Analysis of risk factors associated with breast cancer in women: a systematic review and meta-analysis

Background: The aim of the present study was to explore the risk factors and protective factors related to breast cancer onset in women, but there is still a big debate in this respect. Therefore, it is necessary to systematically review the risk factors induced by breast cancer by using meta methods to guide clinical prevention and treatment. Methods: Studies on factors related to breast cancer onset in Chinese women were retrieved from articles from Chinese, international databases published and organizations and websites, and registers from January 2014 to January 2021. Articles were independently screened, extracted, and evaluated for quality by 2 researchers. The Cochrane Collaboration Center provided Review Manger 5.2 software [Cochrane Information Management System (IMS)] for statistical analysis, and the risk ratio of dichotic variables was adopted. Results: History of benign breast disease [odds ratio (OR) 1.03, 95% confidence interval (CI): 0.95-1.12, P=0.42], family history of breast cancer (OR: 2.02, 95% CI: 1.83-2.23, P<0.00001), menopause onset >50 years of age (OR: 1.78, 95% CI: 1.62-1.95, P<0.00001), and use of oral contraceptives (OR: 1.16, 95% CI: 1.02-1.32, P=0.02) were found to be breast cancer risk factors. The number of term pregnancies (OR: 0.80, 95% CI: 0.66-0.97, P=0.03) and breastfeeding (OR: 0.84, 95% CI: 0.74-0.96, P=0.01) were found to be protective factors for breast cancer. Conclusions: In order to control the occurrence of breast cancer, effective measures should be taken to effectively avoid related risk factors, and breastfeeding and high-risk population screening should be advocated.