Passive smoking and coronary heart disease: a brief review

1. Whether passive smoking or environmental tobacco smoke (ETS) can cause coronary heart disease (CHD) is controversial. We have undertaken a comprehensive review of the epidemiological studies regarding the relationship between ETS and CHD. 2. We searched for all original papers and reviews and calculated pooled odds ratio using the Mantel-Haenszel method. 3. Ten prospective studies, nine case-control studies and one cross-sectional study were found. Almost all studies showed positive associations between ETS and CHD and a few were statistically significant, with dose-response relationships being evident. Six review papers calculated pooled estimates of the relative risks, which ranged from 1.23 to 1.51. Other studies also showed that ETS could have other cardiovascular effects. 4. The association observed is likely to be real. The criteria for causation of time sequence, consistency, coherence and biological plausibility are satisfied. We conclude that ETS may cause CHD, particularly in women who have never smoked.