Risk factors of breast cancer in Mexican women

Abstract

Objective. To investigate the association between family history (FH) of neoplasia, gyneco-obstetric factors and breast cancer (BC) in a case-control study. In cases, to analyze those variables in relation with early onset of BC, the manner of detection (self-examination, prompted by pain, or casual), the size of tumor, and the elapsed time to seek medical attention. Material and methods. Data from 151 prevalent BC cases and 235 age-matched controls were analyzed by multiple logistic regression, to assess the influence of BC risk factors. Results: Ten per cent of patients and 1% of controls had first- degree relatives (FDR) with BC. Family history of FDR with BC (OR, 11.2; 95% Cl 2.42-51.92) or with gastric or pancreatic cancer (OR, 17.7; 95% Cl 2.2- 142.6) was associated with BC risk. Breastfeeding at or under 25 years of age was protective against BC (OR, 0.40; 95% Cl 0.24-0.66). The manner of tumor detection did not influence its size at the time of diagnosis. Conclusions. Our study confirms that FH of BC and/or of gastric or pancreatic carcinoma are risk factors for BC, while lactation at 25 years of age or earlier is protective.