[INFLUENCE OF REPRODUCTIVE FACTORS, BREASTFEEDING AND OBESITY ON THE RISK OF BREAST CANCER IN MEXICAN WOMEN].

Breast cancer (BC) is considered a global public health problem, and is the most frequently type diagnosed in Mexican women. Therefore, it is important to study the risk factors associated to this neoplasia in order to establish prevention strategies. The aim of this study was to evaluate the effect of hormonal contraceptives and hormone therapy (HT) use and period of use, breastfeeding practice, abdominal obesity and weight gain in adulthood, on the risk of BC in adult women from Northwest Mexico. This was a case-control study that included 162 women (81 cases and 81 controls). A sociodemographic and health questionnaire, and a survey history of body weight were applied to participants. Measurements of body weight, height and waist circumference were performed. To assess the association between BC risk and exposing factors, a multivariate logistic regression model was used. Average age of cases and controls were 51.8 ± 11.7 and 51.4 ± 11.3 years, respectively. No significant association was found between the use and period of use of hormonal contraceptives and HT with the risk of BC. The practice of breastfeeding (OR=0.34, 95%CI: 0.12- 0.92) and the time of exclusive breastfeeding (OR=0.64, 95%CI: 0.42-0.97; crude) were protective against the risk of BC. Abdominal obesity (OR=0.93, 95%CI: 0.90-0.97) and weight gain in early adulthood (OR=0.90, 95%CI: 0.85-0.95) were inversely associated to the risk of BC. In conclusion, the practice of breastfeeding may help prevent BC in Mexican women.