TIMING OF WEIGHT-GAIN AND BREAST-CANCER RISK

Background. Obesity and body-fat distribution have been associated wit h the incidence of breast and endometrial cancers. It may be critical to determine if the timing of weight gain during periods of hormonal c hange, such as menarche, pregnancy, or menopause, has different biolog ic effects, especially secondary to differences in the localization of body fat during these periods. The objective of the current study was to determine if excess weight in any particular decade of life or the timing of weight gain was more significant relative to breast cancer risk. Methods. Anthropometric, medical, and hormonal histories were ob tained from 218 consecutively recruited, newly diagnosed patients with breast cancer admitted to the H. Lee Moffitt Cancer Center and Resear ch Institute (Tampa, FL) and 436 control subjects, matched in a two to one ratio for age and menopausal status. Results. A weight gain of 15 pounds or more was observed for 63.8% of the patients compared with 4 9.3% control subjects (P = 0.0006) from age 30 to current age. Similar ly, more than 48% of cases gained more than 15 pounds from ages 16 to 30 compared with 37% (P = 0.01) of the control population. Although we ight gain from age 16 to adulthood was significantly higher in patient s with breast cancer at each decade when compared with control subject s, a significant and independent association between weight at age 30 (P < 0.0001) and risk of breast cancer was noted. Conclusion. Women wh o progressively gain weight from puberty to adulthood, and specificall y in the third decade of life, should be considered at a higher risk f or developing breast cancer.