Résumé :
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[BDSP. Notice produite par INIST 8R0xBVw0. Diffusion soumise à autorisation]. Context Oral contraceptive (OC) use is weakly associated with breast cancer risk in the general population, but the association among women with a familial predisposition to breast cancer is less clear. Objective To determine whether the association between OC use and risk of breast cancer is influenced by family history of the disease. Design and Setting Historical cohort study of 426 families of breast cancer probands diagnosed between 1944 and 1952 at the Tumor Clinic of the University of Minnesota Hospital. Follow-up data on families were collected by telephone interview between 1991 and 1996. Participants A total of 394 sisters and daughters of the probands, 3002 grand-daughters and nieces, and 2754 women who married into the families. Main Outcome Measure Relative risk (RR) of breast cancer associated with history of OC use by relationship to proband. Results After accounting for age and birth cohort, ever having used OCs was associated with significantly increased risk of breast cancer among sisters and daughters of the probands (RR, 3.3 ; 95% confidence interval [Cl], 1.6-6.7), but not among grand-daughters and nieces of the probands (RR, 1.2 ; 95% Cl, 0.8-2.0) or among marry-ins (RR, 1.2 ; 95% Cl, 0.8-1.9). Results were essentially unchanged after adjustment for parity, age at first birth, age at menarche, age at menopause, oophorectomy, smoking, and education. (...)
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