Abstract 2830: Energy balance and breast cancer risk among sisters pairs in the Breast Cancer Family Registry Study

Abstract

Abstract Animal models have shown strong evidence that energy restriction inhibits mammary tumor development. Nevertheless, epidemiologic studies in humans generally do not support an association between energy intake and breast cancer risk. Failure to take into consideration the integrated effect of energy intake, physical activity and body size may obscure the true effect of energy intake on breast cancer risk. We analyzed the combined effects of energy intake, body size and physical activity on the risk of breast cancer among 4,564 women diagnosed with breast cancer between 1995 and 2006 and 3,411 of their unaffected sisters enrolled in the Breast Cancer Family Registry. Dietary data were collected using the food frequency questionnaire developed for the Hawaii-Los Angeles Multiethnic Cohort. Conditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI). We observed an overall 50% increased risk of breast cancer among women in the highest quartile of energy intake compared to those in the lowest quartile (OR=1.5, 95% CI: 1.1-2.2, ptrend < 0.01). The association with energy intake was limited to women with lower levels of strenuous physical activity (OR=1.9, 95% CI: 1.3-2.9 for < 1.75 hours/week during the past three years), and was stronger among women with higher body mass index (BMI) (OR=2.2, 95% CI: 0.6-7.7 for BMI ≥ 30; OR=1.5, 95% CI: 0.6-3.7 for BMI 25-29; OR=1.3, 95% CI: 0.7-2.5 for BMI < 25 kg/m2). Our results suggest that higher total energy intake in adulthood is associated with a 50% increase in breast cancer risk compared to sisters with lower energy intake in adulthood; these associations are stronger among less active and obese women. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2830.