Two more heart attack studies

As an addendum to the previous post, I should mention two more recent studies of smoking bans and heart attack rates. The first, from Brad Rodu, Nicholas Peiper and Philip Cole, published a couple months ago in Journal of Community Health, examines rates in six states and finds no effect:

The AMI mortality rate among persons age 45 + years (deaths per 100,000 persons, age-standardized to the 2000 US population) in the 3 years before adoption of the smoke-free ordinance (the expected rate) was compared with the rate observed in the first full year after the ban (the target year) in six US states. Target-year declines were also compared to those in states without smoking bans. Target-year declines in AMI mortality in California (2.0%), Utah (7.7%) and Delaware (8.1%) were not significantly different from the expected declines (P = 0.16, 0.43 and 0.89, respectively). In South Dakota AMI mortality increased 8.9% in the target year (P = 0.007). Both a 9% decline in Florida and a 12% decline in New York in the 2004 target year exceeded the expected declines (P = 0.04 and P < 0.0002, respectively) but were not significantly different (P = 0.55 and 0.08, respectively) from the 9.8% decline that year in the 44 states without bans. Smoke-free ordinances provide a healthy indoor environment, but their implementation in six states had little or no immediate measurable effect on AMI mortality.

The second unpublished study [pdf] looks at rates in 74 US cities that implemented smoking bans. It finds a decline of a mere 3% following implementation. Contrary to expectation, the effect disappears entirely when restricted to the 43 cities whose bans were meaningful. All things considered, it lends support to the idea that smoking bans have no short-term impact on heart attack rates.

[Thanks to Chris Snowdon and Michael McFadden for the links.]

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Two years later, no heart miracle in Oregon

I have an op/ed up today at The Oregonian addressing the question, “Whatever happened to Oregon’s heart miracle?” Oregon’s statewide smoking ban took effect in 2009 and was predicted by many advocates to result in a steep decline in the rate of heart attacks of 17% or more. I contacted the Oregon Public Health Division to see if hospital data bore this out. Unsurprisingly, it didn’t.

For those who are curious, here is the age-adjusted rate of heart attack admissions for Oregon as provided to me by the state, with percentage change from the previous year in parenthesis:

2003 198.4
2004 181.2 (8.67)
2005 166.8 (7.95)
2006 166.6 (0.12)
2007 163.4 (1.92)
2008 152.5 (6.67)
2009 141.5 (7.21)
2010 137.1 (3.11)

And here is the same data in graph form:

oregonami

As I explain in the op/ed, the drop in 2009 is on trend with those in previous years and can’t be reasonably attributed to the smoking ban, and even under the rosiest interpretation it is still less than half of what ban advocates predicted.

The task of explaining this discrepancy fell to Ty Gluckman, director of clinical excellence for Providence Heart and Vascular Institute. It was Gluckman who wrote in 2009 that “[…] it’s highly likely that Oregon’s heart attack rates are already dropping as we near the law’s one-year anniversary. If we reduce the number of acute heart attacks by 17 percent, there will be at least 1,100 fewer hospital admissions in Oregon in just one year.” I said at the time that there was no way this was going to happen. You can read his entire response here.

Undaunted by contrary data, Gluckman suggests that Oregon’s less than stunning decline in heart attacks is due to two factors. One is that many bars were already banning smoking voluntarily before the ban. Another is that over this same period Oregonians were becoming more obese. However these confounding factors hold to some extent just about everywhere, which is why the only way to test the impact of bans is by 1) looking for increased rates of decline after implementation and 2) comparing these results with control populations that were not under a ban. This is essentially the method of the RAND study cited in my article, which found no impact.

The story in Oregon is consistent with that of other large populations that experienced no noticeable decline in heart attack rates following implementation of a smoking ban. See for example this New Zealand study, omitted from the meta-analysis Gluckman cites, or the publicly available data from many national governments.

Today’s article is my third Oregonian contribution on the subject of the state smoking ban. In 2008 I argued that the ban wasn’t actually about saving lives. In 2009 I argued that the its exemptions were unduly restrictive. Finally, also in 2009, I wrote for Doublethink about the last night of legal smoking at my favorite cigar hangout, the legendary Horse Brass pub.

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We’ll always have Helena

In 2004, physicians Richard Sargent and Robert Shepard published a study making the astounding claim that a six-month ban on indoor smoking in the town of Helena, Montana resulted in an immediate 40% drop in the city’s rate of heart attacks. Ever since then it’s become sport among anti-smoking researchers to search for similar “heart miracles” in other places that have implemented smoking bans. Curiously, the miracles tend to get smaller as the populations get larger. Big effects were found in Bowling Green, Ohio and Pueblo, Colorado, but they never carried over to state or national levels. A recent examination of England’s heart attack rates could claim at best a 2.4% reduction, and that with dubious manipulation of the data.

This has led many critics to allege that the heart miracles of Helena and elsewhere are statistical flukes that emerge from small sample sizes. There is new evidence to support this view: A comprehensive study led by the RAND Corporation used data from throughout the United States to see if there is a relationship between smoking bans and rates of heart attacks. It found no statistically significant effect. Further, it found that rates in populations comparable to those cited in previous studies are highly volatile and on average cancel each other out. This suggests that the many studies claiming large effects are the result of publication bias, not actual declines caused by smoking bans.

Tobacco researcher Michael Siegel, himself a supporter of smoking bans, sums up the significance of the study:

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.

The case for comprehensive smoking bans leading to immediate reductions in heart attacks has never been strong and now there is substantial evidence against it. Jurisdictions that have not yet imposed smoking bans have one fewer reason to do so; those that have should restore business owners’ rights to set their own policies, as the Dutch have recently done.

I would like to think that the anti-smoking movement and press would acknowledge these findings, but I’m not optimistic. As of now a Google News search for “smoking ban RAND Corporation” yields only one result, in contrast to the dozens or more that usually follow reports of sudden declines.

Previously:
An Oregon heart miracle?

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What really happened in Starkville, revisited

About a year ago I criticized a “study” from Mississippi State University alleging that implementation of a smoking ban in Starkville, MS caused a dramatic decline in heart attacks. The problem was that the study was in fact just a press release and the data from control groups hadn’t even been collected yet. Without control groups there was no justification for asserting that the decline in heart attacks was caused by the smoking ban rather than other factors. I challenged the authors, Dr. Robert McMillen and Dr. Robert Collins, on this point and they declined to respond, saying only that they would continue their research when more data arrived.

Now the data is in and they have released another study confirming their hypothesis. To their credit they have control groups this time. What they don’t have are tests of statistical significance. I’ll hand it over to Michael Siegel:

This study violates the most fundamental principal of epidemiology and biostatistics: you must evaluate any scientific hypothesis to see whether the results could be explained by chance. In other words, you must determine whether your results are statistically significant.

A persistent flaw in studies of this type is reliance on small population sizes to extrapolate an exaggerated effect. This one appears no different. Siegel again:

I did my own calculations based on the results reported in the study and based on a conservative estimate which maximizes the likelihood of finding a statistically significant difference, I found that the difference between the two rates of decline was not even close to being statistically significant. […]

For these findings, which are exquisitely sensitive to a simple shift in one heart attack here and one heart attack there, one must not put any confidence in their statistical meaning. Clearly, the role that these are just chance differences cannot be ruled out given the small sample size. Nevertheless, the study goes as far as telling us the exact cost savings from the heart attacks averted due to the smoking ban.

McMillen and Collins are getting closer to doing real science. Close, but still no cigar!

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A heart non-miracle

Just when I thought I was out they pull me back in! Though living in Portland I can’t completely resist the lure of DC, so I’ve joined the blogging team at the Washington Examiner. It’s good to get back to the policy writing I’ve been neglecting lately and publishing there it will reach a larger audience. I’ll link to most of the things I write for the Examiner on this blog too. If you’d like to subscribe to all Opinion Zone blog posts the RSS feed is here.

My first post takes a look at how anti-smoking researchers spin this chart into proof that England’s smoking ban saves lives:

ami-england

The best they can come up with is to dubiously attribute a 2.4% decline in heart attacks to the smoking ban in the first year of its implementation. This is in stark contrast to the wild claims of 40, 27, and 18 percent in previous studies, which have been decisively revealed as junk science.

In the wake of this statistical drubbing you might think anti-smoking activists would learn not to attribute too much to secondhand smoke. Well, you would be wrong:

A new study published online ahead of print in the Archives of General Psychiatry concludes that secondhand smoke exposure is a cause of mental illness, including depression, psychoactive substance use, schizophrenia, delirium, and mental and behavioral disorder (see: Hamer M, Stamatakis E, Batty GD. Objectively assessed secondhand smoke exposure and mental health in adults.

Here we go again!

[Image courtesy of the always interesting Christopher Snowdon.]

Previously:
What really happened in Starkville?
An Oregon heart miracle?
Lazy reporting and the Pueblo ban study

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About that meta-analysis…

A few months ago newspapers eagerly picked up news of a meta-analysis of smoking ban studies finding that bans were associated with a 17% decline in heart attack rates in their first year. Will any of them report this whopper of a correction?

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.

That’s from Michael Siegel, of course, one of the few anti-smoking researchers defending scientific accuracy.

The shoddiness of the science behind the claims of rapid drops in AMI rates following smoking bans never ceases to amaze, nor does journalists’ willingness to report on it uncritically.

For more on the extremely flawed Pueblo study, see here.

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A warning about Wales

The Daily Post reports that new figures soon to be released by Wales’ Chief Medical Officer will show that heart rates have dropped in the region during the second year of its smoking ban. I look forward to seeing those figures, but the close of the article is particularly striking:

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.

See anything suspicious there? To my knowledge there isn’t anyone promoting the theory that smoking bans only reduce heart attacks in the final three months of the year. So why focus on just that time period?

The answer is that cherry-picking those 3 months supports ban proponents’ predetermined conclusion. As Christopher Snowdon has shown with the government’s own data, the rate of AMI actually rose slightly during the year the ban took effect and there were more heart attacks in the 5 months immediately following the ban than there were in those same months the year before. Overall there was practically no difference in the AMI rate between the two years, which is surprising since Wales’ rate of heart attacks had been on a downward trend. A fair reading of all the data is that the ban had no discernible effect, yet the story told by activists and mindlessly repeated by reporters is that the ban caused a reduction in heart attacks.

Such a weird statistic should have immediately raised flags for a journalist. A quick search on Google for the words “Wales,” “smoking ban,” and “heart attacks” would have revealed why the figure was selected. Unfortunately Post reporter Tom Bodden took it at face value, so readers don’t get the full story and the misleading statistic is propagated even more widely.

As Snowdon notes, the Welsh rate of AMI has been falling in recent years by as much as 10% per year. The fact that it didn’t fall in the year smoking was banned is an anomaly. My guess is that in the report about to be issued the rate will have resumed its previous decline and, in a classic case of conflating correlation with causation, researchers will credit the drop solely to the smoking ban.

It will be up the to journalists covering the report to treat it with skepticism, ask tough questions, and at the very least seek out a critical source before phoning in their stories. I’m not optimistic that they will.

Update 12/7/09: My prediction seems to be too optimistic. Chris decided to check the data again today and it turns out that the heart attack rate in Wales actually increased last year. So how will the upcoming report show that it declined? Well, that will be interesting to find out!

Update 12/9/09: Here’s the story and here’s Snowdon on why it’s just another example of junk science.

Previously:
More lazy tobacco reporting

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Indy smoking ban increases heart attacks

In Indianapolis, the smoking ban enacted in 2006 has unexpectedly caused an increase in heart attack deaths:

The ban, which affected all workplaces, including restaurants but excluding bars, went into effect on March 1, 2006. Had the smoking ban resulted in an immediate decline in heart attacks, as claimed by a number of anti-smoking groups and researchers and by a special Institute of Medicine committee, one would have expected the heart disease death rate in Marion County to have decreased in 2006, compared to 2005.

Data from the Marion County Health Department, however, show that the age-adjusted heart disease death rate for Marion County actually increased by 16% from 2005 to 2006, going from 171.0 to 197.6 deaths per 100,000 population.

This reversed a trend of declining heart disease death rates prior to the smoking ban. The rate had declined by 4.4% from 2002 to 2003, by 6.0% from 2003 to 2004, and by 5.8% from 2004 to 2005. Thus, the increase of 16% observed from 2005 to 2006 was a striking increase that coincided precisely with the implementation of the workplace and restaurant smoking ban.

Of course the ban didn’t actually cause the increase any more than bans in other cities caused the decreases so often hyped by anti-smoking advocates. And if the death rate can fluctuate this much in Indianapolis, a city of nearly 800,000, then the odds of getting meaningful data out of towns like Starkville, MS, Pueblo, CO, and Helena, MT are pretty damn low.* The fact that ban advocates cling so tightly to those success stories is an indication of just how the weak the association between bans and decreases in AMI really is.

*Those studies used overall rates of AMI rather than the rate of AMI deaths, but the two rates should move in tandem.

Previously:
What really happened in Starkville?
Lazy reporting and the Pueblo ban study

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What really happened in Starkville?

Last week I briefly commented on a study of heart attack (AMI) rates in Starkville, MS that found a 27% reduction in the AMI rate in the three years following the imposition of a smoking ban. Though I was initially dismissive, I decided to email the authors, Dr. Robert McMillen and Dr. Robert Collins, to ask for a copy of the study and to see the data. I expected to find the usual flaws, but what I found was even worse: In truth there is no completed study, the relevant data haven’t even been collected yet, and there are no grounds for concluding that the decline in heart attacks had anything to do with Starkville’s smoking ban.

Journalists covering the story reported that the results came from a study that had just been released. This is understandable, since that is what Mississippi State’s* press release claims:

A Mississippi State study released Monday [Nov. 9] shows a 27 percent decrease in heart attacks among Starkville residents since the city passed a smoking ban in 2006.

The “study” was actually just a two page preliminary report [PDF] that has not been published in a journal or subject to peer review. Nonetheless, in the press release and the report the authors express certainty that the decline is attributable to the smoking ban:

Without spending a dime, the community of Starkville has decreased heart attacks by more than 25% […]

Current research shows that smoking bans in Starkville have contributed to a 27% reduction in the heart attacks of local residents […]

There are two flaws that plague studies of heart attack reductions in small cities like Starkville. One is the size of the population, which makes wild fluctuations in the data possible. Starkville’s resident population is just a little over 20,000, so there’s nothing to be done about that. The other flaw is the lack of control groups. AMI rates could be declining for reasons unrelated to smoking bans, so it’s necessary to compare communities with smoking bans to similar communities without them.

Admirably, McMillen and Collins intend to collect data from other Mississippi cities to act as control groups. However they don’t have this data yet. When I wrote to them asking for a copy of the study, all I got was this email from Dr. McMillen:

The results that we released in our 2 page report are preliminary results form a larger study. The study examine AMI admissions from several communities that have passed smoke-free ordinances, as well as communities that have not. The latter will serve as controls for the purpose of comparison. The hospital in Starkville was the first to provide us with AMI admission data. When we have received data from the other communities in our study we will prepare a manuscript that compares AMI admissions before and after the smoke-free laws were enacted in communities with and without smoke-free laws.

Without the data from control groups there is no evidence that the decline was caused by the smoking ban. There’s absolutely no way to know whether the ban deserves complete, partial, or zero credit for the decline, and any statement to the contrary is pure speculation.

Michael Siegel has looked into Mississippi’s heart attack data and found that the AMI mortality rate has been trending downward throughout the state:

[…] from 2000-2002 to 2003-2005, there was a 19.3% decline in heart attack deaths in Mississippi. And from the period 2000-2002 to 2006-2008, there was a 29.2% decline in heart attack deaths in Mississippi.

From 2003 to 2008, heart attack deaths in Mississippi fell by 19.1%. From 2002 to 2008, they fell by 29.4%. And from 2000 to 2008, they fell by more than one-third: by 33.9%.

This demonstrates that heart attacks were declining substantially in the state of Mississippi anyway, even in the absence of a smoking ban. It suggests that if Starkville had not enacted a smoking ban, the study still would have found a very large decline in heart attacks from 2003-2005 to 2006-2008.

On Friday I wrote to McMillen and Collins to ask on what basis they reached their conclusion without having received the data from their control groups:

In the two page report you imply rather strongly that the decline in Starkville’s AMI rate is due to the smoking ban (“Without spending a dime, the community of Starkville has decreased heart attacks by more than 25%…”) (“Current research shows that smoking bans in Starkville have contributed to a 27% reduction in the heart attacks of local residents…”). I am curious to know how you have reached this conclusion without having received the data from control groups, as this seems to go far beyond what one could determine from your preliminary results.

I’ve yet to receive any response from them.

In two of my emails I requested to see the data from Starkville broken down year-by-year. If we are to believe the studies from Pueblo and Helena, the bulk of the decline should have occurred immediately after the ban took effect. It would be useful to know if the same pattern occurred in Starkville. They have yet to release this data.

Collins and McMillen have given their statements a veneer of scientific objectivity without providing the transparency needed to substantiate their claims. This hasn’t stopped them from using their results to push for a statewide smoking ban:

Data from the Mississippi State Department of Health and national figures indicates the state would save an estimated $125 million annually in health care expenses if a legislatively mandated smoking ban was enacted, [Collins] added.

“I plead with the Mississippi Legislature to ban smoking in public places,” Collins said. “Our data reflects the findings of every other community that has looked at what happened when smoking is banned in public venues.”

This is yet another example of what Siegel aptly calls “science by press release.” McMillen and Collins have no basis on which to rest their claims, have not published them in any journal, and haven’t even collected all of their data. Yet because they were critical of tobacco a willing press disseminated their conclusions far and wide without asking difficult questions or consulting critics.

When this study is completed it will be interesting to see what if finds. At that time its results could possibly be informative in the debate over a statewide smoking ban. But to go public with results now, before the data is even collected, is a corruption of science for the pursuit of political ends and unfortunately all too typical for today’s anti-smoking movement.

*Corrected.

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A Starkville miracle

Speaking of heart attack miracles, a new one has been discovered to justify a possible statewide smoking ban in Mississippi:

A ban on indoor smoking has paid big dividends for the health of Starkville residents.

In the three years after the ban was enacted in 2006, Starkville had 27 percent fewer heart attacks than in the three years preceding the ban, based on the results of a Mississippi State University Social Science Research Study released Monday.

Of course none of the reporters covering the story bothered to include of a word of skepticism, and dramatic results like this don’t appear in large samples in the UK, Australia, and US states. But hey, Starkville!

More on the problems with small-town heart attack studies here and here.

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An Oregon heart miracle?

Last week the Oregonian ran an op/ed about lottery revenue that turned out to really be primarily about the Oregon smoking ban. I missed it at the time, but it’s worth rebutting now. The piece is by Ty Gluckman, director of the coronary care unit at Providence St. Vincent Heart and Vascular Institute and a board member for the American Heart Association’s Portland chapter. In short, he’s someone who ought to know better than to write this:

In the midst of the messy process of health care reform, it’s refreshing to see one particular health policy, smoke-free workplace laws, having a documented impact. But despite two recent studies clearly linking the laws to a decrease in heart attacks, the laws continue to be a scapegoat for declines in video lottery sales — with no evidence of this link.

In the first study, published in Circulation: Journal of the American Heart Association, researchers James Lightwood and Stanton Glantz looked at 10 cities in the U.S., Italy and Scotland that have adopted laws restricting smoking in public areas. Their conclusion was astounding: The rate of hospitalization for acute heart attacks was reduced by 17 percent after one smoke-free year.

Even better, the bans continued to reduce heart attack rates over time, with about a 36 percent drop three years after the laws took effect. These results are consistent with the fact that nonsmokers exposed to second-hand smoke at home or at work have a 25 to 30 percent increased risk of developing heart disease. In fact, Lightwood believes that the new findings suggest that the increased risk may be even higher. […]

The two studies released this month should give comfort to our state legislators that the smoke-free workplace law will help make Oregon a healthier place to live. In fact, according to the studies, it’s highly likely that Oregon’s heart attack rates are already dropping as we near the law’s one-year anniversary.

If we reduce the number of acute heart attacks by 17 percent, there will be at least 1,100 fewer hospital admissions in Oregon in just one year. At a cost of more than $35,500 per admission, the savings will be substantial: $40 million.

Before getting in to what’s wrong with this reasoning it’s worth taking a look at Oregon heart attack rates. These are conveniently listed on the state DHS site for the years 2000-2006:

2000 — 36
2001 — 36
2002 — 37
2003 — 36
2004 — 33
2005 — 32
2006 — 31

There are two things to notice here. One is that, as is the case in many regions, there’s a secular downward trend in the rate of heart attack admissions. It’s dropping for reasons other than the imposition of smoking bans. Secondly, there can be significant fluctuations from year-to-year with no clear cause. From 2003 to 2004 there was a decrease of more than 8%. I’m sure there were several laws that took effect on January 1, 2004, but it would be silly to credit them with the drop in heart attack rates just because they occurred contemporaneously.

It’s also worth looking at the county-by-county break down of heart attack rates. Multnomah County, home to Portland’s large population, is very stable, with rates never going up or down by more than two points each year. Baker County (population 16,000+), the first on the list, varies much more wildly:

2000 — 39
2001 — 53
2002 — 31
2003 — 38
2004 — 23
2005 — 20
2006 — 16

Heart attack rates in Baker County jumped nearly 36% from 2000 to 2001. Just as miraculously, they then dropped more than 40% the next year. Does this mean anything? No, of course not. These are just the kinds of fluctuations you get when you examine a small sample. Yet an unscrupulous researcher could take the years 2001 to 2006 and make it look like a change in policy in 2002 brought about dramatic health results. Clearly, if you want to get an accurate view of the effect of a smoking ban on heart attacks, you’d want to look at studies with large sample sizes. Fortunately this data is easily available and there are dozens of states and countries than have implemented comprehensive smoking bans. (Incidentally, the city of Baker passed a partial smoking ban in February of 2000, just prior to the dramatic rise is heart attacks. For some reason anti-smoking researchers don’t include Baker in their studies.)

In the studies cited by Gluckman, where do the authors look? The first, by Lightwood and Glantz, includes such giant metropolises as Helena, MT and Pueblo, CO. Not only that, but because the authors found two studies each for Pueblo and Piedmont, Italy, they double-counted the same data and treated them as independent observations. (For a critique of one of the Piedmont studies, see here.)

The Helena and Pueblo studies are notorious examples of junk science, akin to taking the wild fluctuations in Baker County as significant findings (see my earlier post on the Pueblo study here). No impartial researcher would give them such weight when there is so much other data from larger samples available.

The second study from the IOM isn’t much better. I won’t get into it here, but suffice to say that it too ignores data that show no dramatic declines in heart attack rates following a smoking ban. See, for example, the United States, New Zealand, Australia, and the United Kingdom.

It’s possible that smoking bans do have some small effect on heart attack rates but it’s clear that the “heart miracles” claimed by Glantz and other researchers are illusions of the data created by small sample sizes. It will be important to keep this in mind as Oregon’s data for 2009 come in. Will there be a drop in heart attack rates, maybe even a drop comparable to that seen statewide in 2004? Will there be a few places the size of Baker County that experience not a mere drop by a full-blown miracle? Both outcomes are possible, but it would be foolish to attribute them solely to the smoking ban.

As Gluckman himself writes, the conclusions in the papers he cites are “astounding.” I’ve come to expect that reporters will take such claims at face value, but I hope for better from professional cardiologists like Dr. Gluckman. Those astounding claims should have aroused some skepticism in him. I’m sure he’s an intelligent man and perhaps he just didn’t look into the studies as thoroughly as he should have. As so often happens, confirmation bias can lead smart people to believe outlandish things.

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Balanced tobacco reporting at NYT

The New York Times’ coverage of the new Institute of Medicine report on smoking bans and heart attacks includes these passages:

Dr. Michael Siegel, professor of community health sciences at Boston University, said that such limitations were significant flaws and that the panel was being “sensationalistic” about the impact of smoking bans.

“Anybody could have told you without any kind of review that smoking bans don’t raise heart attacks,” Dr. Siegel said, but “it could be that they have an exceedingly small effect” and that reductions were “just occurring anyway” because of improvements in treatment of heart disease. […]

Dr. Siegel said that connection was “unequivocal,” but that a significant risk applied only in people who have severe heart disease. “An otherwise healthy person is not going to walk into a bar for 20 minutes and have a heart attack,” he said.

I’ve blasted the paper repeatedly for uncritically passing on unsubstantiated claims of tobacco researchers, so good for reporter Pam Belluck for writing a balanced piece.

Congrats also to Michael Siegel for getting his views included. If you missed his detailed rebuttal to the report, be sure to read it here.

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A smoking ban study you won’t see in the news

Michael Siegel takes note of a new study [pdf] examining the effects of smoking bans on heart attacks. Published by RAND, the CBO, the University of Wisconsin, and Stanford, the study examines much larger data sets than previous research. I can’t access the full paper so I’m going off of Siegel’s summary. (If anyone has it, please send. Update: I have it now, thanks.) Here is what the authors find:

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

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

Siegel puts this study’s methodological superiority into perspective:

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

The authors on how publication bias favors pro-ban results:

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

In January uncritical reporters breathlessly spread the news of a study in the small town of Pueblo, CO, that found a 40% reduction in heart attacks over three years following the imposition of a smoking ban. We can expect equally fervent coverage of this new study debunking that claim, right? Right?

I explained the myriad flaws in the Pueblo study in this post. So simple, even a New York Times reporter could understand it!

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Lazy reporting and the Pueblo ban study

The Centers for Disease Control have issued a new report about the impact of the smoking ban in Pueblo, Colorado. The study has the media breathlessly repeating claims that the ban dramatically saves lives. “A smoking ban caused heart attacks to drop by more than 40 percent in one U.S. city and the decrease lasted three years, federal health experts reported Wednesday,” writes Reuters reporter Maggie Fox, who doesn’t bother quoting any dissenting sources. Mary Engle at the LA Times health blog says uncritically that whatever the mechanism behind the fall in heart attacks, “Pueblo’s smoking ban can take the credit.” Bill Scanlon at the Rocky Mountain News throws science to the wind and extrapolates that Colorado will see a statewide “sharp decline” in heart attacks in 2009 — more than two years after its ban went into effect.

I realize times are tough in newsrooms, but there’s no excuse for such biased, lazy reporting. Journalists should treat the claims of ideologically driven anti-smoking groups with just as much skepticism as they would junk science coming from big tobacco companies.

Since the CDC’s report is going to be cited constantly by smoking ban advocates it’s worth taking a look at its methodology and limitations. Fortunately it’s straightforward enough that any moderately intelligent person can understand it. The following is my layman’s reading of the results, with the caveat that I’m approaching this without formal training. Nonetheless, it’s clear that one shouldn’t take this study’s conclusions at face value. Its use by anti-smoking groups, researchers, and the press to promote smoking bans is a case study in the abuse of science for political ends.
Continue reading “Lazy reporting and the Pueblo ban study”

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