Last year Richard Sargent and Robert Shepard, two physicians who had campaigned for a smoking ban in Helena, Montana, announced that their efforts had paid off more dramatically than anyone could have imagined: The ordinance had led to an astonishing 60 percent drop in heart attacks in the six months after it took effect. By the time their study, co-authored by anti-smoking activist Stanton Glantz, was published in the April 5, 2004, issue of the British Medical Journal, the drop they attributed to the ban had become 40 percent -- not quite as impressive but still remarkable. And still preposterous, even if you accept the anti-smoking movement's claims about secondhand smoke and heart disease.
According to the American Heart Association, secondhand smoke is responsible for about 5 percent of heart disease deaths. Even a smoking ban that completely eliminated exposure to secondhand smoke (which Helena's didn't, since it did not apply to private residences) could not achieve anything like the effect described by Sargent, Shepard, and Glantz, who in any case made no attempt to measure exposure.
Hedging their bets, Sargent et al. noted that a smoking ban not only reduces exposure to secondhand smoke but also encourages smokers to quit or cut back. But even if Helena's ordinance caused every smoker in town to quit (which it assuredly didn't), it still could not be responsible for a 40 percent drop in heart attacks. According to the U.S. Centers for Disease Control and Prevention, smoking accounts for about 20 percent of heart disease deaths. An immediate 40 percent drop in heart attacks across the whole population also implies a much quicker and larger risk reduction than is seen in studies of people who quit smoking.
The study was based on tiny, volatile numbers, averaging seven heart attacks a month before the ban and four afterward. "Due to these small numbers," SUNY cancer epidemiologist Geoffrey Kabat wrote in a letter to the British Medical Journal, "the reported difference could easily be due to chance or to some uncontrolled factor."
If Helena's experience wasn't a fluke, something similar should have happened in other jurisdictions with smoking bans. So far, however, no one in New York, Los Angeles, San Francisco, Boston, Chicago, or Dallas has noticed a 40 percent drop in heart attacks. You'd think it would be hard to miss.