[Comprehensive evaluation and trend prediction of risk factors on breast cancer]

To comprehensively analyse and evaluate the risk factors and to predict the trend of breast cancer in China.

Collecting the articles on case-control studies related to breast cancer in the last 10 years in China. Calculating the relative risk (OR) and 95% confidence interval (95%CI) of risk factors by the random effect model of Meta-analysis to estimate present and future population attributable risk percent (PARP) based on the exposure rate of risk factor and to predict the change of incidence rates of breast cancer during the following 5 years with the change of exposure rates.

Twenty-two articles referred to case-control studies on breast cancer were selected. The OR and its 95%CI of the first 5 risk factors of breast cancer in China were benign breast lesion 3.39 (2.97 - 3.86), psychological stimulation 2.36 (2.09 - 2.67), breast-feeding 1.95 (1.54 - 2.47), family history of tumor 1.84 (1.63 - 2.08) and menstruation 1.65 (1.44 - 1.89). The factors with higher PRAP were benign breast lesion, breast-feeding, psychological stimulation with PRAR 15.47%, 15.17%, 13.76%, respectively. Their PRAP would have decreased to 12.77%, 11.32%, 12.52% and 9.90%, 8.74%, 9.69% respectively if the exposure rates had decreased 20% and 40% in the next 5 or 10 years. Factors contributing to the change of incidence rate of breast cancer would include benign breast lesion, breast-feeding, psychological stimulation along with the change of exposure rate. The incidence rates of breast cancer would then have become 3.09%, 2.75%, 3.03% and 6.19%, 5.50%, 6.07% respectively if their exposure rate had decreased 20% and 40% in the next 5 or 10 years.

Decreasing benign breast lesion, avoiding psychological stimulation, advocating on breast-feeding seemed to be the effective measures to control the occurrence and development of breast cancer.