[Reproductive risk factors associated with breast cancer in Colombian women]. / Factores de riesgo reproductivo asociados al cáncer mamario, en mujeres colombianas.

INTRODUCTION: As of 1992, breast cancer has been the second cause of death in Columbian women, with a rising trend in mortality due to this type of neoplasm (average annual rate 4.5*/100.000 inhabitants). Information about potential risk factors for breast cancer in Latin American countries is scarce. The objectives of the project were to test the breastfeeding protection against breast cancer and to establish the reproductive factors associated with breast cancer in Columbia. METHODS: A hospital case-control study was carried out from July 1995 to March 1996 in Bogotá, Columbia, using paring by age groups. The study population consisted of 171 histopathologically confirmed cases and 171 controls. Reproductive history and sociodemographic data were collected through a questionnaire, and logistic regression models were used for statistical analysis of the data. RESULTS: The following associated factors were found as principal results: nuli-parousness as compared with women with over 3 children (OR=3.35 CI 1.40-8.0), age at first birth (OR=1.83 CI 0.70- 4.80), breast cancer history, breastfeeding the first child (OR=0.09 CI 0.01-0.64 for 1-11 months) and with a highly significant trend for accumulated breastfeeding above 24 months (p=0.001). CONCLUSIONS: This study indicates the importance of focusing on the promotion of prolonged breastfeeding by women identified as being at higher risk, and confirms that socio-economic level can determine life styles and reproductive events among women (such as breastfeeding time); this could explain the increase in breast cancer mortality in Latin American countries, similar to that in developed countries in terms of fertility and risk factors for breast cancer. The epidemiological information produced by this study will be useful for planning and carrying out early diagnosis and treatment of breast cancer in women identified as being at high risk of this disease.