Epidemiologic studies of fatal and nonfatal cardiovascular disease and ETSexposure from spousal smoking

This article reviews the epidemiologic studies of the association of ischem ic heart disease risk and environmental tobacco smoke (ETS) exposure from a spouse who smokes. Seventeen studies (nine cohort, eight case-control) com prising more than 485,000 lifelong nonsmokers and 7,345 coronary heart dise ase (CHD) events were included in a meta-analysis. Together, these studies include 36% more CHD events and 58% more study subjects than were available for review by the U.S. Occupationai Safety and Health Administration (OSHA ) in 1994. The relative risk (RR) for fatal or nonfatal coronary events amo ng never smokers married to smokers, compared to those whose spouses did no r smoke, was RR = 1.25 (95% confidence interval [95% CI], 1.17-1.33) across the combined studies. This association was statistically similar in men (R R = 1.24; 95% CI, 1.15-1.32) and women (RR = 1.23; 95% CI, 1.15-1.32); in s tudies of cohort (RR = 1.23; 95% CI, 1.15-1.31) and case-control (RR = 1.47 ; 95% CI, 1.19-1.81) design; in the United Stales (RR = 1.22, 95% CI, 1.13- 1.30) and other countries (RR = 1.41; 95% CI, 1.21-1.65); and in studies of fatal (RR = 1.22; 95% CI, 1.14-1.30) and nonfatal (RR = 1.32; 95% CI, 1.04 -1.67) heart disease. in three studies that presented data separately for n onsmokers married to current or former smokers, the association was stronge r when the spouses continued to smoke (RR = 1.16, 1.06-1.28) than With form er smokers (RR = 0.98; 95% CI, 0.89-1.08). The aggregate data are unlikely to be attributable to chance, publication bias, confounding, or misclassifi cation of exposure. The evidence linking heart disease and FTS exposure fro m a spouse has become substantially stronger-since OSHA first proposed incl uding heart disease in its risk assessment of ETS in 1994.