title: Cigarette smoking and breast cancer.
abstract: To investigate the relationship of smoking to breast cancer risk, the authors conducted a case-control study involving 1,547 patients and 1,930 controls identified between 1973 and 1980 through a nationwide screening program. There was no evidence that smoking affected risk (relative risk (RR) = 1.2), nor were there any apparent relationships with more detailed exposure measures. No substantial variations in risk were noted by menopausal status; in particular, there was no support for the notion that smoking is associated with a reduced risk among naturally menopausal women (RR = 1.1). In addition, the data provided no general evidence that smokers experience an earlier menopause than nonsmokers, even when heavy smoking was considered. Evaluation of a number of sources of confounding and effect modification failed to alter the conclusion that smoking status does not appear to alter breast cancer risk among this population.
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001943:Breast Neoplasms / Q000209:etiology*; D003276:Contraceptives, Oral / Q000009:adverse effects; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008593:Menopause; D008875:Middle Aged; D012306:Risk; D012907:Smoking
chemical_list: D003276:Contraceptives, Oral