Breast cancer risk factors that are identical and differential associated with menopause status of women in Northeast Brazil

Abstract

Background: This case-control study was aimed at the identification of factors that modify breast cancer risk in a population from Northeastern Brazil. Breast cancer risk factors in this population are poorly understood. Methods: Data of 291 patients with invasive breast cancer and 291 healthy controls were obtained from medical records and personal interviews. Odds ratios (OR) and confidence intervals (CI) were determined using univariate and multiple regression analysis. Results: Oral contraceptive use increased the risk of breast cancer among pre- and post-menopause women 3.661 (95% CI: 1.81-7.39; p < 0.001) and 3.086 (95%CI: 1.85-5.79; p < 0.001) times. Family history increased the risk of breast cancer among pre- and post-menopause women 3.791 (95%CI: 1.85-7.77; p < 0.001) and 3.538 (95%CI: 2.16-5.79; p = 0.000) times. Risk of breast cancer among post-menopause women who regularly consumed alcohol was 4.21 (95%CI: 2.08-8.50; p < 0.001) times increased compared to women who did not consume alcohol. Obese and overweight post-menopause women had 2.117 (95%CI: 1.15-3.88) and 1.217 (95%CI: 0.74-2.19) times increased risk, compared to women with normal weight ( p = 0.044). Waist-to-hip ratio > 0.8 increased the risk of breast cancer among pre- menopause women 2.026 (0.94-4.38; p = 0.067) times in the univariate analysis. Nulliparous post-menopause women had 2.667 (95%CI: 1.30-5.50; p = 0.070) times increased risk. Univariate analysis of nulliparity among pre-menopause women indicated 2.59 (OR= 0.386; 95%CI: 0.15-0.98; p = 0.038) times decreased risk. Conclusions: Oral contraceptive use, family history and alcohol consumption increased the risk of breast cancer among pre- and post-menopause women. High body mass index increased the risk only among post-menopause women, whereas unadjusted high waist-to-hip ratio increased the risk of pre- menopause women. Nulliparous pre-menopause women tended to have decreased risk, whereas nulliparous post-menopause women tended to have increased risk of breast cancer.