EXPOSURE TO ENVIRONMENTAL TOBACCO-SMOKE AND THE RISK OF HEART-ATTACK

Background. Environmental tobacco smoke (ETS) increases the risk of he art disease in several epidemiological studies although the methods of assessing exposure have been incomplete. We determined the prevalence of ETS from various sources, and examined the association between ETS and the risk of myocardial infarction. Methods. A hospital-based case -control study of myocardial infarction was conducted from 1980 to 199 0 by interviewing 114 case patients and 158 control subjects. Results. Among controls, the sources of ETS were the workplace (56%), childhoo d exposure (66%), home adult exposure (48%), car exposure (20%) and fr om trains or other surface transportation (4%). Compared to never smok ers, the odds ratio (OR) for exposure to ETS during childhood was 0.97 (95% confidence intervals [CI] :0.53-1.46) for men and 0.92 (95% CI : 0.5-1.86) for women. The adjusted OR associated with adult exposure wa s 1.5 (95% CI : 0.9-2.6), although no trend was observed with the numb er of years of exposure. Women who were exposed to ETS in automobiles had an increased but non-significant risk (OR = 2.8, 95% CI :0.9-8.0). Conclusion. Exposure to ETS comes from a variety of sources besides t he spouse including parents, workplace employees and motorists. Exposu re to ETS during childhood is not associated with an increased risk of heart disease. However, ETS exposure during adulthood increased the r isk of myocardial infarction approximately 50% in this data although t he findings were not statistically significant.