Thursday, October 15, 2009

Herald-Leader's lazy reporting passes on junk science on second-hand smoke

Well, the health nannies are at it again. Reporter Mary Meehan at the Lexington Herald-Leader helps pass on junk science on the issue of smoking bans in today's story on a new report from the University of California, San Francisco's Institute of Medicine:
A major report confirms what health officials long have believed: Bans on smoking in restaurants, bars and other gathering spots — like the ones enacted in several Kentucky cities, including Lexington — reduce the risk of heart attacks among non-smokers.
All of this, of course, in the service of the cause of smoking bans. If second-hand smoking has no measurable health effects, then the argument for smoking bans goes down the tubes. Reports like this new one land on a journalist's desk, the editor tells you to do a story, and you pass on the information without any critical analysis whatsoever.

Notice that Meehan--and the primary AP writer Lauran Nygaard--offer no comment whatsoever from opponents of smoking bans to the study. When I was a journalist, we actually quoted both sides to the issue.

Then there is the problem that the press release from a report from which lazy journalists get their information don't necessarily reflect what's actually in the report, which appears to be the problem in the present case.

Here is a portion of the "Report Brief" from the Institute of Medicine on the studies that were used in this report:
The committee was unable to determine the magnitude of the effect because of the variability among and uncertainties within the 11 studies analyzed in this report. The distinctive characteristics of smoking bans cause them to vary greatly. For example, these studies varied by the type of venue covered by the bans (such as offices, other workplaces, restaurants, and bars) and compliance with and enforcement of the bans. Other differences included the length of follow-up after implementation, population characteristics (such as underlying rates of heart attacks and prevalence of other risk factors for heart attacks), size, secondhand-smoke exposure levels before and after implementation, preexisting smoking bans or restrictions, smoking rates, and method of statistical analysis.
Ahem. It couldn't determine how much smoking bans affected the incidence of heart disease, but it was sure that it did affect it.

Maybe the Institute for Health could have taken into account the fact that heart disease has gone down everywhere in this country since the late 90s. Here is the UPI on what has happened with heart disease in recent years:
The number of patients admitted to hospitals for treatment of coronary heart disease declined 31 percent from 1997-2007, U.S. health officials said.

A report by the Agency for Healthcare Research and Quality, part of the U.S. Department of Health and Human Services in Rockville, Md., also said that as a result of the decline, coronary heart disease no longer ranks as the leading disease treated in hospitals but ranks No. 3. Heart failure was ranked at No. 2 and pneumonia is the most common disease treated in hospitals, the report said.

Hospitalizations for heart attack declined by 15 percent, from 732,000-625,000, during the study period. Hospitalizations for stroke fell 14 percent, from 616,000-527,000 and a drop in rank from No. 6 to No. 15.
So exactly how does the report distinguish between the general decline in heart disease and the decline caused by smoking bans? Where is the control for these studies? How do we know that the reduction wasn't due to the general decline in smoking among the population rather than on the increase in cities with smoking bans? Or better treatment of heart disease?

I haven't read the whole report: $38.70 is a little steep for an online report these days. But Michael Siegel, a physician at the Boston University School of Public Health has. Here's his take:
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.
This is, in fact, a classic example of the post hoc ergo propter hoc fallacy: that because one thing follows another, the second thing is therefore the effect of the first. Not even an attempt to discriminate between the possible causes.

Of course, you won't find this in the Herald-Leader's story. I mean after all, it would take all of five minutes to hunt down on the Internet.


Anonymous said...


I was browsing through the collection of the National Academies Press, for the publications cited in Levitt/Dubner's embarrassingly wrong "SuperFreakonomics" (currently DOA), when I came across an excellent title on environmental tobacco smoke here

Unfortunately it doesn't offer any quick quotes and it is a hard slog - as serious scientific titles are. You could do worse than spend some time acquainting yourself with the findings on this topic. As it happens with every scientific topic the contrarian (or common sense advocate) takes on the established theory with as much preparation as Don Quixote. Read the title and you will learn why.


Kycobb said...


There are absolutely known harmful health effects of second-hand smoke for asthmatics and persons allergic to cigarette smoke. That provides more than sufficient grounds to ban smoking in indoor public places. In a generation, noone will even remember this was an issue-you don't feel you are less free because there aren't spittoons conveniently located everywhere to spit tobacco juice in, do you?