How acute and reversible are the cardiovascular risks of secondhand smoke?

Could eating in a smoky restaurant precipitate an acute myocardial infarction in a non—smoker? As unlikely as this sounds, a growing body of scientific data suggests that this is possible. In this context, the results of the observational study in Helena, MT are provocative: hospital admissions for acute myocardial infarction declined by about 40% during the six months in which a comprehensive local ordinance on clean air was in effect, and rebounded after the ordinance was suspended.1 Given the small size and observational design of the study, these findings might be discounted or even disregarded altogether. However, the study focuses attention on an interesting subset of literature on secondhand smoke and its consequences. We now have a considerable amount of epidemiological literature and laboratory data on the mechanisms by which relatively small exposures to toxins in tobacco smoke seem to cause unexpectedly large increases in the risk of acute cardiovascular disease.2–7 Exposure to secondhand smoke increases the risk of fatal and non-fatal coronary heart disease in non-smokers by about 30%.2 5 8 9 Because coronary heart disease is a leading cause of death in many countries, even relatively small increases in risk from this one factor can result in a large population burden of disease attributable to exposure to tobacco smoke.10 11 While the substantial cardiovascular risks posed by active smoking are now almost universally accepted, the tobacco industry and some other observers continue to question the idea that secondhand smoke can cause cardiovascular disease and death.12–15 Notwithstanding the substantial clinical and experimental evidence regarding the adverse cardiovascular effects of exposure to secondhand smoke, some have argued that an association between low level environmental exposures and health outcomes should be more critically evaluated, particularly when the relative risk for the exposure …