Breast Cancer Risk Factors: A Case-control Study in Iranian Women

Background: Breast cancer is the most frequent malignancy and the leading cause of cancer-related death among women all around the world. In Iran, the mean age of the patients is approximately 10 years younger than that in other countries. We conducted the present study to assess the risk factors of breast cancer among Iranian women in Mashhad. Method: This case-control study was carried out between February 2016 and January 2018 on 460 women (230 cases and 230 controls), in the academic hospitals of Mashhad. The data from our cases and controls were collected and analyzed using SPSS version 18.0 software (SPSS Inc., Chicago, IL, USA). We employed logistic regression models and frequency tables to estimate odds ratio (OR) and to examine the predictive effect of each factor on breast cancer risk. P<0.05 was considered to be significant. Results: According to multivariate analysis, there was significant associations between breast cancer risk and body mass index (BMI) (Odds ratio (OR), 1.1; 95% Confidence interval (CI), 1.0-1.2), age at menarche (OR, 0.56; 95% CI, 0.47-0.68), menopausal age (OR, 1.1; 95% CI, 1.0-1.1), family history of non-breast malignancies (OR, 7.9; 95% CI, 2.2-21.1), and oral contraception pills (OR, 3.1; 95% CI, 8.34-1.16). Conclusion: This study revealed that age at menarche, family history of non-breast cancer malignancies, BMI, menopausal age, and oral contraception pills were significantly associated with breast cancer.