BREAST MAMMOGRAPHIC PATTERN - A CONCATENATION OF CONFOUNDING AND BREAST-CANCER RISK-FACTORS

A mammographic pattern of >25% radiodensity is associated with increas ed risk for breast cancer. Mammographic pattern is influenced by age, body weight, reproductive factors, and race/ethnicity, The interaction among these factors in predicting breast radiographic pattern, and th eir association with the presence of histologic markers of increased r isk of breast cancer, is poorly defined. To elucidate the relations am ong epidemiologic, radiographic, and histologic markers of breast canc er risk, the authors studied these factors in an unselected forensic a utopsy series, accumulated between 1978 and 1983, of 486 women aged 15 -98 years at death. Older age and/or postmenopausal status was the str ongest predictor of radiolucent breast pattern, Obesity, defined as a Quetelet index (weight (kg)/height (m)(2)) of >25, and large breast si ze were also highly significant predictors of breast radiolucency. Fac tors related to parity were not significant predictors of breast paren chymal pattern. Native American race was an independent predictor of b reast radiolucency in this population, A dense parenchymal pattern was associated with increased prevalence of marked cystic change and the presence of duct epithelial hyperplasia in women under age 35. The res ults support the association of breast radiodensity with ethnic/racial , reproductive, and histologic factors predictive of cancer risk, Howe ver, this association is overshadowed by the effects of obesity and ag ing or menopause.