Alcohol Consumption as a Risk Factor for Breast Cancer Development: A Case-Control Study in Brazil

Abstract

Background: Alcohol consumption is a well-established risk factor for breast cancer, but the evidence is mostly<br />from developed countries. Brazil is going through a rapid demographic expansion, and studies of this relationship are<br />also needed in such unexplored settings. Methods: We assessed the relationship between alcohol consumption and<br />breast cancer risk among 1,506 Brazilian women (406 cases and 1,100 controls). Regression models were used to<br />calculate odds ratios (OR) and 95% confidence intervals (CI). All statistical tests were two-tailed. Results: The mean<br />age of the 1,506 women was 42.0 (standard deviation, ±15.0) years. There was a significant association between breast<br />cancer and age, body mass index, age at menarche, menstrual flow and menstrual cycle. Multivariate analysis showed<br />an increased risk of invasive breast cancer in regular alcohol consumers (years old: OR 3.9; 95% CI 1.2–13.4) compared with abstainers or occasional drinkers. Women with a regular alcohol<br />intake for 10 years or more who were less than 50 years old had a threefold higher risk of developing breast cancer<br />(OR 3.0; 95% CI 1.2–7.6). Conclusion: Regular alcohol consumption increases the risk of breast cancer mainly among<br />women less than 50 years old.