Passive smoking and plasma fibrinogen concentrations.

To examine the effect of passive smoking on plasma fibrinogen, a coronary risk factor, a cross-sectional study was conducted between 1990 and 1993 for 1,780 Japanese women aged 45-74 years who resided in Kyowa town, Ibaraki-ken, Japan. Fibrinogen concentrations controlling for age, body mass index, ethanol intake, serum total cholesterol, diabetes mellitus, and menopausal status were 8.6 (95% confidence interval 1.6-15.6) mg/dl higher in women exposed passively to smoking outside the home (n = 435) and 11.2 (95% confidence interval 3.0-19.3) mg/dl higher in women exposed both in and outside the home (n = 272) than in women unexposed in either location (n = 524). These effects of passive smoking were about 40-60% of that of current active smoking. An effect of passive smoking at home only was small and not statistically significant. The association between fibrinogen and passive smoking was primarily observed in women aged 45-59 years but not in those aged 60-74 years. Passive smoking may raise the risk of coronary heart disease partly by increasing plasma fibrinogen concentrations.