BODY-WEIGHT - ESTIMATION OF RISK FOR BREAST AND ENDOMETRIAL CANCERS

Consistent, positive, and independent associations between body weight or body mass index (BMI), weight gain, and various measures of centra l adiposity and the incidence of endometrial cancer exist. Increases i n relative risks of 2-3.5 are reported for women with BMIs (in kg/m(2) ) greater than or equal to 28-30, for women in the fourth compared wit h the first quartile of measures of central adiposity, and for women w ith weight gains from young adulthood to middle age of greater than or equal to 27 kg. Furthermore, endometrial cancer mortality is increase d in heavier and taller women. Associations between breast cancer inci dence and these measures of adiposity vary by age and menopausal statu s at the time of diagnosis. Heavier women appear to be at decreased ri sk for developing premenopausal breast cancer; relative risks of appro ximate to 0.6 were reported for women with BMIs greater than or equal to 26-27. Conversely, heavier women are at increased risk of developin g and dying from postmenopausal breast cancer. Although contradictory findings have been observed in cohort studies, modest increases in rel ative risks on the order of 1.2-1.5 were reported in older postmenopau sal women with BMIs of greater than or equal to 28-30. Furthermore, ad ult weight gain and increased central adiposity have been consistently and independently associated with an increased risk for postmenopausa l breast cancer. No significant associations have been observed betwee n weight loss and postmenopausal breast cancer incidence. These findin gs indicate that avoidance of weight gain and accumulation of central body fat during adult life may reduce risk of both endometrial and pos tmenopausal breast cancer.