Pooled analysis of prospective cohort studies on height, weight, and breast cancer risk

The association between anthropometric indices and the risk of breast cance r was analyzed using pooled data from seven prospective cohort studies. Tog ether, these cohorts comprise 337,819 women and 4,385 incident invasive bre ast cancer cases. in multivariate analyses controlling for reproductive, di etary, and other risk factors, the pooled relative risk (RR) of breast canc er per height increment of 5 cm was 1.02 (95% confidence interval (CI): 0.9 6, 1.10) in premenopausal women and 1.07 (95% CI: 1.03, 1.12) in postmenopa usal women. Body mass index (BMI) showed significant inverse and positive a ssociations with breast cancer among pre- and postmenopausal women, respect ively; these associations were nonlinear. Compared with premenopausal women with a BMI of less than 21 kg/m(2), women with a BMI exceeding 31 kg/m(2) had an RR of 0.54 (95% CI: 0.34, 0.85). In postmenopausal women, the RRs di d not increase further when BMI exceeded 28 kg/m(2); the RR for these women was 1.26 (95% CI: 1.09, 1.46). The authors found little evidence for inter action with other breast cancer risk factors. Their data indicate that heig ht is an independent risk factor for postmenopausal breast cancer; in preme nopausal women, this relation is less clear. The association between BMI an d breast cancer Varies by menopausal status. Weight control may reduce the risk among postmenopausal women.