Overeating, caloric restriction and breast cancer risk by pathologic subtype: the EPIGEICAM study.

Abstract

This study analyzes the association of excessive energy intake and caloric restriction with breast cancer (BC) risk taking into account the individual energy needs of Spanish women. We conducted a multicenter matched case-control study where 973 pairs completed lifestyle and food frequency questionnaires. Expected caloric intake was predicted from a linear regression model in controls, including calories consumed as dependent variable, basal metabolic rate as an offset and physical activity as explanatory. Overeating and caloric restriction were defined taking into account the 99% confidence interval of the predicted value. The association with BC risk, overall and by pathologic subtype, was evaluated using conditional and multinomial logistic regression models. While premenopausal women that consumed few calories (>20% below predicted) had lower BC risk (OR = 0.36; 95% CI = 0.21-0.63), postmenopausal women with an excessive intake (≥40% above predicted) showed an increased risk (OR = 2.81; 95% CI = 1.65-4.79). For every 20% increase in relative (observed/predicted) caloric intake the risk of hormone receptor positive (p-trend 20% below predicted) had lower BC risk (OR = 0.36; 95% CI = 0.21-0.63), postmenopausal women with an excessive intake (≥40% above predicted) showed an increased risk (OR = 2.81; 95% CI = 1.65-4.79). For every 20% increase in relative (observed/predicted) caloric intake the risk of hormone receptor positive (p-trend