[Population-attributable risk estimates for breast cancer in Chinese females].

OBJECTIVE: To estimate the contribution of known identified risk factors to breast cancer incidence and mortality in China, and provide evidence to support the prevention and control of breast cancer for Chinese females. METHODS: We calculated the proportion of breast cancer attributable to specific risk factors. Data on exposure prevalence were obtained from Meta-analyses and large-scale national surveys of representative samples of the Chinese population. Data on relative risks were obtained from Meta-analyses and large-scale prospective studies. Cancer mortality and incidence were taken from the Third National Death Survey and from cancer registries in China. RESULTS: The first 5 risk factors of breast cancer in China were benign breast disease (RR = 2.62), family history of breast cancer (RR = 2.39), smoking (RR = 1.86), overweight (RR = 1.60) and age at menarche (RR = 1.54). The proportion of breast cancer deaths attributable to reproductive factors, lifestyle factors, benign breast disease, the use of external hormone and family history of breast cancer was 27.84%, 23.55%, 15.09%, 3.60% and 2.49%, respectively. The total population attributable fraction (PAF) was 55.95% for risk factors in our study. Overall, we estimated that 79 862 breast cancer cases and 22 456 deaths were attributed to the five risk factors in China in 2005. CONCLUSIONS: The prevention and control of unhealthy lifestyle factors may significantly reduce the number and death of breast cancer in China.