Premenopausal Fat Intake and Risk of Breast Cancer

• Published in: JNCI : Journal of the National Cancer Institute 2003-07, Vol.95 (14), p.1079-1085
• Main Authors: Cho, Eunyoung, Spiegelman, Donna, Hunter, David J., Chen, Wendy Y., Stampfer, Meir J., Colditz, Graham A., Willett, Walter C.
• Format: Article
• Language: English
• Subjects: Adult; Breast cancer; Breast Neoplasms - chemically induced; Breast Neoplasms - etiology; Dairy Products - adverse effects; Dietary Fats - administration & dosage; Dietary Fats - adverse effects; Female; Health risk assessment; Humans; Meat - adverse effects; Menopause; Middle Aged; Multivariate Analysis; Oils & fats; Premenopause; Risk Assessment; Risk Factors
• ISSN: 0027-8874; 1460-2105
• DOI: 10.1093/jnci/95.14.1079

Background: International comparisons and case–control 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 supported 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 cancer 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 cancer. Relative to women in the lowest quintile of fat intake, women in the highest quintile of intake had a slight increased risk of breast cancer (RR = 1.25, 95% CI = 0.98 to 1.59; Ptrend = .06). The increase was associated with intake of animal fat but not vegetable fat; RRs for the increasing quintiles of animal fat intake were 1.00 (referent), 1.28, 1.37, 1.54, and 1.33 (95% CI = 1.02 to 1.73; Ptrend = .002). Intakes of both saturated and monounsaturated fat were related to modestly elevated breast cancer risk. Among food groups contributing to animal fat, red meat and high-fat dairy foods were each associated with an increased risk of breast cancer. Conclusions: Intake of animal fat, mainly from red meat and high-fat dairy foods, during premenopausal years is associated with an increased risk of breast cancer.