Drastic Declines in Heart Attack Admissions in Nebraska and South Carolina in 2004: Cut in Anti-Smoking Programs May be the Reason

According to data from the Healthcare Cost and Utilization Project (HCUP) database, there was a dramatic decline in heart attack hospital admissions in Nebraska in 2004 and a sharp decline in heart attack admissions in South Carolina during the same year. These declines in heart attacks coincide precisely with sharp cuts in funding for anti-smoking programs in each of these states.

In Nebraska, heart attack admissions fell by 28.5% from 2003 to 2004. This is in marked contrast to the existing trend in heart attacks in the state. Heart attack admissions were increasing by an average of 2.3% per year during the period 2001-2003 in Nebraska.

In South Carolina, heart attack admissions fell by 12.5% from 2003 to 2004. This is also in marked contrast to the existing trend in heart attacks in that state. Heart attack admissions were increasing by an average of 3.0% per year during the period 2001-2003 in South Carolina.

These declines in heart attacks are much greater than what would have been expected based on trends in other states. In all other states for which data are available, heart attack admissions fell by 5.1% from 2003 to 2004.

The dramatic decline in heart attack admissions in Nebraska coincides with a dramatic cut in funding for the state's tobacco control programs. According to the state: "The Nebraska legislature did away with the funding for this [state tobacco control] program in the spring of 2003. Tobacco Free Nebraska's $21 million ($7 million in each of three years) was cut. Third year funding for Tobacco Free Nebraska was eliminated and the TFN staff resources must rely on state general funds and CDC funds to sustain a skeletal program. Local coalition funding was virtually eliminated as well. ... Tobacco Free Nebraska has launched a $700,000 media campaign to air radio and television commercials with anti-smoking themes. ... This effort has been eliminated by the historic legislative cut of the spring 2003."

It appears, then, that the historic legislative cut in anti-smoking programs in 2003 resulted in the greatest decline in heart attack admissions observed in Nebraska and in the successful reversal of the increasing trend in heart attacks in the state.

The huge decline in heart attack admissions in South Carolina, which reversed that states trend of increasing heart attack admissions during the previous two years, coincided with the complete elimination of what had been a successful anti-smoking program conducted during the previous four years.

These declines in heart attacks, which buck the national trend, occurred in states which have enacted no statewide smoking bans, few if any local smoking bans, and which both received grades of F in 2004 from the American Lung Association for the category of Smokefree Air in its State of Tobacco Control 2004 Report Card.

The Rest of the Story

Of course the observed declines in heart attacks in Nebraska and South Carolina in 2004 were not due to the cuts in anti-smoking programs. But this demonstrates the danger of using data from one year after an event to draw conclusions regarding the effect of that event on the phenomenon of interest, especially when the sample is small and there is great baseline variation.

This is why the claims being made from Helena, Pueblo, and Saskatoon are so suspect. In these studies, data from one year (6-18 months) after a smoking ban was implemented are being used to suggest that the smoking ban resulted in that single year's observed decline in heart attack admissions. Essentially, you have a single data point that is being used not only to assume that a definite trend is present but to ascertain the cause of the change in the statistic for that single year.

The reasoning used here is exactly the same as that used in the Helena, Pueblo, and Saskatoon studies. Baseline trends in heart attack admissions for a period of roughly four years prior to the event of interest were studied to establish the baseline trend in heart attack admissions. Then the heart attack data for the first year following implementation of the event of interest were used to assess the effect of the event on heart attack admissions. A dramatic decline in heart attacks was observed that coincided perfectly with the event in question. No similar decline (to the same extent) was observed in a number of control states that did not have the event of interest. Using the same reasoning as in Helena, Pueblo, or Saskatoon, one would conclude that the cut in anti-smoking programs resulted in the dramatic 28.5% decline in heart attack admissions in Nebraska in 2004 and in the large 12.5% decline in heart attack admissions in South Carolina in 2004.

This is shoddy science. It's shoddy because there is simply too much underlying variability in the data to establish a definite trend from one year's data point and to eliminate the possibility that the single year change that is being observed is simply due to random variation, rather than to an effect of the smoking ban.

And here, the sample sizes are huge compared to any of the studies that are being relied upon to claim that smoking bans dramatically and immediately reduce heart attack rates. In Nebraska, there were about 1800 heart attack admissions per year, compared to only about 80 in Helena. The Helena conclusion was based on a reduction of about 16 heart attacks, while the Nebraska "conclusion" is based on a reduction of about 540.

In fact, an examination of the HCUP data reveal that the variation in heart attacks is rather strongly related to the sample size. In states with very large populations, there is little variability. For example, in the two largest states in the database (Florida and California), there was no year-to-year variation of greater than 5.5%. But in the smallest state (Hawaii), there was as much as a 15% year-to-year variation in heart attack admissions.

With small populations, it is going to take more than just five years of data to adequately establish baseline trends and to estimate the random variability in heart attack admissions. And it is going to take more than one year to establish that a definite change in the trend has occurred, rather than simply random variation.

Massachusetts is a great example of this. There was a 12.0% decline in heart attacks in Massachusetts in 2004. This is in sharp contrast to the average 9.2% increase in heart attacks in Massachusetts during the period 2001-2003. Does this mean that something which occurred in late 2003 or early 2004 caused the sharp decline?

We can't really tell yet. First of all, we would need to know the underlying variation in the data. Do we observe changes from year-to-year in Massachusetts of this magnitude?

Well, from 2001 to 2002, heart attack admissions in the state increased by 18.3%, but admissions were essentially stable from 2002 to 2003. Is this just random variation, or is there a real trend? You need to go back further than 2001 and farther ahead than 2004 to find out. After all, there were more heart attacks in Massachusetts in 2004 than in 2000. That certainly doesn't sound like a trend of declining heart attacks. The 2005 data point may help to clarify this. If heart attacks continue to fall, then it appears there may be a real trend. But if they are up a little, it will make it appear that there is just a fair amount of variability occurring.

The bottom line is that even in a large population with many heart attacks occurring, we cannot draw causal conclusions regarding the effect of smoking bans based on these data. It is hard to imagine drawing sweeping causal conclusions from similar data in a population that is exceedingly smaller. It's hard to believe that a change in heart attack admissions from 40 to 24 is being used as the basis of a national campaign to convince the public that acute secondhand smoke exposure causes heart attacks.

The rest of the story is that shoddy science is being used to promote smoking bans and the science is shoddy because one cannot validly conclude that the observed year-to-year change in one data point in the rather small populations of Helena, Pueblo, and Saskatoon were due to the smoking ban, rather than to baseline variation, secular changes, or some other factors.

New Data Show Decline in M.I. Admissions in Smoke-Free States is Lagging Behind Decline for Nation; Casts Doubt on Helena/Pueblo/Saskatoon Claims

Data recently released by HCUPnet, a service of the Agency for Healthcare Research and Quality (AHRQ), show that there was a substantial decline (8.2%) in heart attack hospital admissions in the United States between 2003 and 2004. This followed a smaller decline of 2.8% between 2002 and 2003. Overall, the decline in heart attack admissions in the U.S. between 2002 and 2004 was 11%.

These sharp declines in heart attack admissions suggest that the conclusion of recent studies that smoking bans caused declines in heart attacks in Helena, Pueblo, and Saskatoon are highly suspect, as these studies fail to control for the fact that during the same period of time as these smoking bans went into effect, a secular change in heart attack admissions was occurring.

An analysis of heart attack trends in states that implemented smoking bans in recent years (but prior to 2004, which is the most recent year for which heart attack data are available) reveals that there is no evidence that smoking bans led to a decline in heart attack admissions in these states.

In New York, a smoking ban in all bars and restaurants was implemented in July, 2003. A similar ban in New York City had been implemented in March of that year. If smoking bans caused a drastic and immediate decline in heart attacks (40% in 6 months was claimed by the Helena study), then one would certainly expect to have seen a substantial decline in heart attack admissions in New York State in 2003 and 2004.

However, heart attack admissions in New York State dropped by only 0.5% in 2003, and by 3.2% in 2004, compared with the national declines of 2.8% and 8.2%, respectively. Overall, the decline in heart attack admissions in New York State from 2002 to 2004 was only 2.7%, compared to a 10.7% drop in the nation as a whole.

In Florida, a smoking ban in all restaurants was implemented in July, 2003. If smoking bans caused a drastic and immediate decline in heart attacks on the order of 40% (as claimed in Helena) or 27% (as claimed in Pueblo), then one would certainly expect to have seen a substantial decline in heart attack admissions in Florida in 2003 and 2004.

However, heart attack admissions in Florida dropped by only 0.7% in 2003, and by 2.0% in 2004, compared with the national declines of 2.8% and 8.2%, respectively. Overall, the decline in heart attack admissions in Florida from 2002 to 2004 was only 2.7%, compared to a 10.7% drop in the nation as a whole.

During the period 2003-2004, the precise period when smoking bans were implemented in New York and Florida, these states lagged substantially behind the rest of the nation in their observed rates of decline in heart attack admissions. Instead of seeing a 40%, or even 27% decline in heart attack admissions in these states, there was less than a 3% decline over two years, and this was in the face of a nearly 11% decline in the nation as a whole during the same period.

The Rest of the Story

Obviously, I am not concluding from this analysis that smoking bans cause heart attacks. But it is perhaps worth noting that the same methodology used by the Helena, Pueblo, and Saskatoon studies would lead to such a preposterous conclusion. This is the problem with attributing any observed changes in a health outcome to one particular change (i.e., a smoking ban) and ignoring all other possible changes that occurred, including random changes in the health outcome itself.

The problem is particularly troublesome in very small samples, such as those in Helena, Pueblo, and Saskatoon.

The bottom line is that there simply is not evidence to support the conclusions being disseminated by a large number of anti-smoking groups that smoking bans lead to dramatic decreases in heart attacks. This is an unsubstantiated health claim if I've ever heard one.

But the lack of evidence to substantiate the claim, as well as the lack of plausibility of the claim, do not appear to be stopping anti-smoking groups from making the claim, and from using this as propaganda in their efforts to promote smoking bans.

If you are going to be a credible scientist, you have to be willing to look at the data. I have done that, and I conclude that there is not evidence to support a contention that smoking bans will dramatically reduce heart attacks. If anything, the evidence suggests that this is not the case. Unfortunately, it doesn't appear to me that many anti-smoking researchers and groups are willing to even look at this evidence. Instead, they simply attack those calling this to their attention as being tobacco industry sympathists.

That is one thing I am not.

However, I am starting to sympathize with those who are getting sick and tired of seeing anti-smoking groups continue to spout propaganda that is unsupported by the science. Yes, I'm starting to feel your pain.

New Study of National Heart Attack Admissions and Mortality Finds No Evidence of a Short-Term Effect of Smoking Bans

Most Definitive Study to Date Refutes Conclusions of Many Earlier Studies and Demonstrates Why These Studies Obtained Positive Findings

A new study by researchers from the RAND Corporation, Center for Studying Health System Change, University of Wisconsin, and Stanford University is the first to examine the relationship between smoking bans and heart attack admissions and mortality trends in the entire nation, using national data. All previous U.S. studies only examined one particular city. In contrast, this study examined data from the Nationwide Inpatient Survey (NIS), which is nationally representative and includes 20% of all non-federal hospital discharges in the United States. The study appears in the Winter 2011 issue of the Journal of Policy Analysis and Management.

Study citation: Shetty KD, DeLeire T, White C, Bhattacharya J. Changes in U.S. hospitalization and mortality rates following smoking bans. Journal of Policy Analysis and Management 2011; 30(1):6-28.

The key conclusions of the study are as follows:

1. "In contrast with smaller regional studies, we find that smoking bans are not associated with statistically significant short-term declines in mortality or hospital admissions for myocardial infarction or other diseases."

2. "An analysis simulating smaller studies using subsamples reveals that large short-term increases in myocardial infarction incidence following a smoking ban are as common as the large decreases reported in the published literature."

The study uses state and local workplace smoking ordinance data from the American Nonsmokers' Rights Foundation tobacco control database for the years 1989 through 2004 and national data on heart attack admissions and mortality from the National Inpatient Survey (1993-2004), as well as from the Multiple Cause of Death database (1989-2004) and Medicare Provider Analysis and Review files (1997-2004). Using a fixed effects regression model, the authors analyze outcomes (heart attack admissions and mortality) before and after the implementation of all workplace, bar, or restaurant smoking bans in the nation, as identified in the ANR database.

The regression coefficient of interest represents the change in heart attack admissions or mortality associated with the implementation of a smoking ban, while controlling for secular trends in the outcome variable as well as regional differences in outcomes and regional differences in population size, number of physicians, number of hospital beds, household income, and percent of the population in the labor force.

The study also simulates the results from the comparison of all possible combinations of regions in the U.S. by examining subsets of the data, where one region is an intervention unit and the other is a comparison or control unit. The authors are therefore able to simulate what the results would be for each of the 15,824 possible comparisons of intervention and control regions in the country.

The main study result is that the regression coefficients for the smoking ban variable is not statistically significant in either the heart attack admission or heart attack mortality model, indicating that the smoking bans had no effect on either heart attack admissions or heart attack mortality.

The study estimates that workplace smoking laws increased heart attack mortality by a non-significant 1.9%, with a 95% confidence interval of -0.9% to +4.7%. The study estimates that workplace smoking laws reduced heart attack admissions among 18-64 year-old adults by a non-significant 3.6%, with a 95% confidence interval of -9.6% to +2.5%.

The study estimates that workplace smoking laws reduced heart attack hospitalizations by a non-significant 2.0%, with a 95% confidence interval of -7.0% to +3.0%. The study estimates that workplace smoking laws increased heart attack admissions among 18-64 year-old adults by a non-significant 1.8%, with a 95% confidence interval of -4.5% to +8.0%.

There was also no significant effect of any smoking restrictions (including bar and restaurant smoking bans) on either heart attack admissions or mortality.

Most interestingly, the simulation of all possible comparison studies of local regions in the U.S. finds that just as many studies would find an increase in heart attacks associated with smoking bans as would find a decrease in heart attacks (see Figure 2). The mean difference in heart attack admissions among all studies was 0. The exact same result was found for heart attack mortality (see Figure 3).

The paper concludes: "We find no evidence that legislated U.S. smoking bans were associated with shortterm reductions in hospital admissions for acute myocardial infarction or other diseases in the elderly, children, or working-age adults." ...

"We show that there is wide year-to-year variation in myocardial infarction death and admission rates even in large regions such as counties and hospital catchment areas. Comparisons of small samples (which represent subsamples of our data and are similar to the samples used in the previous published literature) might have led to atypical findings. It is also possible that comparisons showing increases in cardiovascular events after a smoking ban were not submitted for publication because the results were considered implausible. Hence, the true distribution from single regions would include both increases and decreases in events and a mean close to zero, while the published record would show only decreases in events. Publication bias could plausibly explain the fact that dramatic short-term public health improvements were seen in prior studies of smoking bans." ...

"We show that positive and negative changes in AMI incidence are equally likely after a smoking ban, which suggests that publication bias, not outcome heterogeneity, explains the skewed results seen in prior reviews. The IOM and other policymakers have relied on the weight of the published literature when making decisions. However, it appears that publication bias did not receive sufficient attention. Our results suggest that only positive studies have been published thus far, and the true short-run effects of governmental workplace smoking bans would be more modest in the U.S. inclusion of such unpublished negative studies might change the conclusions of the IOM and other decision makers on this issue."

The Rest of the Story

Without a doubt, this is the most definitive study yet conducted of the short-term effects of smoking bans on cardiovascular disease.

To give you an idea of the scope of this study compared to previous ones, the Helena study involved a total of 304 heart attack admissions in one community over a period of six months. This study examined a total of 673,631 heart attack admissions and more than 2 million heart attack deaths in 467 counties across all 50 states over an 16-year period.

This study fails to find any significant short-term effect of smoking bans on heart attack admissions or heart attack mortality, although a small effect cannot be ruled out. The study refutes the claims from previous studies that smoking bans result in a short-term reduction in heart attacks in the range of 20-40%, as many anti-smoking groups are asserting. It also refutes the conclusion of the Institute of Medicine that smoking bans result in immediate, substantial declines in heart attack admissions.

The most important finding of this study is that there are just as many smoking ban communities in which heart attack admissions and mortality have increased in comparison with control communities as there are smoking ban communities in which heart attacks have decreased relative to control communities. The mean difference was found to be zero.

Thus, the study not only fails to find a short-term effect of smoking bans on heart attacks, but it also explains the positive findings of previous studies. What appears to be going on is what is referred to as publication bias.

What this means is the following: if one wanted an unbiased estimate of the effect of smoking bans on heart attacks, one would ideally include all communities that have enacted a smoking ban. In reality, what has occurred is that there have been what essentially amount to anecdotal studies conducted in several communities. These few studies have been published in the literature. It is possible that similar studies were conducted that failed to find an effect and that these studies were therefore not published. It is also possible that the finding of positive results in the few communities studied was essentially a result of chance. There may be other reasons why certain communities were selected for study. For example, researchers may subconsciously have a feeling that heart attacks have decreased and may want to conduct research to confirm if this is the case or not.

For whatever reason, it is apparent that the sample of communities in which this issue has been studied represents a biased sample of all possible studies that could have been conducted. When one examines, systematically, data for all regions in which smoking bans have been enacted, one fails to find a significant effect of smoking bans on either heart attack admissions or heart attack mortality.

This doesn't meant that smoking bans will not eventually result in reductions in cardiovascular disease. That will take considerable time. It just means that the conclusions of anti-smoking researchers and groups that heart attacks drop immediately upon passage of smoking bans appear to be wrong.

When I first questioned the validity of the conclusions of the Helena and Pueblo studies, I was attacked by many of my colleagues, called a traitor, and expelled from list-serves because they did not want me to spread my dissenting opinion. Now, it has become quite clear that my skepticism was well-placed to begin with. The most definitive study to date has refuted the findings of these studies.

It is important for me to point out that I never took issue with the data presented in the individual studies. There were demonstrable declines in heart attack admissions in the intervention cities. What I questioned was the conclusion that these declines were attributable to the smoking ban, rather than to random variation in the data and/or secular changes in heart attacks, which we know are declining throughout the country, even in the absence of smoking bans. There have been considerable advances in surgical and pharmaceutical treatments for coronary heart disease and these may well be the major contributing factors to the observed decline in heart attack rates.

This new research demonstrates why tobacco control researchers and groups have to be very careful in drawing causal conclusions, and why it is better to uphold high standards of scientific rigor rather than to jump to premature conclusions that may later be shown to be incorrect. Tobacco control groups, and the movement as a whole, will lose some scientific credibility because of these new findings which do not support their conclusions. But it is too late to retract those conclusions because they have already been widely disseminated through the media.

It is far better to get it correct the first time. But that requires adherence to solid science. You cannot allow advocacy concerns and goals - no matter how noble they may be - to interfere with the process of objective scientific evaluation. That is exactly what has occurred in tobacco control.

The rest of the story is the best available evidence does not support the conclusion that smoking bans have resulted in immediate, substantial declines in heart attack admissions, as anti-smoking groups as well as the Institute of Medicine boasted. The anti-smoking groups and IOM did not adequately take into account the role of publication bias. Neither did they adequately take into account the lack of control groups in most of the studies, as well as the failure of these studies to rigorously control for secular trends in heart attack admissions and to rule out alternative explanations for the study findings.

Of course, my readers will understand that the lack of a short-term effect of smoking bans on heart attacks does not mean that these are not important policies that protect the public's health. It simply means that anti-smoking groups have been wrong in touting this claim and that the scientific rigor in the anti-smoking movement has disintegrated.

Now here is the really interesting question:

Will anti-smoking groups share and/or publicize the results of this new study or will they simply ignore evidence that does not fit their pre-determined conclusions?

Massachusetts Study Shows Lower Smoking Prevalence Associated with Reduced Heart Attack Rates, But Doesn't Show Any Immediate Effect of Smoking Bans

After careful examination of the study released last week by the Massachusetts Department of Public Health, it is clear that the study fails to show any immediate decline in heart attacks following passage of the statewide smoking ban. The study does demonstrate, however, that declining smoking prevalence is closely tied to declines in heart attack rates. Thus, while the study documents that interventions - such as smoking bans - which reduce smoking prevalence will eventually result in declines in heart attacks, it does not provide any evidence that smoking bans will immediately reduce heart attacks. This study refutes, rather than supports the conclusion of studies from Helena, Pueblo, Bowling Green, and several other sites.

The Rest of the Story

The study was designed primarily to examine whether the statewide smoking ban, implemented on July 5, 2004, resulted in an immediate drop in heart attack deaths. In the first year after the smoking ban was implemented, there was no significant decline in heart attack deaths in the state. Moreover, there was no decline in heart attack deaths even among just those residents living in towns that did not previously have smoking bans. Thus, this study refutes the conclusions from Helena, Pueblo, Bowling Green, etc. that smoking bans immediately reduce heart attacks by decreasing secondhand smoke exposure.

The study did find a decline in heart attack rates from the first to second year after the statewide smoke-free law was implemented, but it turns out that the magnitude of this decline was not significantly different in towns with or without smoking bans prior to the state law. Thus, the study provides no evidence that the statewide smoking ban was associated with any significant decline in heart attacks, even up to two years after its implementation.

While not the primary purpose of the study, it did incidentally find that heart attack death rates were significantly lower, over the long-term period of 1999-2006, among residents of towns with smoking bans compared to residents living in towns without such bans. The mean smoking prevalence in these towns was substantially lower in these towns (17.6% vs. 20.1%). These data provide evidence that smoking prevalence is (not unexpectedly) closely related to heart attack death rates. From this, one can conclude that the observed declines in heart attack rates over time is due, in part, to the observed declines in smoking prevalence. It should be emphasized, however, that these are long-term effects that occur over a long period of time, not the six months to one year that were touted in the Helena et al. studies.

The rest of the story, then, is that the Massachusetts study provides no evidence that smoking bans are associated with an immediate decline in heart attacks and that it in fact refutes the conclusions of previous studies that heart attack rates decline within the first six months to one year following implementation of smoking bans. The study does, however, demonstrate that declines in smoking prevalence will, over time, result in declines in heart attack deaths.

The lack of solid scientific data that smoking bans lead to immediate reductions in heart attacks is not stopping anti-smoking advocates from making such a claim. In a press release from the Henry Ford Health System, the lead author of a new study on this very topic stated: "If Michigan were to implement a comprehensive smoking ban tomorrow, we would see a 12 percent drop in heart attack admissions after the first year."

Note that this study is simply a review of the previous flawed literature (Helena et al.). It provides no new evidence. Unfortunately, the statement by this researcher is unsupported by the scientific evidence. But as I have noted recently, anti-smoking advocates are now holding themselves to very low scientific standards. What now passes for science is what in the past we would have called an interesting anecdote.

One final point deserves emphasis. The release of the Massachusetts study represents yet another example of "science by press release." I do not understand why the researchers didn't wait until the study was accepted for publication and then release the results when the article was published, which is the usual practice. Since the study has been submitted for publication, it would have made sense to wait until publication to release the findings. In fact, many journals will not allow researchers to release a study to the public while it is under review.

If the study was not being submitted for publication, it would be a different matter (assuming that the full study was made available for public review). But because the study is under review at a journal, it cannot be released publicly. Thus, there is no opportunity for scrutiny and review of the study conclusions.

It is very interesting to me that it is always these heart attack and smoking ban studies that are released prior to scientific review. It almost makes one think that the researchers are subconsciously aware that the conclusions are shoddy and that they want to get press coverage of their hoped-for conclusions before the results are actually held up to high scientific standards. I have to admit that it's a great strategy, because once the results are disseminated through the media, it is too late to retract or clarify them later.

New Study Concludes that Italian Smoking Ban Reduced Heart Attack Rates Within First Year

An article published online ahead of print in the journal Circulation concludes that the ban on smoking in public places in Italy has resulted in an 8%-11% decline in acute coronary events (i.e., heart attacks) in the first year following implementation of the ban (see: Cesaroni G, Forastiere F, Agabiti N, et al. Effect of the Italian Smoking Ban on Population Rates of Acute Coronary Events. Circulation 2008).

The study compared the annual age-standardized rates of acute coronary events among adults in three different age groups during the five years preceding the smoking ban (2000-2004) to the rates during the first year the ban was in effect (2005). The post-smoking ban acute coronary event rate was 11% lower than the pre-ban rate for adults ages 35-64 and 8% lower for adults ages 65-74. There was no significant difference in the pre- and post-ban rates for adults ages 75-84.

The authors conclude that the observed reduction in the heart attack rate in 2005 among 35-74 year-olds was atributable to the smoking ban. Furthermore, the authors conclude that at least a portion of the effect is due to a reduction in secondhand smoke exposure among nonsmokers.

One study author stated: "Smoking bans in all public and workplaces result in an important reduction of acute coronary events."

These conclusions have been widely reported. For example, this article was headlined: "Public smoking ban decreases acute coronary events in Italy."

Results of this and related studies (with similar methodology) are being used by anti-smoking advocates in testimony before policy makers that smoking bans have an immediate effect on heart attack rates.

The Rest of the Story

There's just one problem with all of this: the conclusions of this study are not supported by the data. The data clearly show that the decline in heart attack rates among adults in these two age groups began prior to the implementation of the smoking ban. Thus, it is evident that the decline is not attributable to the smoking ban.

Take a look at the data for yourself:

A. Age 65-74

From 2003 to 2004 (prior to the smoking ban), the heart attack rate declined from 7.86 to 7.39, a drop of 6.0%.

From 2004 to 2005 (first year of the smoking ban), the heart attack rate declined from 7.39 to 6.95, a drop of 6.0%.

In other words, the decline in the heart attack rate from 2003 to 2004 was exactly the same as the decline from 2004 to 2005.

These data clearly do not support the conclusion that the smoking ban resulted in a sudden drop in the heart attack rate. Instead, these data document that the decline in the heart attack rate in this age group was exactly the same post-ban as it was pre-ban.

In light of these data, I find it impossible and highly invalid to conclude that the smoking ban resulted in the observed decline in heart attacks from 2004 to 2005. A more likely, and certainly plausible, explanation is that there was already a trend of declining heart attack rates and that this trend simply continued from 2004 to 2005.

The precise reasoning being used by this paper could equally be used to argue that the smoking ban had no effect on heart attacks. I'm not making such a claim, but I am suggesting that these data by no means support the conclusion of the article. In fact, they refute such a conclusion.

B. Age 35-64

From 2002 to 2003 (prior to the smoking ban), the heart attack rate declined from 2.13 to 1.95, a drop of 8.5%.

From 2004 to 2005 (the first year of the smoking ban), the heart attack rate declined from 1.92 to 1.80, a drop of 6.3%.

In other words, the observed decline in the heart attack rate one year prior to the smoking ban was actually greater than the decline in the heart attack rate after the smoking ban.

The average decline in the heart attack rate for the two year period preceding the smoking ban (2002 to 2004) was 4.9%.

The decline in the heart attack rate for the first year following the smoking ban was 6.4%.

Thus, one can see that the decline in the heart attack rate in this age group after the smoking ban was comparable to the decline in the heart attack rate in this age group before the smoking ban.

Once again, these data clearly do not support the conclusion that the smoking ban resulted in a sudden drop in the heart attack rate. If anything, these data document that the decline in the heart attack rate in this age group was about the same post-ban as it was pre-ban.

In light of these data, I find it impossible and highly invalid to conclude that the smoking ban resulted in the observed decline in heart attacks from 2004 to 2005. A more likely, and certainly plausible, explanation is that there was already a trend of declining heart attack rates and that this trend simply continued from 2004 to 2005.

The precise reasoning being used by this paper could equally be used to argue that the smoking ban had no effect on heart attacks. Again, I'm not making such a claim, but I am suggesting that these data by no means support the conclusion of the article. In fact, they refute such a conclusion.

What is so alarming about the conclusion of this Italian smoking ban study is not so much that the authors have drawn a conclusion that follows from the data but have failed to consider alternative explanations for the cause of the decline in heart attack rates. What is so alarming is that they have drawn a conclusion that is completely unsupported by the data itself.

In other words, what appears to be operating here is an investigator bias, by which the authors seem to have been determined to find an effect even if one did not exist. It appears that this bias probably skewed their judgment in evaluating these data.

If you want to see what I mean, plot the heart attack rates for yourself on a graph. I used Microsoft Excel to do this and it took just a few minutes.

Then, examine the trend in heart attack rates among the age groups visually. For the 35-64 year-old group, you will readily see that there is literally a straight line from 2002 to 2005. There is an apparent decline in the heart attack rate that has remained relatively stable during the past few years. But that decline started in 2002, not in 2004.

Similarly, if you look at the graph for the 65-74 year-old group, you will see that there is literally a straight line from 2003 to 2005. There is indeed a trend of a declining heart attack rate, but that decline starts in 2003.

The appropriate conclusion from these data is that there is indeed a significant decline in the heart attack rates among 35-74 year-olds, but that this decline preceded the implementation of the smoking ban. The smoking ban certainly does not seem to have done anything to alter the existing observed declines.

This does not prove that the smoking ban had no effect. But what it does is indicate that the conclusion of the study is completely invalid.

There is another serious problem which, independently of the improperly interpreted data, renders the study conclusion invalid. That problem is simple: there is no comparison group. Without a comparison group, it is impossible to know whether the observed changes in heart attack rates in Italy are unique to Italy or whether they mirror similar secular changes occurring elsewhere.

We happen to know, for example, that in the United States, there have been substantial declines in heart attack rates - even in states without smoking bans - during the same time period. There is no way that the study can conclude that the observed decline in Italy is not simply a reflection of the underlying secular trend of declining coronary event rates that is occurring anyway, even in the absence of the smoking ban.

What I find highly intriguing is the apparent bias that is plaguing the interpretation of these smoking ban/heart attack studies, from Helena to Pueblo to Saskatoon to Bowling Green to Ireland to Scotland to Piedmont to Rome.

What I think this shows is that if one wants strongly enough to be able to find an effect of something, that can skew ones interpretation and analysis of the data such that one is able to do so. That is somewhat reasonable, since there is always going to be an inherent bias in any scientific study.

But what is not so reasonable to me is that these inherent biases and the skewed and invalid interpretation of the data are not being picked up by journals. It suggests that perhaps the peer reviewers who are being chosen to review these studies are affected by the same bias. If these papers are not being reviewed by scientists who are neutral, then those reviewers are far less likely to pick up the glaring flaws in these study conclusions. It certainly appears that may have been what happened in the case of Rome.

Large Meta-Analysis Purports to Find Huge Effect of Smokefree Laws on Heart Attacks, But Instead Fails to Demonstrate an Effect

In the largest meta-analysis to date of studies examining the effect of smoking bans on heart attack admissions, a paper published this week in the journal Circulation concludes that smoking bans lead to an immediate 15% decline in heart attack admissions or deaths. The typical follow-up period in the reviewed studies was approximately one year. Thus, the paper is concluding that smoking bans produce a 15% decline in heart attacks in the first year following implementation of these bans. Furthermore, the paper argues that the observed decline is due to a reduction in secondhand smoke exposure. Most of the policies were bans on smoking in restaurants and/or bars.

The basic method of the study was as follows: "We included studies examining the association between smokefree laws and hospitalizations or deaths due to cardiovascular or respiratory disease with sufficient data to calculate the relative risk and confidence interval before and after... ."

The article concludes: "Consistent with 3 prior meta-analyses that concluded that smoke-free laws are associated with significant decreases in AMI and other cardiac hospital admissions, we found that comprehensive smoke-free laws (covering workplaces, restaurants, and bars) were associated with a
15% decrease in AMI hospitalizations."

The Rest of the Story

Unfortunately, this article doesn't do what it purports to do.

What the Study Does: The study examines changes in the rates of heart attack admissions or deaths from before to after the implementation of smoking bans in a large number of localities. It provides convincing data to conclude that in these localities, there was an overall 15% decline in heart attack admissions or deaths during the time period when smoking bans were implemented in these localities. There is no question that the implementation of smoking bans has been associated with a decline in heart attacks, and the best estimate for the magnitude of that decline is about 15%.

What the Study Doesn't Do: The study doesn't examine the observed changes in heart attacks in localities with smoking bans in light of secular changes in heart attack rates that were occurring during the same time period in localities that did not enact smoking bans. In other words, the meta-analysis did not include any comparison group. In fact, the study did not restrict inclusion to articles that used a comparison group. Generally, the estimates in the paper refer to the relative risk for heart attack admissions or deaths after the smoking ban compared to before the ban. All we can conclude from the study is that there was a decline in heart attacks during the study period. However, there is no way to discern whether the observed decline was attributable to the smoking ban. To do that, we would need to compare the rate of decline observed in these localities to the rate of decline in heart attacks during the same time period in localities without smoking bans.

This might not be a problem if heart attack rates had generally been stable during the study period. But due to medical interventions and pharmaceutical advancements, heart attack rates have generally been falling during the study period, even in the absence of smoking bans. To conclude that the observed changes were due to the smoking bans, one must compare the rates of decline in heart attacks in the localities with smoking bans to the rates of decline in localities without smoking bans. The meta-analysis fails to make this comparison. Therefore, while I believe that it demonstrates a clear reduction in heart attacks in localities with smoking bans, its conclusion that these reductions are attributable to the smoking bans is invalid.

We can, however, derive estimates of the overall decline in heart attack admissions in the United States during the approximate study period. The Health Care Utilization Project (HCUP) provides data on heart attack admissions from a large national inpatient sample. Based on these data, the national trend in heart attack admissions during the period 2002 to 2006 shows a decline of 17.2%. From 2003 to 2005 alone, the decline in heart attack admissions nationally was 15.7%.

So if the expected decline in heart attacks during the period 2003-2005 is 15.7% and in localities with smoking bans, the observed decline is 15%, how can one possibly conclude that the smoking bans led to a decline in heart attacks? My point here is simply to demonstrate that declines in heart attack admissions on the order of about 15% would not be unexpected in the U.S. in the absence of smoking bans, based on an examination of overall trends in the country occurring anyway.

One final note. As with the study I have been discussing over the past few days in which I revealed investigator bias, this study too shows evidence of the same type of bias. Specifically, the authors excluded from the analysis a study which found no effect of smoking bans on heart disease deaths in six states.

In that study, the authors examined age-adjusted rates of heart attack mortality during the 3 years before implementation of the smoking ban and during the first year after the smoking ban was implemented in the eight states that implemented smoking bans between 1995 and 2003. These trends were also compared with those in the 44 other states without smoking bans.

The results were that in four of the six states (California, Utah, Delaware, and South Dakota), the smoking bans were not associated with any significant short-term decline in heart attack mortality. In one of these states - South Dakota - there was an 8.9% increase in heart attack mortality during the first year of the smoking ban which was significantly different from the expected decline of 7.2%.

The meta-analysis excludes this study because it uses "nonstandard methodology." But the "nonstandard" methodology it uses is the fact that it: (1) examines heart attack death trends in an entire set of localities, rather than just in one city or state; and (2) it, unlike nearly all other studies, includes a large number of comparison localities so that the trends in places with smoking bans can be adequately compared to trends in places without bans.

Thus, the very study which uses the most appropriate methods for studying this issue is excluded.

And that makes sense, because in a study that includes the appropriate comparison groups, one is not going to find a dramatic decline in heart attacks.

In other words, when one actually compares the decline in heart attacks in the smoking ban studies with the declines occurring elsewhere, the "dramatic" declines no longer appear to be so "dramatic.":

If anything, this meta-analysis demonstrates that the observed short-term decline in heart attacks from smoking bans is not all that different from the magnitude of decline that is occurring anyway because of secular trends.

The rest of the story is that unfortunately, I believe we have resorted to shoddy science in order to try to produce evidence favorable to our cause (which I believe is a noble one: the protection of nonsmokers from the demonstrated hazards of secondhand smoke). This science, which has now abandoned the concept that a comparison group is necessary to draw valid conclusions, has deteriorated to a level that we previously would attack when we saw it being relied upon in tobacco industry studies that purported to show declines in sales associated with restaurant smoking bans.

The methodology that was once below us is now our mainstay. The only thing that has changed is that this methodology is now yielding favorable results, whereas when used by the tobacco industry to show the economic harms from smoking bans, it was yielding unfavorable results.

New Study Shows Huge Decline in Heart Attack Admissions; Demonstrates Why IOM Committee's Report on Effect of Smoking Bans is Such Poor Science

A study published in a recent issue of the journal Circulation reports that from 2002 to 2007, there was a 23.4% decline in heart attack admissions among the Medicare fee-for-service population (see: Chen J, Normand SL, Wang Y, Drye EE, Schreiner GC, Krumholz HM. Recent declines in hospitalizations for acute myocardial infarction for Medicare fee-for-service beneficiaries: progress and continuing challenges. Circulation. 2010 Mar 23;121:1322-8).

After controlling for age and other factors, the study estimates that the average decline in heart attack admissions in recent years has been 5.8% per year. According to the study authors, this secular decline in heart attack admissions is attributable to a number of factors, including improved medication for heart disease (especially the use of statins to lower cholesterol levels), improved surgical treatment for coronary artery stenosis, and decreased rates of smoking.

The Rest of the Story

This study demonstrates why the IOM committee which issued a report on the effect of smoking bans on heart attacks used such poor science in drawing its conclusion. Because of weaknesses in the underlying studies, the committee was unable to quantify the magnitude of the decrease in heart attacks associated with the implementation of smoking bans. But this new study shows that there was a large secular decline in heart attacks occurring anyway, on the order of about a 6% decline in heart attack admissions per year. If the IOM committee was unable to quantify the magnitude of the effect of smoking bans on heart attacks, then how does the committee know that the decline was significantly greater than 6%?

In fact, the IOM committee made no attempt to quantify the secular change in heart attacks that is occurring in the absence of smoking bans. And it made no attempt to quantify the degree to which heart attack declines associated with smoking bans exceed the secular declines that are occurring anyway, as documented in this new study.

In other words, the IOM committee's conclusions were based on very poor science: the absence of any control group and the failure to estimate a magnitude of effect and determine whether the confidence interval around that point estimate includes the secular rate of decline occurring in the absence of smoking bans.

This new study also demonstrates the invalidity of the conclusions of many of the individual smoking ban/heart attack studies.

For example, a study on the effect of smoking bans on heart attacks in New York State concluded that there was an 8% decline in heart attacks in the year following the statewide smoking ban. The study concludes that the smoking ban reduced heart attacks by 8%. But these new data show that in the same year (2004), heart attacks nationwide were declining by about 6%. This suggests, actually, that the New York State smoking ban had no immediate effect on heart attack rates. Certainly, in light of the 6% decline that would have been expected anyway, the finding that heart attacks declined in 8% does not support a conclusion that the smoking ban significantly reduced heart attacks (and obviously does not support the conclusion that the ban decreased heart attacks by 8%).

Nevertheless, these are data that the IOM committee relied upon to justify what now looks like a pre-determined conclusion that smoking bans result in immediate reductions in heart attacks.

As another example, consider the recent meta-analysis out of the Kansas University Medical Center which showed an 8% decline in heart attacks associated with smoking bans in 11 published studies. That 8% decline sounds impressive. Until you consider the fact that heart attacks are declining by about 6% per year anyway. I hate to have to say it, but this really amounts to junk science. The complete absence of any comparison group and the assumption that any change in heart attacks that occurs is attributable to the smoking ban. Any student in my program evaluation course who proposed a study like this without a control group would not pass the class.

The rest of the story is that there is now strong evidence that heart attacks are declining substantially due to improved medical and surgical treatment of heart disease and behavioral changes, including declines in smoking. The magnitude of the secular decline in heart attacks is roughly the same as the declines in heart attacks reported in the published studies which are being used to support the conclusions that smoking bans result in immediate, dramatic reductions in heart attacks. The chief failure of anti-smoking groups and researchers which are using these studies to support the conclusion that smoking bans were the cause of the decline in heart attacks is that they have failed to consider that heart attacks are declining substantially anyway. They have failed to compare the rates of decline associated with the implementation of smoking bans with the secular rates of decline in heart attacks. This has led to conclusions which are unsupported by scientific evidence and based on severely flawed science.

Official Data Show No Effect of England's Smoking Ban on Heart Attack Admissions During First Nine Months

Christopher Snowdon over at Velvet Glove Iron Fist has reported that data released yesterday by the National Health Service showed that England's smoking ban had no effect on the trend in the number of heart attack admissions during the first nine months that the ban was in effect.

The National Health Service has reported annual summaries of the total number of emergency room admissions for heart attacks or for admissions in which the patient subsequently suffered a heart attack. These data cover all hospitals in England; thus, there are no gaps in the data. The data cover the fiscal year, starting April 1 of the first calendar year and ending March 30 of the second calendar year. Thus, the 2007-2008 data cover the period from April 1, 2007 through March 30, 2008.

The smoking ban in England took effect on July 1, 2007. Thus, although the 2007-2008 data contain figures for three months during which the ban was not yet in effect (April, May, and June), if the ban had any dramatic effect on heart attacks (such as a 27% which is the figure which anti-smoking researchers are citing), one would expect to see some significant acceleration of the existing secular decline in heart attack admissions during the reported 2007-2008 period.

As Snowdon reports, however, there was only a 2% decline in heart attack admissions in England from 2006-07 to 2007-08, compared to a 2.8% decline in the preceding year and a 3.8% decline in the year preceding that. Thus, these data show no evidence that the smoking ban resulted in any significant, immediate decline in heart attacks.

Also as Snowdon reports, these data are very important, because the sample size is huge. Unlike the small sample sizes in studies from Helena, Pueblo, and Bowling Green, the sample size in this England study is larger than all of the published studies combined. In addition, the study covers a long period of time, not just the year before and after the smoking ban (as is the case with some of the published studies).

Further Analysis

It appears that Snowdon included all hospital discharges with a diagnosis of heart attack, both those in which the heart attack was the presenting reason for admission and those cases in which the patient suffered a heart attack subsequent to admission. While there is nothing wrong with this, someone could argue that it is only the admissions for a presenting heart attack that are relevant, because presumably, subsequent heart attacks experienced in the hospital are not triggered by secondhand smoke exposure.

I re-ran the analysis using only hospital admissions for presenting heart attacks (those which presumably might have been triggered by secondhand smoke, as hypothesized by many tobacco control researchers). The data look like this:



As one can see visually, there is absolutely no change in the trend of declining heart attack admissions in England during the first nine months during which the ban was in effect. There appears to be a relatively steady decline in heart attack admissions from 2002-2008, with no change associated with the smoking ban.

The decline in heart attack admissions from 2006-2007 to 2007-2008 was 3.7%, compared to declines of 3.7% in the preceding year and 3.8% in the year before that.

Thus, this analysis confirms that no matter how you look at it, there was no change in the rate of declines in heart attack admissions in England associated with the first nine months of the smoking ban.

The Rest of the Story

These data are important, because they demonstrate the discrepancy between population-based versus anecdotal evidence related to the immediate effect of smoking bans on heart attacks. The studies which have reported an effect of smoking bans on heart attacks have tended to be based on what are essentially anecdotal observations of declines in heart attacks in small cities. In contrast, when one looks systematically at large populations affected by smoking bans, one doesn't find a similar effect. This probably reflects publication bias. It is unlikely that researchers investigating a change in heart attacks following a smoking ban but not finding a substantial decline would publish such a finding.

These data are also important because they demonstrate that, once again, anti-smoking advocates have jumped the gun in prematurely concluding that smoking bans are lowering heart attack rates. We saw this first in Scotland, where researchers and advocates touted a 17% decline in heart attacks in a sample of Scottish hospitals using a specific diagnostic method. However, subsequent population-based data using a consistent diagnostic method revealed that the initial reports were incorrect and there was no significant acute coronary syndrome decline associated with the smoking ban.

Now, we find that anti-smoking advocates in England have jumped the gun. Last June, as I reported here, three anti-smoking groups in England seized upon anecdotal data showing a 40% decline in heart attacks in one hospital trust and used it to publicly claim that the smoking ban was resulting in a dramatic decline in heart attacks. We now know that these claims were wrong; the conclusions were premature and not borne out by the subsequent data.

We now have large population-based studies in England, Wales, and Scotland which fail to show any immediate effect of smoking bans on heart attacks. In light of these studies, which are based on very large sample sizes and which include all hospitals in the relevant areas, it is impossible to stick with the conclusion that smoking bans lead to dramatic, immediate reductions in heart attacks.

It will be interesting to see whether anti-smoking groups in England and elsewhere retract their earlier claims in light of these new data.

As John Maynard Keynes said: "When the facts change, I change my mind. What do you do, sir?"

My suspicion is that the anti-smoking groups will not change with the facts. Based on my experience, they will stick with their premature and inaccurate claims and shift the debate over to the character and integrity of those who are pointing out these conflicting data. They will not deal with the substance of these new findings. Or, at very best, they will acknowledge that the earlier conclusions may have been premature but will take no serious action to disseminate these new data. It's all for a good cause, so why should the truth actually matter?

Let me close with an admission of my own bias here. As someone who has worked for much of my career to promote workplace smoking bans, I would love to see evidence that these bans are resulting in immediate, substantial declines in heart attacks. I'd love to be able to take some credit for an immediate saving of lives. Thus, it is in my personal interest to try to interpret the findings in the most favorable light possible. However, as a scientist, I just cannot come to conclusions which are clearly not supported by the data.

While I firmly believe that in the long run, smoking bans will reduce cardiovascular disease and heart attacks due to long-term changes in smoking prevalence and secondhand smoke exposure, I do not believe there is evidence to conclude that there has been any substantial, immediate decline in heart attack deaths due to these policies.

Iowa Researchers Claim Smoking Ban Had Dramatic Effect on Reducing Heart Attacks; But Data Show No Change in Heart Attack Death Rates

According to an article on the web site of the Des Moines NBC television affiliate (WHO), University of Iowa researchers are claiming that the statewide smoking ban has had a dramatic effect on the incidence of heart disease, heart attacks, and strokes.

According to the article: "The University of Iowa says in the two years Iowa has been smoke free, Iowans reduced their risk of heart disease by staggering numbers. 'Hospital admissions related to heart disease is much less, including stroke after the Smoke Free Air Act,' says Dr. Enrico Martin of the Iowa Heart Center. Admissions have gone down 24%, according to the University of Iowa. In just months, heart attack cases are down 8%. Strokes are down 5%. It's all thanks to the simple action of moving smokers outside."

The Rest of the Story

Before even evaluating the actual data, there are two notes of caution that are important.

First, there does not appear to be any actual study. This appears to be yet another example of "science by press release." This is dangerous because if the conclusions turn out to be invalidated, it is too late to change the news. It is already out there. In fact, this story has been reported widely in the media. There is little opportunity for scrutiny of the study's findings because so far as I can tell, the methods are not publicly available.

Second, there does not appear to be any control group. The statistics being cited are simply declines in cardiovascular disease rates. Since these rates were already declining prior to the smoking ban, these statistics do not actually provide evidence that the smoking ban had any effect on cardiovascular disease rates. In fact, heart attack declines of 8% and stroke declines of 5% since the smoking ban do not appear to be much different from what one would expect in the absence of a smoking ban, given secular trends in these diseases.

Fortunately, we can objectively evaluate the researchers' claims by examining the actual data. Data on cardiovascular disease death rates in Iowa are available from the Iowa Department of Public Health web site.

The statewide smoking ban in Iowa went into effect on July 1, 2008.

Here are the trends in heart attack death rates and stroke death rates in Iowa from 1999 through 2009. The smoking ban implementation is shown in each figure. If the smoking ban had a significant effect on heart attacks or strokes, one would expect to see a substantial decline in these rates during the years 2008 and 2009.

Figure 1. Annual Heart Attack Death Rates -- Iowa, 1999-2009
Figure 2. Annual Stroke Death Rates -- Iowa, 1999-2009




These data demonstrate that the smoking ban clearly had no substantial effect on death rates for either heart attacks or stroke.

Figure 1 shows that if anything, the smoking ban was associated with an increase in the expected rates of heart attack death in Iowa. There was a slight increase in the heart attack death rate during the first year of the smoking ban's implementation, despite a trend of declining heart attacks prior to that.

Overall, there has been no change in the heart attack death rate in Iowa since the smoking ban was implemented. This is in contrast to a 39% decline in the heart attack death rate in the eight years prior to the smoking ban.

Figure 2 shows that if anything, the existing rate of decline in stroke deaths in Iowa slowed after implementation of the smoking ban. In the eight years prior to the smoking ban, the stroke death rate in Iowa declined by an average of 3.8% per year. Since the smoking ban, the stroke death rate has declined by an average of only 3.2% per year.

Clearly, I am not arguing that the smoking ban has resulted in an increase in the expected number of heart attack and stroke deaths in Iowa. What I am arguing is that the conclusions of these Iowa researchers are invalid, as they are simply not supported by the data. As is the case with most of the smoking ban - heart attack studies, these researchers are engaging in wishful thinking in the absence of rigorous scientific analysis. Once again, it appears that they are using data to try to support a pre-determined conclusion, rather than objectively examining the data.

Will these researchers, and will anti-smoking groups, acknowledge that based on these data for trends in heart attack and stroke deaths in Iowa, the smoking ban has had no effect on either? I doubt it. Because the anti-smoking groups are not interested in the truth. They are interested in disseminating pieces of data that support their pre-determined conclusions.

New Study of National Heart Attack Admissions and Mortality Finds No Evidence of a Short-Term Effect of Smoking Bans

Most Definitive Study to Date Refutes Conclusions of Many Earlier Studies and Demonstrates Why These Studies Obtained Positive Findings

A new study by researchers from the RAND Corporation, Congressional Budget Office, University of Wisconsin, and Stanford University is the first to examine the relationship between smoking bans and heart attack admissions and mortality trends in the entire nation, using national data. All previous U.S. studies only examined one particular city. In contrast, this study examined data from the Nationwide Inpatient Survey (NIS), which is nationally representative and includes 20% of all non-federal hospital discharges in the United States. The study has been published as Working Paper 14789 of the National Bureau of Economic Research Working Paper Series.

Study citation: Shetty KD, DeLeire T, White C, Bhattacharya J. Changes in U.S. hospitalization and mortality rates following smoking bans. Working Paper 14790. Cambridge, MA: National Bureau of Economic Research, 2009. The study is copyright 2009 by Kanaka D. Shetty, Thomas DeLeire, Chapin White, and Jayanta Bhattacharya.

The key conclusions of the study are as follows:

1. "In contrast with smaller regional studies, we find that workplace bans are not associated with statistically significant short-term declines in mortality or hospital admissions for myocardial infarction or other diseases."

2. "An analysis simulating smaller studies using subsamples reveals that large short-term increases in myocardial infarction incidence following a workplace ban are as common as the large decreases reported in the published literature."

The study uses state and local workplace smoking ordinance data from the American Nonsmokers' Rights Foundation tobacco control database for the years 1990 through 2004 and national data on heart attack admissions and mortality from the National Inpatient Survey (1993-2004), as well as from the Multiple Cause of Death database (1989-2004). Using a fixed effects regression model, the authors analyze outcomes (heart attack admissions and mortality) before and after the implementation of all workplace smoking bans in the nation, as identified in the ANR database.

The regression coefficient of interest represents the change in heart attack admissions or mortality associated with the implementation of a smoking ban, while controlling for secular trends in the outcome variable as well as regional differences in outcomes and regional differences in population size, number of physicians, number of hospital beds, household income, and percent of the population in the labor force.

The study also simulates the results from the comparison of all possible combinations of regions in the U.S. by examining subsets of the data, where one region is an intervention unit and the other is a comparison or control unit. The authors are therefore able to simulate what the results would be for each of the 19,406 possible comparisons of intervention and control regions in the country.

The main study result is that the regression coefficients for the smoking ban variable is not statistically significant in either the heart attack admission or heart attack mortality model, indicating that the smoking bans had no effect on either heart attack admissions or heart attack mortality.

The study estimates that workplace smoking laws reduced heart attack mortality by a non-significant 1.5%, with a 95% confidence interval of -4.8% to +1.8%. The study estimates that workplace smoking laws reduced heart attack admissions among 18-64 year-old adults by a non-significant 4.2%, with a 95% confidence interval of -10.2% to +1.7%.

Most interestingly, the simulation of all possible comparison studies of local regions in the U.S. finds that just as many studies would find an increase in heart attacks associated with smoking bans as would find a decrease in heart attacks (see Figure 2). The mean difference in heart attack admissions among all studies was 0. The exact same result was found for heart attack mortality (see Figure 3).

The paper concludes: "We find no evidence that legislated U.S. smoking bans were associated with short‐term reductions in hospital admissions for acute myocardial infarction or other diseases in the elderly, children or working‐age adults." ...

"We also show that there is wide year‐to‐year variation in myocardial infarction death and admission rates even in large regions such as counties and hospital catchment areas. Comparisons of small samples (which represent subsamples of our data and are similar to the samples used in the previous published literature) might have led to atypical findings. It is also possible that comparisons showing increases in cardiovascular events after a smoking ban were not submitted for publication because the results were considered implausible. Hence, the true distribution from single regions would include both increases and decreases in events and a mean close to zero, while the published record would show only decreases in events. Thus, publication bias could plausibly explain why dramatic short‐term public health improvements were seen in prior studies of smoking bans."

The Rest of the Story

Without a doubt, this is the most definitive study yet conducted of the short-term effects of smoking bans on cardiovascular disease.

To give you an idea of the scope of this study compared to previous ones, the Helena study involved a total of 304 heart attack admissions in one community over a period of six months. This study examined a total of 217,023 heart attack admissions and 2.0 million heart attack deaths in 468 counties in all 50 states over an eight-year period.

This study fails to find any significant short-term effect of smoking bans on heart attack admissions or heart attack mortality, although a small effect cannot be ruled out. The study refutes the claims from previous studies that smoking bans result in a short-term reduction in heart attacks in the range of 20-40%, as many anti-smoking groups are asserting.

The most important finding of this study is that there are just as many smoking ban communities in which heart attack admissions and mortality have increased in comparison with control communities as there are smoking ban communities in which heart attacks have decreased relative to control communities. The mean difference was found to be zero.

Thus, the study not only fails to find a short-term effect of smoking bans on heart attacks, but it also explains the positive findings of previous studies. What appears to be going on is what is referred to as publication bias.

What this means is the following: if one wanted an unbiased estimate of the effect of smoking bans on heart attacks, one would ideally include all communities that have enacted a smoking ban. In reality, what has occurred is that there have been what essentially amount to anecdotal studies conducted in several communities. These few studies have been published in the literature. It is possible that similar studies were conducted that failed to find an effect and that these studies were therefore not published. It is also possible that the finding of positive results in the few communities studied was essentially a result of chance. There may be other reasons why certain communities were selected for study. For example, researchers may subconsciously have a feeling that heart attacks have decreased and may want to conduct research to confirm if this is the case or not.

For whatever reason, it is apparent that the sample of communities in which this issue has been studied represents a biased sample of all possible studies that could have been conducted. When one examines, systematically, data for all regions in which smoking bans have been enacted, one fails to find a significant effect of smoking bans on either heart attack admissions or heart attack mortality.

This doesn't meant that smoking bans will not eventually result in reductions in cardiovascular disease. That will take considerable time. It just means that the conclusions of anti-smoking researchers and groups that heart attacks drop immediately upon passage of smoking bans appear to be wrong.

When I first questioned the validity of the conclusions of the Helena and Pueblo studies, I was attacked by many of my colleagues, called a traitor, and expelled from list-serves because they did not want me to spread my dissenting opinion. Now, it has become quite clear that my skepticism was well-placed to begin with. The most definitive study to date has refuted the findings of these studies.

It is important for me to point out that I never took issue with the data presented in the individual studies. There were demonstrable declines in heart attack admissions in the intervention cities. What I questioned was the conclusion that these declines were attributable to the smoking ban, rather than to random variation in the data and/or secular changes in heart attacks, which we know are declining throughout the country, even in the absence of smoking bans. There have been considerable advances in surgical and pharmaceutical treatments for coronary heart disease and these may well be the major contributing factors to the observed decline in heart attack rates.

This new research demonstrates why tobacco control researchers and groups have to be very careful in drawing causal conclusions, and why it is better to uphold high standards of scientific rigor rather than to jump to premature conclusions that may later be shown to be incorrect. Tobacco control groups, and the movement as a whole, will lose some scientific credibility because of these new findings which do not support their conclusions. But it is too late to retract those conclusions because they have already been widely disseminated through the media.

It is far better to get it correct the first time. But that requires adherence to solid science. You cannot allow advocacy concerns and goals - no matter how noble they may be - to interfere with the process of objective scientific evaluation. That is exactly what has occurred in tobacco control.

New Study Claims that New York State Smoking Ban Reduced Heart Attack Admissions by 8%

A study being released today concludes that the New York State smoking ban, implemented in July 2003, resulted in an 8% decline in heart attack hospital admissions statewide during the first year and a half it was in effect. The study was published online ahead of print today in the American Journal of Public Health (see: Juster HR, Loomis BR, Hinman TM, et al. Declines in hospital admissions for acute myocardial infarction in New York State after implementation of a comprehensive smoking ban. Am J Public Health 2007).

Although the study did not determine trends in heart attacks in smokers versus nonsmokers, it notes that there was not a significant decline in smoking prevalence associated with the implementation of the statewide smoking ban; thus, the decline in heart attacks is attributed to decreased secondhand smoke exposure among nonsmokers.

The study examined trends by month in age-adjusted hospital admission rates for acute myocardial infarction in all non-federal New York hospitals between 1995 and 2004. It used regression analysis to control for the effects of seasonal and secular trends as well as the presence of local smoking bans.

The paper concludes: "Rates of hospital admissions for AMI [acute myocardial infarction] were reduced by 8% after a comprehensive ban on smoking in work sites, including hospitality venues (e.g., bars and restaurants), in New York State. This is equivalent to a reduction of approximately 3800 AMI hospital admissions in 2004 and an estimated cost savings of $56 million. Our results show that enactment of clean indoor air laws was associated with an accelerated decline of hospital admissions and that a comprehensive statewide law had the largest effect."

The study results were first reported by the Associated Press here.

The Rest of the Story

While I do not dispute the conclusion that there was an 8% decline in hospital admissions in New York State during the second half of 2003 and all of 2004, I do not believe that these data support a conclusion that the observed decline in heart attack admissions is attributable to the statewide smoking ban.

Why? Because there is no control or comparison group. The article examines trends in heart attacks in New York, but it does not examine what happened to heart attack admissions anywhere else during the same time period.

Sure - there was an 8% decline in heart attack admissions in New York during 2004. But this doesn't mean anything unless there was not an 8% decline in heart attack admissions in other states, that did not implement smoking bans, in 2004. Without knowing what the heart attack trends were elsewhere, there is no basis to conclude that the observed decline in heart attack admissions in New York was attributable to the smoking ban.

This is essentially an uncontrolled study - a study without a control group. It represents a very weak study design for this type of analysis. Even the shoddy Bowling Green and Pueblo studies employed a comparison group to evaluate whether the observed changes in heart attacks in the cities with smoking bans were also occurring in comparable cities without smoking bans.

So what did happen in other states between 2003 and 2004? Were heart attack admissions stable in states without smoking bans, while dropping by 8% in New York state with its smoking ban in place?

Well, in South Carolina, heart attack admissions fell by 12.5% from 2003 to 2004. This is also in marked contrast to the existing trend in heart attacks in that state. Heart attack admissions were increasing by an average of 3.0% per year during the period 2001-2003 in South Carolina. So was the 12.5% decline in heart attack admissions during the same time period in South Carolina due to the absence of a statewide smoking ban?

In Nebraska, heart attack admissions fell by 28.5%from 2003 to 2004. This is in marked contrast to the existing trend in heart attacks in the state. Heart attack admissions were increasing by an average of 2.3% per year during the period 2001-2003 in Nebraska. Was this dramatic drop in heart attack admissions in Nebraska, which occurred during exactly the same period as the decline in New York, attributable to the absence of a smoking ban in the Cornhusker state?

In fact, in all other states for which data are available, heart attack admissions fell by 5.1% from 2003 to 2004. So does the decline in heart attacks in New York represent a dramatic effect of the smoking ban, or is it simply a change that would have been expected based on the secular trends occurring across the nation during the same time period?

The article in question does not allow us to answer that question. And that is precisely why its conclusion is unwarranted.

Based on the available data, it certainly appears that large declines in heart attack admissions were occurring across the nation in 2004. The observed decline in New York was far less than was observed in Nebraska and South Carolina - two states without smoking bans.

So does this mean that the absence of a smoking ban in those two states was the reason why their heart attack admissions dropped far more than in New York? Of course not. The point is that there are large year-to-year variations in heart attacks that have nothing to do with smoking bans and in order to conclude that a small decline (such as 8%) in heart attacks was due to a smoking ban, you absolutely have to show that the decline would not have occurred in absence of the smoking ban. And to do that, you need to look at what is happening in other states.

One lesson here is that even if a study is published, you still need to review it critically and you should not necessarily assume that its conclusions are valid and well-supported. And if this is what can happen with a published article, you can only imagine how much more difficult it is to accept the conclusions of a study that is neither published nor available (i.e., the Scottish smoking ban heart attack study).

As much as we might like to believe that reducing secondhand smoke exposure prevents thousands of heart attacks in a matter of months, the evidence is simply not there to support such a conclusion. By jumping the gun and drawing conclusions prematurely, I fear that we are hurting our overall scientific credibility. In the long run, that may harm the effort to promote smoking bans far more than spreading the belief that such bans are going to immediately prevent heart attacks is going to help enact these bans.

Anti-Smoking Researcher Claims that Smoking Bans Reduce Heart Attacks Within Minutes of Implementation

We're all familiar with the claims by some anti-smoking advocates that smoking bans reduce heart attacks relatively quickly after implementation, such as over a period of six months or one year.

But now, an anti-smoking researcher has claimed that these bans reduce heart attacks within just minutes of implementation.

According to an article in the Lawrence Journal-World & News, Dr. David Meyers, professor of cardiology and preventive medicine at Kansas University Medical Center and lead investigator of a new study on smoking bans and heart attacks, claimed that: "Within minutes of the ban, it is going to start having an effect on heart attacks."

Meyers was quoted as supporting his claim with the following argument: "Heart attacks are caused in large part by blood clots. With 20 minutes or so of tobacco smoke exposure, people’s blood becomes hypercoagulable and sticky and clots easily, and bam, you have a heart attack."

The study being reported is a meta-analysis of 11 previously published studies that examined the effect of smoking bans on heart attack rates in specific communities (such as Helena, Pueblo, and Bowling Green) or in countries with national smoking bans (such as England, Italy, and Scotland). The meta-analysis found that: "Using 11 reports from 10 study locations, AMI risk decreased by 17% overall (IRR: 0.83, 95% CI: 0.75 to 0.92), with the greatest effect among younger individuals and nonsmokers." The study concluded: "Smoking bans in public places and workplaces are significantly associated with a reduction in AMI incidence, particularly if enforced over several years."

The Rest of the Story

What readers need to understand is that a meta-analysis is only as good as the individual studies that go into it. If the individual study conclusions are invalid, then the meta-analysis will be invalid as well. This is exactly the case with the present study.

I have previously analyzed each of the published studies on smoking bans and heart attacks and explained why the conclusions of these studies are invalid. You can't just combine the studies in a meta-analysis and argue that suddenly the conclusion becomes valid. The meta-analysis does not account for the severe flaws in these studies, including the failure to adequately rule out the possibility that the observed declines in heart attacks merely reflected a combination of random variation plus an already declining secular trend in heart attacks over time.

But the most telling fact about this meta-analysis is that it fails to incorporate any control or comparison population. In other words, it includes studies even if they did not employ a comparison group. And in the studies that did include a comparison group, it appears to throw out the data regarding the comparison group.

What this means is that the meta-analysis is not designed to estimate the effect of smoking bans on heart attacks. What it is designed to do is to determine the change in the incidence of heart attacks over the time period in these studies. What the meta-analysis demonstrates is that across all study populations, there was a significant decline in heart attack rates.

But we already knew that. For many reasons, including better treatment for heart disease (both surgical treatment and medications), heart attack rates have generally been declining, even in the absence of smoking bans. The relevant question for the meta-analysis should have been: are these observed declines due to the smoking ban? Instead, the meta-analysis simply asked the question of whether there was or was not a decline in the first place? This is useful information, as it confirms our a priori impression that rates have been declining, but it offers no evidence that the declines are due to smoking bans, as opposed to other changes, such as improved diagnosis of minor coronary events, earlier diagnosis of unstable angina, improved surgical treatment (angioplasty) for coronary artery disease, and greatly improved medical treatment (e.g., statins to bring cholesterol levels under control).

In essence, what we have here is a meta-analysis of studies without comparison groups!

I don't see how you can possibly include in this meta-analysis studies that failed to include a comparison group. There's simply no way to know whether the observed decline in heart attacks was attributable to the smoking ban or not.

In short, the meta-analysis presents the wrong analysis. It should not present the estimated change in heart attack rates before and after the smoking bans. We know that the rate is going to go down significantly because of the known secular trends in heart attacks, which are declining everywhere, even in the absence of smoking bans.

Instead, the correct analysis would have been to examine the individual estimates of the difference between the declines in heart attack rates in intervention (i.e., smoking ban) versus comparison communities or countries.

As my readers know, I strongly support workplace smoking bans. Nevertheless, I believe they should be supported based on valid scientific conclusions, not on junk science conclusions such as those in this article.

Another telling finding in the meta-analysis is that the studies which found the large declines in heart attacks (and which drive the findings of the whole meta-analysis) were the studies of the smallest communities, where there is the greatest variation in heart attack rates. The larger studies, with very large populations, failed to find substantial effects.

This suggests that the conclusions are due primarily to a few anomalous findings in small communities with very few heart attacks. When one examines the results among a large population, one fails to find the reputed effects.

The meta-analysis itself reports that there was no effect of the smoking ban in either the state of New York (the largest population studied) or the country of Italy (the second largest population studied). The results appear to be entirely driven by the findings in Helena, Monroe County, and Pueblo, which include two of the smallest populations studied (there were only 17 heart attacks in Monroe County to begin with and only about 40 in Pueblo during the post-ban period).

The most interesting aspect of this story, however, is that even if we stipulate for the sake of argument that the study conclusions are correct, what the results would show is that over a period of time -- months to years -- there is a decline in heart attacks. The study does not support the assertion that there is a decline in heart attacks within minutes of a smoking ban.

I have to take issue with the explanation for this immediate effect. As put by one of the study authors: "Heart attacks are caused in large part by blood clots. With 20 minutes or so of tobacco smoke exposure, people’s blood becomes hypercoagulable and sticky and clots easily, and bam, you have a heart attack."

If this statement were true, then we would see large numbers of previously healthy people dropping dead of heart attacks in smoky bars after 20 minutes. If it is true that your blood clots easily and bam you have a heart attack, then many healthy people going into a smoky bar would leave the bar after 20 minutes in an ambulance. We just don't see that happening (except, perhaps, for those who severely overindulge to the point of alcohol intoxication -- mostly college freshmen).

The truth is that brief secondhand smoke exposure is likely to trigger a heart attack only in people with severe existing coronary artery disease. And for such individuals, there are so fragile that any exposure which increases platelet aggregation and causes endothelial dysfunction -- is also likely to trigger a heart attack. There is no mechanism I know of by which secondhand smoke is the only exposure that can trigger a heart attack in some who is brittle enough so that a mere 20 minute exposure to tobacco smoke is going to trigger a heart attack. The same hypercoagulability and endothelial dysfunction is also caused by eating high-fat foods and even by mental stress. It doesn't follow that you are going to prevent this person from having a heart attack merely by asking them to avoid exposure to secondhand smoke. Moreover, there is simply no scientific evidence to support the assertion that by avoiding secondhand smoke exposure, we will prevent heart attacks among individuals with severe coronary artery disease.

The rest of the story is that anti-tobacco researchers and groups are making ridiculous, highly exaggerated, and scientifically unsupported claims in order to try to justify smoking bans. While I support the very smoking bans which these groups are promoting, I do not support the junky science and wildly exaggerated and misleading claims that are being made to the public.