Heart disease from passive smoking in the workplace.

OBJECTIVES This review sought to determine whether passive smoking in the workplace has roughly the same association with heart disease as passive smoking at home and to update a previous 1994 review on the effects of home-based passive exposure on the heart. BACKGROUND To predict the effects of passive smoking at work on heart disease, public agencies have had to assume that workplace exposure to tobacco smoke was equivalent to home exposure. With the availability of more workplace exposure data, it is now possible to make a direct comparison. METHODS The odds ratios and relative risks (RRs) of the eight studies that contained data on workplace exposure (1,699 cases) were arranged in what was believed to be the order of the quality of their tobacco smoke exposure measurements. A meta-analysis was performed to obtain combined RRs. Data from seven new studies on largely home-based exposure and heart disease that were not included in the 1994 review were also evaluated. RESULTS The combined RR for the three top-rated workplace studies was 1.50 (95% confidence interval [CI] 1.12 to 2.01). Adding four lower rated studies reduced the RR to 1.35 (95% CI 1.09 to 1.67). Adding the largest study but the one with questionable exposure history reduced the combined RR to 1.18 (95% CI 1.04 to 1.34). Adding the seven new, largely home-based studies increased the home-based morbidity RR to 1.49 (95% CI 1.29 to 1.72) compared with 1.42 in 1994 while leaving the mortality RR unchanged at 1.23 (95% CI 1.14 to 1.32). CONCLUSIONS The RRs for heart disease from passive smoking at work are roughly equal to those from home-based exposure.