Nutritional factors, physical activity, and breast cancer by hormonal receptor status

Purpose: To investigate the association between food and nutrient intake, occupational and leisure-time physical activity, and body mass index and breast cancer risk by estrogen receptor (ER) and progesterone receptor (PR) status. Methods: We analyzed data from a hospital-based case-control study conducted between 1991 and 1994 in Italy, including 1075 women with incident breast cancer and 1477 controls. Results: The associations with breast cancer risk were similar according to ER status for all risk factors considered. In particular, significant reduced risk of ER- and ER+ breast cancers were observed for raw vegetables (multivariate odds ratio, OR, for high vs low consumption: 0.6 and 0.7, respectively) and for polyunsaturated fats (OR: 0.6 and 0.7, respectively). No significant heterogeneous risk estimates were observed for combinations of ER and PR status. Conclusions: Our study does not suggest major differences risk for various dietary and lifestyle factors according to ER and PR breast cancer subtypes. (C) 2013 Elsevier Ltd. All rights reserved.