Coffee intake and breast cancer risk in the NIH-AARP diet and health cohort study
A partir des données de la cohorte "NIH-AARP Diet and Health Study" incluant 198 404 femmes agées de 50 à 71 ans, cette étude américaine évalue l'association entre la consommation de café et le risque de cancer du sein
Abstract There are several biologic mechanisms whereby coffee might reduce breast cancer risk. Caffeine and caffeic acid, major coffee constituents, have been shown to suppress mammary tumor formation in animal models and to inhibit DNA methylation in human breast cancer cells, respectively. Coffee may also reduce risk through decreasing inflammation and influencing estrogen metabolism. However, epidemiologic studies have been inconsistent and few studies have examined the association by estrogen and progesterone receptor (ER/PR) status. We evaluated coffee intake for its effect on incident breast cancer in the NIH-AARP Diet and Health Study cohort, which included 198,404 women aged 50-71 with no history of cancer, who in 1995-1996 completed a questionnaire capturing usual coffee intake over the past year. State cancer registry and mortality index linkage identified 9,915 primary incident breast carcinomas through December 2006; available information on hormone receptor status identified 2,051 ER+/PR+ and 453 ER-/PR- cancers. In multivariate proportional hazards models, coffee intake was not associated with breast cancer risk (p-value for trend=0.38) (relative risk=0.98, 95% confidence interval: 0.91-1.07, for ≥4 cups per day as compared to women who never drank coffee), and results did not vary by body mass index or history of benign breast biopsy (p-value for interaction >0.10). We found no evidence of a relationship with either caffeinated or decaffeinated coffee. Null findings persisted for risk of both hormone receptor positive and negative breast cancers. These findings from a large prospective cohort do not support a role of coffee intake in breast carcinogenesis.