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.

Anti-Smoking Researchers Argue that Mathews Study Shows Significant Effect of Smoking Bans on Acute MI; Lack of Scientific Rigor Apparent

Last week, I reported on a study, by Dr. Robin Mathews of the Duke Clinical Research Institute, that examined rates of heart attacks among persons ages 65 and older in 74 cities across the U.S. which adopted strong smoking bans during the period 2000-2008. The researchers compared the heart attack rate in each city during the year before and after the smoking ban was implemented.

When Mathews included all 74 cities that enacted smoking bans during the study period (regardless of strength of the ordinance), he found an overall decline in heart attack rates of just 3%. However, when the analysis was restricted to the 43 cities whose newly enacted ordinances represented a significant increase in protection from secondhand smoke, Mathews reports that there was absolutely no change in the heart attack rates across the sample of cities. A figure shows that heart attacks decreased in some cities and increased in others. All told, heart attack rates decreased by an insignificant 1% among these 43 cities.

Based on these findings, I pointed out that the study fails to support the conclusion - being widely disseminated by anti-smoking groups - that smoking bans result in dramatic, immediate reductions in hospital admissions for acute myocardial infarction. The Institute of Medicine report, for example, cites a reduction of 17% in heart attacks across the studies that it evaluated.

Now, a number of anti-smoking researchers, presumably in response to my blog post, have argued that the Mathews study actually supports the prior research, demonstrating that while small (3%), there is a "significant effect" of smoking bans on heart attacks within one year of implementation of these laws.

The Rest of the Story

There are two reasons why the argument disseminated by these anti-smoking advocates is scientifically flawed.

1. The argument ignores the relevant analysis, relying on the result of an essentially meaningless analysis.

First, it ignores a major result of the study, choosing instead the one result which found a significant effect but ignoring what is actually the most relevant analysis, which failed to find an effect.

The analysis of all 74 cities, which did find a significant decline in heart attacks of 3%, included cities that had enacted ordinances that failed to "meaningfully" increase protection from secondhand smoke. Thus, these cities were misclassified. Rather than being in the intervention group, they should have been considered to be communities that did not increase their secondhand smoke protection.

The relevant analysis is the analysis of the 43 cities in which the level of protection from secondhand smoke meaningfully increased after implementation of the smoking ordinance. It was that analysis which found only a 1% (non-significant) decline in heart attacks.

If an ordinance provides no meaningful increase in protection from secondhand smoke, then why would one classify it as an intervention community?

2. The study lacks a control or comparison group.

Second, because the study lacks a control group, all one can conclude from it is the change in heart attacks from before to after the ordinances. One cannot infer that this change was due to the ordinance because there is no evidence that these declines exceed those that were occurring simultaneously in communities without smoking bans.

Even if we accept the results of the full analysis of 74 cities (a 3% decline in heart attacks overall in these cities), the only way one could credibly conclude that this 3% decline was due to the smoking bans is to compare this decline to that in communities without smoking bans and show that the heart attack decline in the intervention (i.e., smoking ban) communities was significantly greater.

The rest of the story is that heart attack rates during the study period declined substantially throughout the United States, even in communities without smoking bans, and the average annual rate of decline in heart attack admissions among 65+ year olds during the study period appears to be in the approximate range of 3% per year.

Based on data from the Health Care Utilization Project, I calculated the year-to-year declines in heart attack admissions among persons ages 65 and up nationally for the years 2000 to 2006 (more recent data are not yet available on admissions). The average annual decline in admissions was 3.4%.

Thus, the observed decline in heart attacks in the 74 communities that enacted smoking bans during the study period appears to be a little lower than the decline in heart attacks that occurred nationally, with or without smoking bans in place.

To demonstrate how "meaningless" the observed 3% decline in heart attacks is in the context of a control group (the United States as a whole), the annual decline in heart attack admissions among 65+ year-olds during the more recent years was as follows:

2002-2003: -4.5%
2003-2004: -8.0%
2004-2005: -7.0%
2005-2006: -4.5%

Without even seeing these data, the anti-smoking researchers have nevertheless concluded that a mere 3% reduction in heart attacks in a one-year period is a significantly greater decline than what was occurring nationally anyway based on secular trends, in the absence of a smoking ordinance.

Of course, what we really need as a comparison group are cities that are similar to those which enacted smoking bans in other ways, but did not themselves enact smoking bans. The national data include cities with and without smoking bans.

My point is simply that without the comparison data from communities that did not enact smoking bans, one cannot possibly conclude that the observed 3% decline in heart attacks in the cities that enacted smoking bans was greater than what would have occurred in the absence of these bans.

The Mathews study certainly cannot be used to support the contention that smoking bans result in a significant short-term decline in heart attacks. At best, all it can support is the conclusion that in the cities which enacted smoking bans, there was an overall average decline of 3% in heart attacks during the first year of implementation. This 3% decline could be more than, less than, or the same as what would have occurred in the absence of the smoking bans (i.e., the observed change in heart attacks during the same period of time in comparison cities without smoking bans).

While I am a passionate supporter and promoter of smoking bans, I do my best to try not to let that interfere with my interpretation of the scientific evidence. As is hopefully apparent to regular readers, I will report findings to the public, even if they are "unfavorable" to us in tobacco control.

I want to close by emphasizing that in the long-term, smoking bans will almost certainly reduce heart disease (and therefore heart attacks). The question is whether this effect can and will happen immediately (within one year). Even if we fail to see an effect on heart attacks within one year, this does not argue against the enactment of smoking bans. In fact, even if smoking bans had no long-term effect on heart disease, the respiratory effects of secondhand smoke alone would be enough to support protecting the public from secondhand smoke exposure.

I do hope, however, that we in tobacco control will base our support of smoke-free policies on credible scientific evidence, rather than on a study like the Mathews one which lacks a control group and makes the conclusion being disseminated by these researchers an unsupportable one.

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 Concludes that State Smoking Bans Significantly Reduce Heart Attacks

A new study, published recently in the online journal Public Health, concludes that statewide smoking bans have led to a significant reduction in the prevalence of self-reported heart attacks.

See: Lippert WC, Gustat J. Clean Indoor Air Acts reduce the burden of adverse cardiovascular outcomes. Public Health 2012; 126:279-285.

In the study, the authors used state-specific data from the Behavioral Risk Factor Surveillance System (BRFSS) surveys to determine the prevalence of self-reported heart attacks one year prior to the implementation of a statewide smoking ban and in 2009, after the smoking ban had been in effect. There were 17 states included in the study. Each had enacted a statewide smoking ban in either 2006, 2007, or 2008. For a smoking ban enacted in 2006, data from the 2005 BRFSS would be compared to data from the 2009 BRFSS. For a smoking ban enacted in 2008, data from the 2007 BRFSS would be compared to data from the 2009 BRFSS.

In this way, the study was able to compare changes in the prevalence of self-reported heart attacks among adults from before to after the state smoking bans in these 17 states.

The results were reported as follows: "Ten of the 17 states/territories (58.8%) were found to have a significant decrease in the prevalence of CHD/angina (Arizona, District of Columbia, Hawaii, New Hampshire, New Jersey, New Mexico, Pennsylvania) or AMI (District of Columbia, Hawaii, Iowa, Minnesota, New Hampshire, New Jersey, Puerto Rico) between baseline and 2009. Two states/territories (11.8%) had a significant increase in the prevalence of CHD/angina (Colorado and Louisiana) between baseline and 2009. Four states (23.5%) had an increase in the prevalence of AMI (Colorado, Louisiana, Nevada, Pennsylvania) between baseline and 2009, but these increases were not significant."

Based on these results, the paper concludes: "The data suggest that CIAAs reduce the prevalence of current smokers and adverse cardiovascular outcomes between 1 and 4 years following implementation (average time between baseline and 2009 was 3.06 years). State/territory-wide reductions in the prevalence of CHD/angina or AMI were observed 1 year (Iowa and Pennsylvania), 2 years (Arizona, District of Columbia, Minnesota, New Hampshire, New Mexico, Puerto Rico) and 3 years (Hawaii, New Jersey, Ohio) after CIAA implementation. Overall, 10 of the 17 states/territories (58.8%) had a decrease in the prevalence of CHD/angina or AMI. ... In conclusion, state/territory-wide CIAAs appear to significantly reduce the prevalence of CHD/angina, AMI, and current and former smokers in the immediate period following CIAA implementation (1–4 years)."

The paper's abstract concludes: "State/territory-wide CIAAs are beneficial in reducing adverse cardiovascular health outcomes in the short term. The prevalence of AMI, CHD/angina, and former and current smokers decreased significantly following CIAA implementation."

The Rest of the Story

There are two major flaws of this study which render its conclusion invalid.

1. There is no control group.

First, there is no control group. The study simply compares changes in self-reported prevalence of heart attacks in states with smoking bans from approximately 2006 to 2009. The study finds that in some states, there was a significant decline during this three-year period. However, without knowing what happened in states without a smoking ban, it is impossible to attribute this change in heart attack prevalence to the smoking ban. One needs to know what was the change in heart attack prevalence from 2006 to 2009 in states that did not enact smoking bans.

The study does not report this information. However, from the Health Care Utilization Project (HCUP) data, we can obtain the changes in hospital discharges with a primary diagnosis of heart attack (i.e., incident heart attacks) in states without smoking bans between the years 2006 and 2009. Here are the data for all states without smoking bans in the HCUP database for which there are data for these years (the last column shows the percentage change from 2006 to 2009):

State	2006	2009
SC	9825	8890	-9.5
OK	8687	8030	-7.6
AR	7192	6837	-4.9
KY	12839	12444	-3.1
MO	15198	14310	-5.8
TN	17229	16493	-4.3
WV	6645	5891	-11.3
TOTAL	77615	72895	-6.1

From this table, one can see that in every state without a smoking ban for which HCUP data are available during the study period, there was a substantial decline in heart attacks, ranging from a decline of 3.1% in Kentucky to a decline of 11.3% in West Virginia. Overall, the decline in heart attacks in these 7 states without smoking bans was 6.1% from 2006 to 2009.

Therefore, how can this study conclude that the decline in self-reported heart attacks in the 17 smoking ban states from 2006 to 2009 was different than what would have been observed in the absence of these bans. Clearly, there is a secular trend of declining incident heart attacks in the United States that is independent of statewide smoking bans.

Given this baseline secular trend, the study cannot conclude that the observed declines in self-reported heart attacks observed in the 17 study states were attributable to the smoking bans in those states, as opposed to simply reflecting underlying secular trends, which are readily observable in states without such smoking bans.

2. The study conducts the wrong statistical analysis.

The study's conclusion that the smoking bans led to a significant reduction in heart attacks is based on the observation that in 10 of the 17 states, the prevalence of heart attacks declined. Of course, another way to look at this is to say that in 7 of the 17 states, the prevalence of heart attacks increased. The real question is this: if there were no true change in heart attacks, what percentage of the time would 10 out of 17 states show a decrease in heart attacks by chance alone?

Think of it this way. Suppose you flip a coin 17 times and come up with 10 heads. Can you conclude that this is not a fair coin, and that it must be weighted more heavily towards heads?

Well one can calculate the probability of obtaining 10 or more heads out of 17 coin tosses with a fair coin. Using the binomial distribution, one can determine that if one flips a fair coin 17 times, the chances of getting at least 10 heads is 31.5%.

Thus, by chance alone, if one were to examine changes in heart attack prevalence in 17 states, one would find that heart attacks decreased in 10 of those 17 states 31.5% of the time (if there were actually no true change in heart attacks). This is far beyond any reasonable level of statistical significance (which is usually set at about 5%).

Thus, the reasoning used by the study to conclude that there was a significant effect of the smoking bans on heart attacks is flawed. The truth is that the observed results (10 out of 17 states showing a decline in heart attacks) would occur by chance about 31% of the time, in the absence of any effect of smoking bans on heart attacks.

A more powerful statistical analysis in this situation would be to calculate the change in heart attack prevalence for each of the 17 states and then determine whether the average change in heart attacks across the states differs significantly from zero, based on standard errors that take into account the total number of observations (i.e., states).

If one conducts this analysis, one will find that the average change in heart attack prevalence among the 17 states is -0.34 percentage points. However, the standard deviation is 0.42 percentage points. Using these data, we can construct a 95% confidence interval for the change in heart attack prevalence, which is [-0.13 to -0.56]. Thus, it turns out that the change in heart attack prevalence is statistically significant.

From this study, then, one can conclude that there was a small, but significant decline in heart attacks in the 17 intervention states. However, in the absence of data from the control states, one cannot conclude that this small decline in heart attack prevalence was attributable to the smoking bans in these states.

Institute of Medicine Report's Conclusions on Smoking Ban Effects are Defied By Its Own Assertions; Study Conclusions, Press Release Severely Biased

A new report from the Institute of Medicine's Committee on Secondhand Smoke Exposure and Acute Coronary Events, entitled "Secondhand Smoke and Cardiovascular Effects: Making Sense of the Evidence," concludes that smoking bans result in a nearly immediate and significant decrease in heart attacks, not only among smokers but among nonsmokers as well. The committee also concluded that brief exposure to secondhand smoke causes heart attacks and refused to qualify its conclusion by noting that such an effect is substantial only in those with severe existing heart disease.

According to the press release: "Smoking bans are effective at reducing the risk of heart attacks and heart disease associated with exposure to secondhand smoke, says a new report from the Institute of Medicine. ... 'It's clear that smoking bans work,' said Lynn Goldman, professor of environmental health sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, and chair of the committee of experts that wrote the report. 'Bans reduce the risks of heart attack in nonsmokers as well as smokers.'"

The Rest of the Story

Unfortunately, this report might just as well have been called: "Secondhand Smoke and Cardiovascular Effects: Making Nonsense of the Evidence."

The reason for this assertion is two-fold:

First, the conclusions of the report are completely defied by the committee's own assertions that are presented in the actual report.

Second, the report draws conclusions that are essentially meaningless from an epidemiologic and clinical perspective. What the report does is take important questions and distort them so much that the answers no longer have any meaning.

Let me address each of these problems in turn.

To see what I mean about the conclusions of the report not being consistent with the report itself, consider first what the report concludes about the ability, based on the existing evidence, to estimate the magnitude of the effect of smoking bans on heart attack rates.

The report asserts as follows: "The committee was unable to determine the magnitude of effect on the basis of the 11 studies, because of variability among and uncertainties within them. Characteristics of smoking bans vary greatly among the locations studied and must be taken into account in reviewing results of epidemiologic studies. Those characteristics include the venues covered by the bans (such as offices, other workplaces, restaurants, and bars) and compliance with and enforcement of the bans. Other differences or potential differences among the studies include the length of followup after implementation, population characteristics (such as underlying rates of acute coronary events and prevalence of other risk factors for acute coronary events, including diabetes and obesity) and size, secondhand-smoke exposure levels before and after implementation, preexisting smoking bans or restrictions, smoking rates, and method of statistical analysis. The time between implementation of a ban and decreases in secondhand smoke and acute cardiovascular events cannot be determined from the studies, because of the variability among the studies and indeed the difficulty of determining the precise time of onset of a ban."

The report also asserts: "However, because of the weaknesses discussed above and the variability among the studies, the committee has little confidence in the magnitude of the effects and, therefore, thought it inappropriate to attempt to estimate an effect size from such disparate designs and measures."

In other words, what the committee is saying is they have no confidence in making any estimate of the size of an effect of smoking bans on heart attack rates. Another way to say that is this: the committee has no idea of what the effect of smoking bans on heart attacks is.

If you can't even estimate the magnitude of an effect - if you have no confidence in even providing an estimate - then you are hardly in a position to conclude that there is a significant effect of smoking bans on heart attacks, an effect which exceeds random variation combined with the known secular decline in heart attack rates.

Think about this: we know for a fact that heart attack rates are declining substantially, even in the absence of smoking bans. These declines are in part attributable to improvements in the treatment of coronary disease and also to improved medications, such as the statin drugs which are effective in controlling cholesterol levels. When we see a decline in heart attacks after a smoking ban, we need to determine whether the magnitude of that decline is greater than one would expect in the absence of the smoking ban. In other words, does the observed decline exceed the rate of decline one would expect from the secular changes alone?

In order to make such a determination, one needs to quantify the magnitude of the decline in heart attacks. If we can't even estimate, with any confidence, what the magnitude of the decline in heart attacks is, then we are in no position to conclude that we know that the decline is greater than what would have been observed in the absence of the smoking ban. We can't conclude that the observed decline in heart attacks associated with smoking bans has been due to the smoking ban, rather than to the rather drastic declines in heart attacks that have been occurring anyway due to improvements in medical treatment.

Epidemiology is all about estimating the magnitude of effects. Simply judging whether an association works in one direction or the other is not particularly meaningful, especially in this situation where we know a priori that smoking bans do not increase heart attacks.

Now this is where my 2nd observation comes in. By answering the question: do smoking bans reduce or increase heart attacks, the report is actually making nonsense out of the evidence. Of course smoking bans don't increase heart attacks. The question is: what is the magnitude of the effect.

The committee recognizes that the existing studies are so seriously flawed that one has no confidence in being able to judge the effect size. But instead of concluding that the evidence is insufficient, they go ahead and conclude that smoking bans significantly reduce heart attacks anyway.

A second example is the press release's conclusion about whether the observed reductions in heart attacks occur in smokers or nonsmokers. The report asserts: "Only two of the studies distinguished between reductions in heart attacks suffered by smokers versus nonsmokers." Later, it emphasizes this point: "In most of the studies, the portion of the effect attributable to decreased smoking by smokers as opposed to decreased exposure of nonsmokers to secondhand smoke cannot be determined."

Clearly, this is not sufficient evidence to draw a conclusion about whether the observed reductions in heart attacks are due to reduced active smoking or reduced tobacco smoke exposure among nonsmokers.

Nevertheless, the press release states: "Bans reduce the risks of heart attack in nonsmokers as well as smokers."

So much for requiring evidence before drawing a conclusion.

Perhaps the problems I am discussing are most evident in the report's conclusion regarding the effects of brief secondhand smoke exposure on heart attack risk. Based on the evidence, no one would deny that a brief exposure might trigger a heart attack in a person with severe existing coronary artery disease.

But the report goes beyond that in its conclusion. It states that brief secondhand smoke exposure may trigger heart attacks, but without qualifying that statement to make it clear that it refers specifically to people who have coronary disease. Instead, it makes it sound like a healthy person could walk into a smoky bar, sit down for 20 minutes, and keel over from a heart attack.

Why is this qualification not added to the study conclusion?

I believe it's because the report aims to be more sensationalistic and scare people into thinking that they could drop dead from a heart attack from a brief tobacco smoke exposure, even if they are healthy.

But failing to qualify the statement turns the conclusion from being accurate to being inaccurate, from being truthful to being misleading.

What it really means is that a political goal, not a purely scientific one, is driving the report's conclusion regarding the acute cardiovascular effects of tobacco smoke exposure. I find this unfortunate because it really taints the scientific integrity of the tobacco control movement.

I should probably add that if you read the report carefully, it actually makes the assertion that brief secondhand smoke exposure can appreciably increase the risk of heart attack among healthy people. The report states: "The data provide evidence that it is biologically plausible for secondhand smoke to be a potential causative trigger of acute coronary events. The risk of acute coronary events is likely to be increased if a person has preexisting heart disease."

I read this as asserting that brief secondhand smoke exposure triggers heart attacks among people with and without existing heart disease, but that the risk is higher for those with existing heart disease. I do not believe there is any evidence to suggest that such an assertion is true. The report provided no evidence that a healthy person may suffer a heart attack from a mere 20 to 30 minutes of secondhand smoke exposure.

There is one other major problem with the report that deserves mention, especially since I think it indicates a bias of the report.

The report claims to have reviewed unpublished data and to have attempted to identify unpublished studies that might have found no effect of smoking bans on heart attacks. The report states that "no such studies were identified." I find this difficult to believe, especially since I was a reviewer of the report and I made the committee aware of several unpublished analyses which documented no significant effect of smoking bans on heart attacks. Such studies were conducted in England, Scotland, and Wales. Furthermore, a large but unpublished study of all communities in the United States reported no effect of smoking bans on heart attacks, but this study was ignored by the report.

Note that the latter study, the largest of its kind, concluded that: "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."

It is unfortunate that this study was ignored. I don't see how the review can be considered to be comprehensive if it threw out or ignored all the studies that failed to find an effect, but included, without question, all studies that found an effect, even if these studies failed to include a comparison group which is crucial to being able to infer whether the observed decline in heart attacks was attributable to the smoking ban.

Finally, I want to make it very clear that I am not impugning the integrity of the committee or any of its members. I don't think they've done anything wrong. I just think that the report is biased and that subconsciously, there was some sort of pressure operating which led to the report drawing conclusions that were not appropriate given the report's own assertions and review of the evidence. I also think this bias led to the report distorting the questions which it asked and failing to directly answer the questions (rather than distorting them so that the "answer" came out more "favorably").

Error Disclosed in Meta-Analysis of Smoking Bans' Effect on Heart Attacks: Will Anti-Smoking Groups Report the Error?

In October, Dr. David Meyers and colleagues published a paper in the Journal of the American College of Cardiology in which they reported the results of a meta-analysis of published studies on the effect of smoking bans on heart attack admissions. The paper concluded that smoking bans were associated with a 17% decline in heart attack admissions in the 11 studies that were reviewed.

These results were disseminated widely in the media and heavily touted by anti-smoking groups as supporting the conclusion that smoking bans immediately and dramatically reduce heart attacks and that brief exposure to secondhand smoke in bars and restaurants causes a large number of heart attacks.

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 the study 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."

I criticized the study's conclusions on a number of grounds, including the fact that no control or comparison groups were examined, so that there was no way to determine whether the 17% decline in heart attacks might have occurred anyway, even in the absence of the smoking bans. I also noted the severe weaknesses in the underlying studies and the fact that the review only included published data, while ignoring a large body of unpublished data which refutes the study conclusion, while employing much larger sample sizes and thus having greater validity.

The Rest of the Story

As it turns out, the study findings were due to a careless error. In the original study, the authors had inadvertently reported the Pueblo study has having reported a 70% reduction in heart attacks (a result that is completely implausible and clearly should have been noticed as having been in error). Instead, that study actually reported a 34% reduction in heart attacks. The meta-analysis authors published a correction in which they re-analyzed the correct data.

It turns out that the 11 studies did not find a 17% reduction in heart attacks, but only found an 8% reduction in heart attacks.

This level of decline in admissions for heart attacks is obviously not significantly different from the levels of decline in heart attacks that are being observed in the absence of smoking bans, which have varied between 5% and 10% per year in many communities.

For example, in the United States as a whole, heart attack admissions declined by 8.2% in 2004. The decline of 8% in communities/nations with a smoking ban is comparable to this. Therefore, the meta-analysis result fails to provide any evidence that the smoking bans resulted in a decline in heart attacks.

The failure of the meta-analysis to include any comparison groups is a fatal flaw that is indicative of very poor analytic methods. For example, we know that hospital admissions for heart attacks decreased by 28.5% in Nebraska in 2004 and by 12.5% in South Carolina during the same year. These are states without statewide smoking bans or even local smoking bans in place during 2004. Thus, it is obvious why it is essential to include a control or comparison group in conducting a meta-analytic review of these studies. One needs to be able to separate out the effect of the smoking ban from the secular decline in heart attacks that is being observed anyway.

But even without the comparison group analysis, the meta-analysis - as it stands - fails to provide any evidence that smoking bans resulted in a decline in heart attacks. The observed 8% decline in heart attack admissions could easily be indicative of the underlying decline in heart attacks, which was at exactly the same level (8%) in 2004, which is the approximate time of many of the studies included in the meta-analysis.

Predictably, this correction of the error in the meta-analysis has received no media attention. No effort was apparently made to disseminate the revised results. Of course not, because they are less favorable to anti-smoking groups. Remember, it's not the truth that 's important, it's whether the results are favorable or not.

So once again, I offer a prize to any anti-smoking group which originally disseminated the results of the meta-analysis - reporting a 17% decline in heart attacks associated with smoking bans - and which now corrects that error and publicly disseminates the correct finding: that the actual decline was only 8%, which is not significantly different from what is occurring anyway in the absence of smoking bans.

Since I am so sure that no groups will respond to this challenge, I will increase the size of the award to $200.

The money is not at risk because these anti-smoking groups are really not interested in scientific rigor and accuracy. They are interested in presenting favorable data which supports their agenda. While I largely share and support that agenda, I do not share and support the tactic of misleading the public in order to achieve these goals.


(Thanks to Klaus K. for the tip)

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.

Americans for Nonsmokers' Rights Accuses the Rest of the Story Author of Being Unprofessional for Sharing his Opinion About Smoking Ban/Heart Attack Studies; Attempt to Quell Dissenting Opinion is Unsuccessful

In an apparent attempt to quell dissent on the issue of whether smoking bans lead to immediate, dramatic reductions in heart attacks, Americans for Nonsmokers' Rights (ANR) has accused me of acting unprofessionally by sharing my opinion about the lack of scientific evidence to support the group's conclusion that smoking bans have such effects.

On Friday, I criticized an ANR document which purports to share with the public a list of the U.S. studies examining the short-term effects of smoking bans on heart attack rates. Under the category of "United States," ANR lists just one study - a study by Lippert and Gustat which concluded that smoking bans do lead to immediate reductions in heart attacks. I note in my commentary that ANR omitted from its list the two largest studies conducted in the U.S., both of which failed to find a short-term effect of smoking bans on heart attacks.

In response to my commentary, ANR wrote me and accused me of acting unprofessionally by sharing these opinions on my blog. ANR wrote: "Your approach to 'discussing' these sorts of issues continues to be exceedingly unconstructive and unprofessional."

The Rest of the Story

To translate ANR's message to me: "It is unprofessional of you to share your dissenting opinion publicly on your blog. You are free to disagree, but not to express your disagreement with others. That is unprofessional behavior."

This is a strange interpretation of academic freedom, free speech, and scientific integrity.

By the way, I don't begrudge ANR's disagreement, as it may exist, with my opinions regarding the scientific evidence related to the short-term effects of smoking bans on heart attacks. I would have been happy to discuss with ANR the scientific evidence and its strength, as well as the analytic and statistical issues involved with the scientific interpretation of these studies.

However, ANR's note was not simply a statement of scientific disagreement. It was an accusation of unprofessional behavior on my part. In other words, it was an attack on my personal character and integrity.

As I have noted before, this is a common tactic in the anti-smoking movement for dealing with dissent. Rather than deal substantively with the scientific issues, you attack the dissenter, trying to discredit him personally. This is also a tactic that I observed tobacco companies using in years past.

This is mildly ironic, as it was my disagreement with and discomfort with this very tactic that led to my resigning from the ANR Board of Directors in the first place. I now see that they haven't come very far since that time.

This story simply reinforces (and demonstrates) the argument I made in my commentary: "This is not science, it is politics. ANR has ceased being a science- or policy-based organization and has entered the political realm. ... It's sad for me to see the deterioration of the scientific integrity of the tobacco control movement, and it is particularly disheartening to see our organizations adopting many of the same tactics that we attacked the tobacco companies for using in years past."

While it would not be surprising to see ANR using this tactic against its "opponents" (and I have documented how ANR indeed uses this tactic against opposing groups), it is unfortunate that the organization has to resort to using this tactic against its own colleagues in the tobacco control movement.

ANR's response also demonstrates how it is cherry-picking the studies which have favorable results and intentionally excluding studies that don't have favorable results. The response argued that the Shetty et al. study should not included because of several methodological weaknesses, including the fact that it defined all smoking restrictions as "smoking bans" even if they were only partial bans. That's fine, but if one is going to restrict studies that have methodological weaknesses, then one has to do that with all studies, not just with the ones that have unfavorable findings.

In fact, the Lippert and Gustat study - which ANR cites as its only U.S.-based multi-state study, is the weakest of all studies on smoking bans and heart attacks. As I have pointed out previously, there are two major flaws of this study which render its conclusion invalid.

1. There is no control group.

The study simply compares changes in self-reported prevalence of heart attacks in states with smoking bans from approximately 2006 to 2009. The study finds that in some states, there was a significant decline during this three-year period. However, without knowing what happened in states without a smoking ban, it is impossible to attribute this change in heart attack prevalence to the smoking ban. One needs to know what was the change in heart attack prevalence from 2006 to 2009 in states that did not enact smoking bans.

The study does not report this information. However, from the Health Care Utilization Project (HCUP) data, we can obtain the changes in hospital discharges with a primary diagnosis of heart attack (i.e., incident heart attacks) in states without smoking bans between the years 2006 and 2009. Here are the data for all states without smoking bans in the HCUP database for which there are data for these years (the last column shows the percentage change from 2006 to 2009):

State	2006	2009
SC	9825	8890	-9.5
OK	8687	8030	-7.6
AR	7192	6837	-4.9
KY	12839	12444	-3.1
MO	15198	14310	-5.8
TN	17229	16493	-4.3
WV	6645	5891	-11.3
TOTAL	77615	72895	-6.1

From this table, one can see that in every state without a smoking ban for which HCUP data are available during the study period, there was a substantial decline in heart attacks, ranging from a decline of 3.1% in Kentucky to a decline of 11.3% in West Virginia. Overall, the decline in heart attacks in these 7 states without smoking bans was 6.1% from 2006 to 2009.

Therefore, how can this study conclude that the decline in self-reported heart attacks in the 17 smoking ban states from 2006 to 2009 was different than what would have been observed in the absence of these bans? Clearly, there is a secular trend of declining incident heart attacks in the United States that is independent of statewide smoking bans.

Given this baseline secular trend, the study cannot conclude that the observed declines in self-reported heart attacks observed in the 17 study states were attributable to the smoking bans in those states, as opposed to simply reflecting underlying secular trends, which are readily observable in states without such smoking bans.

2. The study conducts the wrong statistical analysis.

The study's conclusion that the smoking bans led to a significant reduction in heart attacks is based on the observation that in 10 of the 17 states, the prevalence of heart attacks declined. Of course, another way to look at this is to say that in 7 of the 17 states, the prevalence of heart attacks increased. The real question is this: if there were no true change in heart attacks, what percentage of the time would 10 out of 17 states show a decrease in heart attacks by chance alone?

Think of it this way. Suppose you flip a coin 17 times and come up with 10 heads. Can you conclude that this is not a fair coin, and that it must be weighted more heavily towards heads?

Well one can calculate the probability of obtaining 10 or more heads out of 17 coin tosses with a fair coin. Using the binomial distribution, one can determine that if one flips a fair coin 17 times, the chances of getting at least 10 heads is 31.5%.

Thus, by chance alone, if one were to examine changes in heart attack prevalence in 17 states, one would find that heart attacks decreased in 10 of those 17 states 31.5% of the time (if there were actually no true change in heart attacks). This is far beyond any reasonable level of statistical significance (which is usually set at about 5%).

If one is going to exclude any study because of methodological weaknesses, it would have to be the Lippert and Gustat study.

My impression remains that ANR is not objectively analyzing the methodology of these studies and excluding those whose methods are not scientifically solid. Instead, ANR is finding reasons to exclude the unfavorable studies while not applying the same standards to studies with favorable results.

The rest of the story is that this adds to the evidence that ANR's omission of all studies with unfavorable findings is an intentional action on the part of ANR to deceive the public about the scientific evidence by hiding negative studies and only sharing studies that support the organization's pre-determined conclusions.

News Article Invokes Smoking Ban as Major Cause of 49% Decline in Heart Attack Admissions in North Cumbria; Junk Science on this Issue Running Rampant

Junk science on the issue of smoking bans and dramatic, immediate reductions in heart attacks continues to run rampant. The latest example is an article in the News & Star (Cumbria, England) which reports that the national smoking ban in England is a major cause of an observed 49% reduction in heart attacks in north Cumbria during a three-month period from October through December, 2007, compared to the same three-month period one year earlier (prior to the smoking ban).

According to the article: "The number of patients suffering heart attacks in north Cumbria has almost halved since the introduction of the smoking ban a year ago. ... According to the Department of Health, there was a 49 per cent reduction in admissions across north Cumbria over a three-month period. This compares to a national drop of two per cent, with the total admissions falling from 4,979 to 4,889. Experts claim that one of the reasons for this drop has been the ban on smoking in public places, which has encouraged more people to give up. The latest figures look at the three-month period from October to December 2006, compared to the same period a year later – after the ban. When broken down they show that, in 2006, 33 people were admitted to the Cumberland Infirmary in Carlisle with heart attacks. This compares with 21 in the same period of 2007. Meanwhile 26 patients were admitted to Whitehaven’s West Cumberland Hospital in 2006, compared with ten over same period last year."

The Rest of the Story

There's just one problem with this "research." The smoking ban is being invoked to explain the 49% decline in heart attack admissions in North Cumbria compared to just a 2% decline in England as a whole. The problem? The control group in this case - England - is not a control group but is, in fact, the intervention group. In other words, the smoking ban was implemented in all of England, so a 49% decline in heart attacks in North Cumbria in light of a much smaller 2% decline in the rest of the country cannot be attributed to the smoking ban.

If anything, these data suggest that the conclusions from Helena, Pueblo, and Bowling Green are wrong and that smoking bans do not produce the kind of dramatic declines in heart attacks that anti-smoking researchers have claimed. After all, a 2% decline in heart attacks is small enough that one cannot be sure any substantial reduction in heart attacks occurred as a result of the smoking ban. But certainly, there was no 40% decline, as claimed in Helena, or a 27% decline, as claimed in Pueblo, or anything close to the 19% decline claimed in a meta-analysis of all the published studies.

Perhaps more alarming than the fact that the conclusions from these data are completely unsupported is the apparent bias in the way these data are being analyzed. One cannot simply compare the number of heart attacks during a chosen period before and after the smoking ban and attribute any change to the smoking ban. Using that same reasoning, one would be forced to conclude that the smoking ban in England had no effect on heart attacks, because in 42% of England's hospital trusts, there was no change (or an increase in heart attacks) during the first year after implementation of the smoking ban.

In fact, the finding that heart attacks declined in 58% of the hospital trusts is not significantly different from the expectation that heart attacks would decline in 50% of the trusts under the assumption that the smoking ban had no effect on heart attacks. If one is really going to employ the reasoning being used in the above analysis, then one would have to conclude that there is no evidence to support the conclusion that the smoking ban had any effect on heart attack admissions.

What I don't really understand are two things:

1. Who is it who is putting out all of this junk science, and why are they doing it? It seems hard to believe that newspaper reporters themselves have some sort of agenda to show that the smoking ban is causing massive declines in heart attacks. It seems more likely that the health department or some other entity is publicizing these data and misleading reporters into believing that the data support such a conclusion.

2. Why is it that these data are not being reported as refuting the conclusions from Helena et al. that there is a dramatic reduction in heart attacks caused immediately by implementation of smoking bans? Whether the decline in heart attacks was only 3% as previously reported or 2% as reported here, these data do not support the conclusion that smoking bans lead to substantial, immediate declines in heart attacks.

What does seem clear is that the studies of the Helena ilk have somehow opened the door for junk science as an acceptable tactic in tobacco control research.

And here is the most amazing thing: very few people or organizations within tobacco control are speaking out against the deterioration of the science.

I think these data from England actually explain why the Helena et al. studies are so flawed. If you just pick several specific locations to study, you are bound to find some locations that experience major declines in heart attacks. Within England, sure enough - Cumbria experienced dramatic reductions in heart attacks. Most of the 49% decline was probably just due to random variation given the low numbers involved.

What you need to do is a systematic study where you look at many locations affected by a smoking ban - preferably examining many countries or many states with such bans and comparable control locations without such bans. When one does this in England, it becomes immediately apparent that the finding in Cumbria was just a fluke. There is no consistent finding of a 49% decline in heart attacks across England. This is called random variation or chance.

Most likely, locations chosen for study are those in which investigators notice that there seems to be a decline in heart attacks. If heart attacks went up after a smoking ban, most likely investigators in those locations would not opt to conduct and publish such a study.

Interestingly, this serious problem of publication bias is not even mentioned in the meta-analysis of these studies which was recently published online in Preventive Medicine.

To really answer this research question, what is needed is a systematic study of multiple locations with smoking bans. I believe that McFadden and Kuneman have conducted such a study, in which they examined heart attack trends in a number of U.S. states with and without smoking bans for which data were available. This study has not yet been published, as not surprisingly, it is probably getting unfair reviews from anti-smoking researchers.

I conducted my own analysis of the data, using McFadden and Kuneman's methods, for all U.S. states with and without smoking bans for which data were available. I found no evidence that there is any substantial, immediate decline in heart attack admissions in states with smoking bans.

It doesn't make sense to me that anti-smoking researchers and groups aren't willing to criticize the conclusions of these studies and to decry the junk science that is being used. After all, deterioration of the science being used in tobacco control is not an asset; it is a severe liability.

However, as I am learning, science in tobacco control is judged not by its quality, but by the direction of the results.


(Thanks to Michael J. McFadden for the tip).

Wales Report Claims that Smoking Ban Reduced Heart Attacks But Fails to Present Data, Which Show an Increase in the Expected Number of Heart Attacks

The annual report of the Chief Medical Officer for Wales for 2008 was released yesterday and as anticipated, it concluded that the smoking ban in Wales resulted in a decline in heart attack admissions. The conclusion was widely disseminated.

According to an article published by BBC News, entitled "Heart Attacks Fall After Smoking Ban, Report Says": "The number of people suffering heart attacks has reduced since the smoking ban in Wales began, a report by the chief medical officer has found. ... Dr Jewell's annual report Preventing the Preventable pointed to statistics which showed the number of hospital admissions for heart attacks in 2007/2008 had fallen by 3.7% on the previous year, down from 4,324 to 4,164."

According to another article in the Daily Post, entitled "Smoking Ban Sees Fall in Heart Attacks in Wales," the smoking ban in Wales has resulted in a steep decline in heart attacks. The announcement of this finding was heralded by ASH Wales, which stated: "Bans on smoking in enclosed public places have been demonstrated to effectively reduce heart attack rates so it is not surprising to see Wales following this positive trend."

According to the article: "New figures this week are expected to reveal how the first full year of the public smoking ban in Wales heralded a steep decline in heart attacks. The findings will be contained in the Chief Medical Officer for Wales’ annual report showing hospital admissions have fallen since the ban came into force."

The specific findings highlighted in the article are as follows: "There was a 12.5% fall in the number of patients admitted to hospital with a heart attack between October and December last year, compared to the same period in 2006, before the ban on smoking in enclosed public spaces was introduced in Wales: some NHS trusts have seen the number of heart attacks fall by up to 40% in the same period."

The annual report briefly addressed the issue of the Wales smoking ban's effect on heart attacks, stating as follows:

"Although we are not likely to see the full health benefits of the legislation for some time, for instance an anticipated reduction in lung cancer, there is already some evidence that the ban is having a beneficial effect on health. Hospital admissions for heart attacks were reduced in 2008 and although this decline cannot be wholly attributed to the smoking ban, some studies suggest that at least some of the reduction is due to the legislation."

No other data were presented in the report regarding the relationship between the smoking ban and the trend in heart attacks.

The Rest of the Story

It is unfortunate that the annual report concluded that the smoking ban resulted in a decline in heart attacks in Wales but failed to present any data to back up that conclusion. Even allowing the benefit of the doubt and accepting that there was a 3.7% decline in heart attacks in Wales from 2005/2007 to 2007/2008, this pretty much means that there was no effect of the smoking ban on heart attacks, since the number of heart attack admissions was dropping by between 5% and 10% annually prior to the implementation of the smoking ban.

By failing to mention the baseline trend of declining heart attack admissions in Wales, the article (and the public officials and health groups contributing towards this distortion of the science) gives a misleading impression. Rather than causing an acceleration in the pre-existing rate of decline in heart attacks, it appears that the smoking ban was associated with a leveling off of that decline.

Of course I'm not arguing that the smoking ban increased the number of heart attacks. But it is difficult to see the basis for any credible conclusion that the smoking ban had any effect whatsoever on heart attacks. Clearly, the conclusion of the report is not justified on the basis of the scientific facts.

Fortunately, thanks to Christopher Snowdon over at Velvet Glove Iron Fist, we know that annual data on emergency room heart attack admissions are available from Health Solutions Wales. These data present the annual number of heart attack admissions for all of Wales, with the year-long periods starting in April of one year and going through March of the following year. This is convenient, since the Wales smoking ban went into effect in April 2007. Thus, any effect of the ban on heart attacks would be expected to show up in the 2007/2008 and 2008/2009 data points.

I created a graph of the trends in emergency room heart attack admissions in Wales from 2003/2004 through 2008/2009. The arrow shows the point at which the smoking ban went into effect.



The graph clearly shows that contrary to the conclusions of the report, as well as the conclusions of ASH Wales, the smoking ban was not associated with any decline in heart attacks. In fact, the data demonstrate that the smoking ban was associated with a leveling off of the trend of declining heart attacks in Wales.

In other words, in the two years since the Wales smoking ban has been in effect, there have been more heart attacks than would have been expected based on the pre-existing trends in heart attacks in the country.

This doesn't mean that the smoking ban increased the number of heart attacks, but it does refute the conclusions of the Institute of Medicine and many anti-smoking groups that smoking bans result in an immediate and dramatic reduction in heart attacks.

Although the Institute of Medicine committee was made aware of the data from Wales, it chose to ignore these data. In essence, the committee cherry-picked the data which supported its conclusion and ignored the data which refuted it. Unfortunately, the data which the committee ignored were the more reliable data, because they were based on large populations. The few studies that drove the committee's findings were conducted in small communities with small numbers of acute coronary events and huge year-to-year variations in heart attacks.

These data from Wales are quite convincing and demonstrate that on a national level, the smoking ban was not associated with any decline in heart attacks. I once again challenge anti-smoking groups to disseminate these findings, and I again offer a $100 prize to any group that previously disseminated the conclusion that smoking bans immediately reduce heart attacks and which now publicizes these findings which refute that conclusion. Of course, I realize that these anti-smoking groups are not interested in the truth; they are only interested in conclusions that are favorable to their position. Thus, I feel confident that I need not worry about losing the hundred bucks.

Christopher Snowdon has conducted a similar analysis to mine and has reached the same conclusion: the Wales smoking ban clearly did not result in any decline in heart attacks. Snowdon's graphs also demonstrate that if anything, the smoking ban resulted in a leveling off of the previous trend of rapidly declining heart attacks in Wales. You can read Christopher Snowdon's comprehensive discussion of the Wales data at these sites: Post 1; Post 2.

The rest of the story is that contrary to the conclusions being disseminated by the media due to misleading data and distorted science by anti-smoking health officials and anti-smoking advocacy groups, the smoking ban in Wales clearly failed to result in a decline in heart attacks during its first two years. While the Chief Medical Officer is absolutely correct that eventually the cardiovascular benefits of the smoking ban will be seen, it is simply too early to expect to see a decline in heart disease due to a reduction in secondhand smoke exposure.

The reliance upon shoddy science regarding the short-term effects of smoking bans on heart attacks has become a rapidly deteriorating aspect of the scientific integrity of the tobacco control movement. Despite repeated pleas and warnings to restore more rigorous scientific standards, which I have been issuing for the past three years, the movement has failed to respond. As a result, data such as that being released today clearly refutes the conclusions that the anti-smoking groups have disseminated.

They jumped the gun, and it turns out that they were wrong. That they were wrong because of a strong bias is regrettable. That they fail to correct themselves in light of clear evidence of the invalidity of their conclusions is worrisome. That they don't appear to even care whether they are distorting the science and misleading the public is inexcusable.

Study of Trends in State Heart Attack Admissions Refutes Conclusions of Helena et al. Studies

A study of trends in annual heart attack admissions through the emergency room by state refutes the conclusions of the Helena, Pueblo, Piedmont, and Bowling Green studies which concluded that smoking bans cause immediate, drastic declines in heart attacks. The study was conducted by Michael J. McFadden and David W. Kuneman. A preliminary version of the study appeared online in November 2005, while the final version, discussed on the American Council on Science and Health (ACSH) FactsAndFears blog, confirmed and strengthened the original findings.

McFadden and Kuneman overcame the two chief limitations of the existing research: (1) the small number of heart attacks in the cities studied, which resulted in tremendous baseline year-to-year variability in heart attack rates; and (2) the bias inherent in relying only upon the experiences of only a few small cities in making generalizations intended to apply to larger populations. They accomplished this by considering the following premise: if smoking bans cause an immediate decrease in heart attack admissions on the order of a 25% to 50% decline, then if one examines trends in heart attack admissions on an entire state level, then one should certainly observe a notable decline immediately following the implementation of statewide smoking bans.

Using data on emergency room admissions for acute myocardial infarction (heart attacks) from the Agency for Healthcare Research and Quality's HCUP database, McFadden and Kuneman examined trends in four states that implemented statewide bar and/or restaurant smoking bans - California, Oregon, Florida, and New York - and five states with neither a statewide smoking ban nor widespread local smoking bans - Arizona, New Jersey, South Carolina, and Iowa. They also examined trends in heart attack admissions for the United States as a whole.

California's restaurant smoking ban took effect in January 1995. In that year, heart attack admissions in California increased by 0.6%. In 1996, admissions increased by 2.9%. The corresponding changes for the United States were an increase of 3.2% in 1995 and 3.9% in 1996. California's bar smoking ban took effect in January 1998. In that year, heart attack admissions in California increased by 6.0%, compared to an increase of 6.2% in the nation as a whole. In 1999, admissions increased by 3.7% in California and decreased by 1.3% in the U.S.

Florida banned smoking in all restaurants in July 2003. Its heart attack admissions decreased by only 0.7% that year, and by only 2.0% the following year. In comparison, admissions in the U.S. decreased by 2.8% in 2003 and 8.2% in 2004.

Trends in heart attack admissions following the Oregon and New York smoking bans were also not found to be substantially different from national trends, or from trends in the comparison states without smoking bans.

The Rest of the Story

While this study certainly does not prove that smoking bans have no effect on heart attack admissions, what it does is demonstrate that when one examines population-based data for an entire state, one does not find any evidence of a dramatic decline in heart attacks immediately following the implementation of smoking bans. This casts serious doubt on the conclusion of the Helena, Pueblo, Piedmont, and Bowling Green studies. If smoking bans truly cause an immediate and dramatic decline in heart attacks, on the order of a 25% to 50% reduction, then why do we not observe any evident decline in heart attacks when entire states implement smoking bans.

The chief limitation of the study is that some localities within these states had already enacted smoking bans, so one would not expect to see as dramatic an effect on a statewide level. However, the proportion of residents in these states covered by local smoking bans was not particularly high. For example, the authors cite data that only 14% of Californians were covered by a smoke-free restaurant law in 1993. This increased to 100% in 1995. Yet the number of heart attack admissions increased from 1993 to 1995 (and increased further in 1996). The corresponding changes in the U.S. data were similar. So it does not seem that the existence of some local smoking bans is enough to invalidate the study conclusion.

I have already discussed in detail the reasons why I believe the conclusions of the Helena et al. studies are unjustified. Briefly, the chief flaw of these studies is that they are unable to rule out the very likely possibility that the observed changes in heart disease admissions in these cities during the study period are due primarily to random variation, rather than to the smoking bans. There is tremendous natural (random) variation in the heart disease admission rates in these cities because of the small population sizes. Because we are dealing with such small numbers of admissions, the percentage change in admissions from one year to the next is very high, even without any smoking ban.

While these papers make some attempt to account for these baseline trends, I do not believe that they go back far enough in time to do so adequately.

Because McFadden and Kuneman have examined heart attack trends among large populations, the number of heart attacks is much higher, and therefore the degree of underlying variability in the annual number of heart attacks is much lower. It is therefore easier to identify any major changes in the underlying trends.

I think it is high time that my fellow tobacco control researchers and practitioners recognize that the Helena et al. studies are examples of shoddy science that apparently now passes as acceptable in tobacco control research. While I support workplace smoking bans, I do not believe that we should be using shoddy science to promote them.

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?