes is that cardiac troponin is not 100% specific for acute coronary syndrome. There are a number of conditions not related to acute coronary syndrome that can cause low levels of troponin in the blood. But high levels are specific to heart damage. Thus, clinicians usually set a threshold level - a level high enough to rule out non-cardiac causes of troponin in the blood.
As Wagner explains: "The troponin test came into common usage in 2000, replacing earlier tests such as creatinine (CK) which were less specific to the heart muscle. A major complaint about troponin is that it delivers too many false positives at low levels. Many conditions cause small concentrations of troponin in the blood; only heart muscle damage causes large concentrations (with a few rare exceptions). The threshold level for a positive reading must be set high enough to eliminate the false positives. Setting the threshold at zero, as Pell did, is scientific nonsense, because it opens the door to MANY false positives."
"The Joint European Society of Cardiology/ACC Committee for the Redefinition of Myocardial Infarction has recommended that an increased concentration of cTn be defined as a measurement exceeding the 99th percentile of cTn concentrations observed in a healthy reference group."
So basing a diagnosis of acute coronary syndrome on ANY detectable level of cardiac troponin - as Pell et al. did - is going to include not only patients with acute coronary syndrome but also a substantial number of false positives.
But here is the clincher: as the cardiac troponin test is relatively new, it has undergone changes over time. New generations of the test have increased specificity for heart damage. Thus, the proportion of false positive tests is decreasing over time.
What does this mean for the Pell et al. study? What it means is that it is quite possible that a major reason for the 17% decline in admitted patients with suspected heart disease who have detectable troponin levels is that the troponin test became more specific and decreased the number of false positives.
In other words, patients who previously might have had a detectable troponin level because of non-cardiac causes would now (in the next generation of test) have a non-detectable level because of improved test specificity.
Wagner does not posit that the increased specificity of the troponin assay is the sole reason for the 17% decline in acute coronary syndrome cases observed in the Pell et al. study. He argues that the increased specificity of the test explains a portion of the decline. In particular, he argues that the changes in the test explain that portion of the 17% decline that exceeds the observed population-based decline in acute coronary syndrome cases, which was about 7%. Thus, there was an "appearance" of an additional 10% decline in acute coronary syndrome cases due to a decline in false positives.
Now, one might ask whether it is possible that the decline in cases of detectable cardiac troponin was so high that it could not be explained by the combination of declining secular trends in heart attacks and declining false positive tests, and thus implicating a role for the smoking ban. The answer is that the only way to determine this would be to compare the decline in cases of detectable cardiac troponin observed in Scotland to that in some comparison country or location without a smoking ban. However, Pell et al. failed to conduct such a comparison. Thus, their study cannot assess whether to smoking ban played any role at all in the observed 17% decline in cases of detectable cardiac troponin in the nine hospitals they studied.
The comparison of the decline in detectable cardiac troponin levels in the nine Scottish hospitals to declines over time in acute coronary syndrome as diagnosed clinically (not based solely on cardiac troponin and using a reasonable minimum cutoff value when troponin is used) during previous time periods is truly comparing apples to oranges, as I argued previously. Wagner's commentary helps to explain exactly why this is.
I should emphasize that the diagnosis of acute coronary syndrome is based on the totality of clinical information available about a patient, including the history, physical exam, electrocardiogram, echocardiogram or other diagnostic tests, and a variety of laboratory tests which may include cardiac troponin. But in Pell's study, what was being measured was not truly the diagnosis of acute coronary syndrome, but rather - the presence of detectable levels of troponin.
Given the decreases in false positive rates over time using the troponin test, it is unclear why Pell et al. would have chosen to include these false positives in their definition of acute coronary syndrome, rather than set a reasonable cut-off level that would have excluded the false positives.
At any rate, what Pell et al. did was not appropriate to make a determination of whether the observed changes were attributable to the smoking ban and for that reason, the conclusions of the study are not valid.
Population-based data on acute coronary events in Scotland have confirmed that there were no significant changes in the rate of decline from before to after the smoking ban. Thus, non-biased analytic techniques have failed to support the hypothesis that the smoking ban in Scotland has resulted in an immediate and dramatic decline in heart attacks.
Wednesday, June 24, 2015
A Must-Read Treatment of the CDC's Campaign of Deception Regarding E-Cigarettes
Dr. Peter Sandman, an expert in risk communication, has written an outstanding, detailed analysis and evaluation of the CDC's public communications regarding electronic cigarettes, focusing on the agency's communications related to its recent MMWR article reporting a dramatic increase in teen e-cigarette use accompanied by a dramatic decline in teen smoking.
His commentary, entitled "A Promising Candidate for Most Dangerously Dishonest Public Health News Release of the Year," provides the most detailed analysis I have seen regarding the CDC's communications surrounding its April 2015 MMWR article. This is an issue about which I have written extensively in the past months. Dr. Sandman supports my arguments with an analysis that is guided by attention to basic risk communication and public health principles.
Dr. Sandman argues that the CDC papered over the most significant finding of the article - that youth smoking dropped dramatically to historically low levels - by considering e-cigarettes to be tobacco products and thereby being able to emphasize, instead, that overall "tobacco" use among youth remained steady.
This would be equivalent to the CDC reporting that heroin use dropped from 10% to 1%, while methadone use increased from 1% to 10%, and putting out headlines noting that there has been no change in opiate use in the population. Or to make it more extreme, suppose that every heroin user switched to methadone and the CDC headline was that opiate use has remained unchanged over time.
Dr. Sandman gives many more relevant examples of the deception in CDC's communications. He also speculates on the reasons for this deception. One hypothesis: "What might lead 12 public health experts to coauthor a report that papers over the comparative risk of vaping versus smoking? I don’t know. Something deeply ideological, I think. Something puritan and fundamentalist. All tobacco use is (equally) evil because it all enriches the tobacco industry? All tobacco use is (equally) disgusting because it all enables users to get illicit pleasure?"
Another important point that Dr. Sandman makes relates to the CDC's absolute refusal to address the relative risks of vaping compared to smoking. He writes: "Frieden’s clarification also tells us why he wanted to talk about the uptick [in overall tobacco use] in the first place. He saw it as a rationale to argue that vaping wasn’t replacing smoking but rather supplementing it. To make this case he ignored not just the small size of the uptick in the number of kids using any tobacco product, but also the absence of any uptick at all in the number of kids using more than one tobacco product, the decline in the number of kids smoking cigarettes, and the decline in the number of kids smoking anything. The real issue here isn’t Frieden’s decision to lean on a statistically insignificant increase in kids’ overall tobacco use to argue against the replacement hypothesis. The real issue is adding apples and oranges. Combining e-cig use, real cig use, and the use of seven other tobacco products into one overall number (the percentage of kids using any tobacco product) means treating the distinction between vaping and smoking as if it were unrelated to health. This is especially deceptive in the absence of any discussion of the decline in total teen smoking between 2011 and 2014."
Dr. Sandman concludes that: "The MMWR report, the CDC news release accompanying the report, and the CDC press briefing about the report are all seriously misleading about the findings of the annual National Youth Tobacco Surveys. The press briefing is the most explicitly misleading of the three, but the news release almost certainly had the most influence on coverage and thus on what the public learned. All three go out of their way to distort the study results and the underlying facts on four key points:
Finally, Dr. Sandman notes that the CDC's communication campaign is not just deceptive, but potentially damaging as well: "The other difference is that the CDC isn’t just exaggerating the risk of e-cigs. It is misrepresenting the comparative risk of e-cigs and real cigs. And it is denying the possibility that vaping might help woo some teenagers from smoking or keep them from starting to smoke in the first place. I frankly don’t care much if the public ends up believing that electronic cigarettes are more dangerous than they really are. But I care enormously if the public – and especially the teenage public – ends up believing that vaping is just as dangerous as smoking so they might as well smoke. Several surveys have shown that while most Americans and most American teenagers still believe that vaping is safer than smoking, the number who believe that vaping and smoking are equally dangerous has climbed substantially. Making that number continue to climb is a key goal of the public health “education” campaign against electronic cigarettes, one small recent piece of which I have discussed in this column."
The Rest of the Story
I urge all of my readers to read Dr. Sandman's excellent critique.
To me, as a former CDC employee (I worked in the Office on Smoking and Health, which is largely responsible for most of these reports and communications), the saddest part of this story is the seeming loss of perspective that has taken place at the agency. In the face of the most dramatic decline in youth smoking in history, the CDC is essentially arguing that there is no cause for celebration because lots of kids are now experimenting with e-cigarettes, which are just as bad as tobacco cigarettes. The CDC has redefined the problem from morbidity and mortality to nicotine use. It doesn't matter how many people die, as long as we minimize the use of nicotine in the population. By the CDC's logic, if every smoker in the nation switched completely to vaping, it would have no public health benefit because the overall use of "tobacco" would remain unchanged.
His commentary, entitled "A Promising Candidate for Most Dangerously Dishonest Public Health News Release of the Year," provides the most detailed analysis I have seen regarding the CDC's communications surrounding its April 2015 MMWR article. This is an issue about which I have written extensively in the past months. Dr. Sandman supports my arguments with an analysis that is guided by attention to basic risk communication and public health principles.
Dr. Sandman argues that the CDC papered over the most significant finding of the article - that youth smoking dropped dramatically to historically low levels - by considering e-cigarettes to be tobacco products and thereby being able to emphasize, instead, that overall "tobacco" use among youth remained steady.
This would be equivalent to the CDC reporting that heroin use dropped from 10% to 1%, while methadone use increased from 1% to 10%, and putting out headlines noting that there has been no change in opiate use in the population. Or to make it more extreme, suppose that every heroin user switched to methadone and the CDC headline was that opiate use has remained unchanged over time.
Dr. Sandman gives many more relevant examples of the deception in CDC's communications. He also speculates on the reasons for this deception. One hypothesis: "What might lead 12 public health experts to coauthor a report that papers over the comparative risk of vaping versus smoking? I don’t know. Something deeply ideological, I think. Something puritan and fundamentalist. All tobacco use is (equally) evil because it all enriches the tobacco industry? All tobacco use is (equally) disgusting because it all enables users to get illicit pleasure?"
Another important point that Dr. Sandman makes relates to the CDC's absolute refusal to address the relative risks of vaping compared to smoking. He writes: "Frieden’s clarification also tells us why he wanted to talk about the uptick [in overall tobacco use] in the first place. He saw it as a rationale to argue that vaping wasn’t replacing smoking but rather supplementing it. To make this case he ignored not just the small size of the uptick in the number of kids using any tobacco product, but also the absence of any uptick at all in the number of kids using more than one tobacco product, the decline in the number of kids smoking cigarettes, and the decline in the number of kids smoking anything. The real issue here isn’t Frieden’s decision to lean on a statistically insignificant increase in kids’ overall tobacco use to argue against the replacement hypothesis. The real issue is adding apples and oranges. Combining e-cig use, real cig use, and the use of seven other tobacco products into one overall number (the percentage of kids using any tobacco product) means treating the distinction between vaping and smoking as if it were unrelated to health. This is especially deceptive in the absence of any discussion of the decline in total teen smoking between 2011 and 2014."
Dr. Sandman concludes that: "The MMWR report, the CDC news release accompanying the report, and the CDC press briefing about the report are all seriously misleading about the findings of the annual National Youth Tobacco Surveys. The press briefing is the most explicitly misleading of the three, but the news release almost certainly had the most influence on coverage and thus on what the public learned. All three go out of their way to distort the study results and the underlying facts on four key points:
- They highlight the bad news (potentially, maybe, somewhat bad news) that teenage e-cigarette use has soared.
- They obscure the good news (definitely, wondrously good news) that teenage real cigarette use and overall smoking are continuing to decline, despite an increase in the use of hookahs.
- They assert that e-cigarettes are dangerous, imply that e-cigarettes are as dangerous as real cigarettes, and hide that virtually all experts agree e-cigarettes are significantly safer than real cigarettes.
- They ignore or deny the suggestive evidence (suggestive but far from conclusive) that teenage vaping might be replacing smoking, not leading to it.
Finally, Dr. Sandman notes that the CDC's communication campaign is not just deceptive, but potentially damaging as well: "The other difference is that the CDC isn’t just exaggerating the risk of e-cigs. It is misrepresenting the comparative risk of e-cigs and real cigs. And it is denying the possibility that vaping might help woo some teenagers from smoking or keep them from starting to smoke in the first place. I frankly don’t care much if the public ends up believing that electronic cigarettes are more dangerous than they really are. But I care enormously if the public – and especially the teenage public – ends up believing that vaping is just as dangerous as smoking so they might as well smoke. Several surveys have shown that while most Americans and most American teenagers still believe that vaping is safer than smoking, the number who believe that vaping and smoking are equally dangerous has climbed substantially. Making that number continue to climb is a key goal of the public health “education” campaign against electronic cigarettes, one small recent piece of which I have discussed in this column."
The Rest of the Story
I urge all of my readers to read Dr. Sandman's excellent critique.
To me, as a former CDC employee (I worked in the Office on Smoking and Health, which is largely responsible for most of these reports and communications), the saddest part of this story is the seeming loss of perspective that has taken place at the agency. In the face of the most dramatic decline in youth smoking in history, the CDC is essentially arguing that there is no cause for celebration because lots of kids are now experimenting with e-cigarettes, which are just as bad as tobacco cigarettes. The CDC has redefined the problem from morbidity and mortality to nicotine use. It doesn't matter how many people die, as long as we minimize the use of nicotine in the population. By the CDC's logic, if every smoker in the nation switched completely to vaping, it would have no public health benefit because the overall use of "tobacco" would remain unchanged.
Wednesday, March 11, 2009
Researchers to Present Data on Changes in Acute Coronary Events After Scotland's Smoking Ban Tomorrow at World Conference on Tobacco or Health
Tomorrow at the World Conference on Tobacco or Health in Mumbai, researchers are scheduled to present the results of their investigation into the changes in acute coronary events in Scotland associated with the implementation of a national smoking ban.
According to the conference abstract: "Our study examined the impact of Scottish smoke-free legislation on hospital admissions for acute coronary syndrome. We collected data prospectively on all patients admitted to nine hospitals in the ten months prior to the legislation (June 05-March 06) and the same ten months following implementation (June 06-March 07). Acute coronary syndrome was defined as raised troponin following emergency admission for chest pain. ... In the 10 years prior to the study, there was a mean annual reduction of 3% (maximum 9%). ... Following the ban, ... admissions fell by 17% (14% among smokers, 19% among ex-smokers and 21% among never smokers). ... Our results suggest that smoke-free legislation is effective at reducing admissions among both non-smokers (due to reduced ETS exposure) and smokers (by encouraging them to reduce consumption or quit)."
The Rest of the Story
It will be most interesting to see whether or not the researchers present more recent national data from Scotland, which demonstrate that the declines in acute coronary events in Scotland during the first year after the smoking ban were offset by increases in those events during the second year. Thus, there was essentially no change in heart attack and angina admissions during the first two years following implementation of the smoking ban.
These data contradict the findings in the abstract and demonstrate that the conclusion in the abstract is incorrect.
The question is: will the researchers share these data, or will they only present the results of their original study, which is now outdated and whose findings have been negated?
The abstract itself is very misleading. It states that acute coronary syndrome was defined as elevated levels of cardiac troponin and that in the 10 years prior to the study there was a mean annual reduction of 3%. This is false. For the 10-year period prior to the study, there was not a mean annual reduction of 3% in acute coronary syndrome as defined by elevated levels of cardiac troponin.
In truth, for the 10-year period prior to the study, acute coronary syndrome was defined based on hospital discharge diagnosis as reported to the national health service. So the authors are comparing apples and oranges. They compare baseline annual decline in acute coronary syndrome diagnosed one way with intervention-period annual decline in the syndrome as diagnosed a completely different way.
Not only is this method invalid, but the abstract is misleading and gives a false impression of what the data actually show.
Should I hear from anyone who attends this session, I will report back on what data the researchers present (or do not present) at the conference.
According to the conference abstract: "Our study examined the impact of Scottish smoke-free legislation on hospital admissions for acute coronary syndrome. We collected data prospectively on all patients admitted to nine hospitals in the ten months prior to the legislation (June 05-March 06) and the same ten months following implementation (June 06-March 07). Acute coronary syndrome was defined as raised troponin following emergency admission for chest pain. ... In the 10 years prior to the study, there was a mean annual reduction of 3% (maximum 9%). ... Following the ban, ... admissions fell by 17% (14% among smokers, 19% among ex-smokers and 21% among never smokers). ... Our results suggest that smoke-free legislation is effective at reducing admissions among both non-smokers (due to reduced ETS exposure) and smokers (by encouraging them to reduce consumption or quit)."
The Rest of the Story
It will be most interesting to see whether or not the researchers present more recent national data from Scotland, which demonstrate that the declines in acute coronary events in Scotland during the first year after the smoking ban were offset by increases in those events during the second year. Thus, there was essentially no change in heart attack and angina admissions during the first two years following implementation of the smoking ban.
These data contradict the findings in the abstract and demonstrate that the conclusion in the abstract is incorrect.
The question is: will the researchers share these data, or will they only present the results of their original study, which is now outdated and whose findings have been negated?
The abstract itself is very misleading. It states that acute coronary syndrome was defined as elevated levels of cardiac troponin and that in the 10 years prior to the study there was a mean annual reduction of 3%. This is false. For the 10-year period prior to the study, there was not a mean annual reduction of 3% in acute coronary syndrome as defined by elevated levels of cardiac troponin.
In truth, for the 10-year period prior to the study, acute coronary syndrome was defined based on hospital discharge diagnosis as reported to the national health service. So the authors are comparing apples and oranges. They compare baseline annual decline in acute coronary syndrome diagnosed one way with intervention-period annual decline in the syndrome as diagnosed a completely different way.
Not only is this method invalid, but the abstract is misleading and gives a false impression of what the data actually show.
Should I hear from anyone who attends this session, I will report back on what data the researchers present (or do not present) at the conference.
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