[Metabolic syndrome components and breast cancer risk in Chinese females: a population based prospective study]

Objective: To investigate the relationship between metabolic syndrome (MS) and the risk of breast cancer in Chinese females. Methods: From May 2006 to December 2015, based on the Kailuan Women's Dynamic Cohort,a total of 25 618 female employees and retirees of the Kailuan Group were included and followed. Questionnaire surveys, physical measurements and laboratory tests were used to collect baseline sociodemographic characteristics, height, weight, blood glucose, blood lipids, blood pressure, tumor incidence and outcome information. Cox proportional hazards regression models were used to analyze the relationship between MS and its components (body mass index, blood pressure, blood glucose and blood lipid) and the risk of breast cancer in females. Results: The age of 25 618 women was (47.65±12.02) years old and median follow-up time was 8.78 years; 235 new cases of breast cancer were detected, and the incidence density was 113.19/100 000 person-years. After adjusting for age, education, income, smoking status, drinking status and other factors, people who were overweight or obese had a higher risk of breast cancer, with HR (95%CI) about 1.47 (1.12-1.93), than those with normal body mass index. Compared with those without MS abnormal components, women with two MS abnormal components had an increased risk of breast cancer (HR=1.70, 95%CI: 1.16-2.50). With the increase of the number of MS abnormal components, the risk of breast cancer increased gradually (P_trend value<0.05). Conclusion: Overweight/obesity and the number of abnormal components of MS can increase the risk of breast cancer in women.