Breast cancer risk factors in women from Santiago, Chile

Background: Epidemiological studies suggest a relation between breast cance r, diet and life styles. Aim: To analyze the association between food patte rns, obesity, smoking, alcohol consumption and breast cancer risk in women of Santiago. Patients and methods: A case-control study design (170 cases a nd 340 controls), matched by age and sex, was used. Through a food frequenc y questionnaire the average daily intake of vegetables, fruits, beta-carote ne, vitamin A, C, E and fiber was analyzed. Other exposures to non-nutritio nal risks (parity, smoking, cancer history) were also studied. Conditional logistic regression was calculated to determine the odds ratio associated w ith variations in food and nutrient intake and nonnutritional factors. Resu lts: Cases had a great BMI and a higher prevalence of obesity than controls (p< 0.02). No differences were observed in either group food patterns. The ORs for breast cancer associated with obesity and alcohol consumption were 1.65 (95% CI 1.06-2.64) and 1.61 (95% CI 1.06-2.54) respectively (p< 0.05) . Multiparity had a protective effect with 0.66 less risk (95% CI 0.44-0.99 ). No protective effect associated to a greater intake of vegetables, fruit s or natural antioxidants was observed. Multivariate analysis model disclos ed obesity as a risk factor (OR 1/79, p< 0.02) and party greater than or eq ual to 4 as protective (OR 0/62, p<0.02). Conclusions: This study does not support a protective role for natural antioxidants against breast cancer bu t indicate a weak association with obesity.