Study Casts Doubt on Claims of Immediate Benefits from Smoking Bans

Published September 16, 2011

Statewide smoking bans have “little or no measurable immediate effect” on the number of persons who die from heart attacks, according to a new report by medical researchers at two universities.

In “Acute Myocardial Infarction Mortality Before and After State-wide Smoking Bans,” researchers Brad Rodu and Nicholas Peiper of University of Louisville and Phillip Cole of Univeristy of Alabama write, “Our results are consistent with a recent analysis finding that smoking bans were not associated with short-term declines in mortality or hospital admissions for myocardial infarction or other diseases.”

They add, “This study’s results are consistent with the fact that even the decline in active smoking has played only a minor role in reducing heart disease. A recent study evaluated the contribution of various factors to the decline in coronary heart disease mortality in the US between 1980 and 2000. It estimated that medical and surgical treatments accounted for half of the decline, while changes in all cardiovascular disease risk factors accounted for half. It also estimated that the decline in smoking prevalence accounted for only about 12% of the total decline in heart disease mortality, but even this percentage is subject to a small downward revision due to the association of smoking cessation with overweight/obesity, another cardiovascular risk factor.”

Testing Benefits Claims

Rodu, Peiper and Cole conducted the study after noting several published reports have claimed smoking bans result in almost immediate reductions in heart attack mortality rates. To test the observations, they compared the acute myocardial infarction mortality rate among persons 45 years old or older (deaths per 100,000 persons, age-standardized to the 2000 US population) in the three years before adoption of the smoke-free ordinance (the expected rate) with the rate observed in the first full year after the ban (the target year) in six U.S. states.

Target-year declines were also compared to those in states without smoking bans.

Target-year declines in California, Utah and Delaware were not statistically different from expected declines based on the prior three years. In South Dakota, heart attack mortality increased 8.9 percent in the target year. Florida and New York saw bigger declines than expected but not statistically different from the 9.8 percent decline in the 44 states without a statewide smoking ban.

Variables at Work

Various factors come into play. The report notes the effect of a statewide smoke-free law “may have been muted if a large proportion of the population was already protected by pre-existing local ordinances. Such was the case in California, where city and county governments were very active in developing local ordinances, and by 1992 about 70% of the state’s population was protected. Most of these ordinances were enacted in the 1980s, so the AMI mortality rate in California might have declined more steeply than in the rest of the US during that decade. In fact, the opposite occurred. In the 1980s the age-adjusted AMI mortality rate in California declined at a slightly slower pace than the US rate.”

They conclude, “Smoke-free ordinances may serve public health objectives by providing non-smokers with indoor environments that are free from irritating and potentially harmful pollutants. However, this study does not provide evidence that hese ordinances result in a measurable immediate reduction in AMI mortality of the magnitude claimed by reports based on very small incident numbers.”