Relation of environmental tobacco smoke to diet and health habits: Variations according to the site of exposure

It has been postulated that the relationship of environmental tobacco smoke (ETS) exposure to cancer or cardiovascular diseases may be confounded by s ocial class or diet because women exposed to ETS by their smoker spouse bel ong to lower social classes and have an unhealthy diet. In a population sur vey in Geneva, Switzerland, 914 female never-smokers were interviewed about sociodemographic factors, health habits including a semiquantitative food frequency questionnaire, and exposure to ETS according to the site (home, w ork, leisure). Compared to women unexposed to ETS, those exposed to ETS at work ate less fibers, cereals, vegetables, lean meat, had a lower intake of iron and beta-carotene, and had a lower total energy intake; women exposed during leisure time ate less cereals, drank less skim milk, and had a lowe r intake of complex carbohydrates. But the diet of women exposed at home di d not differ from the diet of those unexposed to ETS. Thus, "living with a smoker" in Geneva does not necessarily imply adopting his health and dietar y habits. We conclude that confounding factors of the association of ETS an d disease vary according to site and populations and therefore should not b e invoked as a systematic source of bias in all studies. I CLIN EPIDEMIOL 5 2;11:1055-1062, 1999. (C) 1999, Elsevier Science Inc. All rights reserved.