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

PurposeTo 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.MethodsWe 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.ResultsThe 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.ConclusionsOur study does not suggest major differences risk for various dietary and lifestyle factors according to ER and PR breast cancer subtypes.