Premenopausal Fat Intake and Risk of Breast Cancer

studies have suggested a positive relation between dietary fat intake and breast cancer risk, but prospective studies, most of them involving postmenopausal women, have not sup-ported this association. We conducted a prospective analysis of the relation between dietary fat intake and breast cancer risk among premenopausal women enrolled in the Nurses’ Health Study II. Methods: Dietary fat intake and breast can-cer risk were assessed among 90 655 premenopausal women aged 26 to 46 years in 1991. Fat intake was assessed with a food-frequency questionnaire at baseline in 1991 and again in 1995. Breast cancers were self-reported and confirmed by review of pathology reports. Multivariable relative risks (RRs) and 95 % confidence intervals (CIs) were calculated. All statistical tests were two-sided. Results: During 8 years of follow-up, 714 women developed incident invasive breast