中国学者发现二型糖尿病患者体重指数与老年女性乳腺癌风险相关性

肥胖和糖尿病是癌症的两个风险因素，评估糖尿病患者体重指数与癌症风险的关系，可以提高目前对其潜在机制的认识。

2018年8月6日，英国《生物医学中心》癌症分册在线发表复旦大学公共卫生学院、公共卫生安全教育部重点实验室、国民健康社会风险预警协同创新中心、上海市闵行区疾病预防控制中心、上海市疾病预防控制中心、洛杉矶加利福尼亚大学费尔丁公共卫生学院的大数据研究报告，分析了2型糖尿病中国患者体重指数与癌症风险的相关性。

该队列回顾研究将中国上海市闵行区居民电子健康档案数据库5万1004例新诊断2型糖尿病患者，与上海市癌症登记数据和上海市人口统计数据进行关联，确定了2015年9月30日之前发生的偶发癌症事件和全因死亡事件。通过多因素比例风险回归模型±受限三次样条函数，分析体重指数与癌症风险可能存在的非线性和线性关系。

结果发现，对于60岁以下男性，体重指数与所有癌风险之间存在非线性关系（非线性P=0.009）。体重指数为25.0kg/m²与体重指数较低或较高的患者相比，癌症风险增加。

对于60岁以上女性，体重指数与所有癌和乳腺癌的风险之间存在线性量效关系，体重指数每增加1kg/m²：

所有癌风险增加3%（95%置信区间：1%～5%）

乳腺癌风险增加7%（95%置信区间：1%～13%）

体重指数与其他常见部位癌症之间未见显著相关性。

因此，该研究结果表明，体重指数对于中国2型糖尿病患者癌症风险的影响，可能因性别、年龄、癌症亚型而异，尤其对于女性、老年、乳腺癌的影响较大，提示可能存在不同的生物学机制。

BMC Cancer. 2018 Aug 6;18(1):795.

Body mass index and cancer risk among Chinese patients with type 2 diabetes mellitus.

Xu HL, Zhang ML, Yan YJ, Fang F, Guo Q, Xu DL, Zhang ZF, Zhang F, Zhao NQ, Xu WH, Qin GY.

School of Public Health, Fudan University, Shanghai, China; Shanghai Minhang Center for Disease Control and Prevention, Shanghai, China; UCLA Fielding School of Public Health, Los Angeles, CA, USA; Shanghai Municipal Center for Disease Control and Prevention, Shanghai, China; Key Laboratory of Public Health Safety, Fudan University, Shanghai, China; Collaborative Innovation Center of Social Risks Governance in Health, Fudan University, Shanghai, China.

BACKGROUND: Obesity and diabetes are two risk factors for cancer. To evaluate the association of body mass index (BMI) with cancer risk in diabetic patients may improve current understanding of potential mechanisms.

METHODS: A retrospective cohort study was conducted in 51,004 newly diagnosed T2DM patients derived from an electronic health record (EHR) database of Minhang district in Shanghai, China. Incident cancer cases and all-cause deaths occurred before September 30, 2015 were identified by linking with the Shanghai Cancer Registry and the Shanghai Vital Statistics. To examine the potential non-linear and linear relationships of BMI and cancer risk, Cox proportional hazard models with and without restricted cubic spline functions were used, respectively.

RESULTS: A non-linear association was observed between BMI and overall cancer incidence in men younger than 60 years old (p for non-linearity=0.009). Compared with those having BMI of 25.0 kg/m², the cancer risk increased in those with either lower or higher BMI. In women older than 60 years old, linear dose-response relationships were observed between BMI and the risk of both overall cancer and breast cancer. As each unit increase in BMI, the overall cancer risks elevated by 3% (95%CI: 1-5%) and the breast cancer risks increased by 7% (95%CI: 1-13%). No significant association was observed between BMI and other common cancer sites.

CONCLUSIONS: Our results show that the effect of BMI on cancer risk in Chinese patients with T2DM may vary by gender, age and cancer subtypes, suggesting different underlying biological mechanisms.

KEYWORDS: Body mass index; Cancer incidence; Retrospective cohort study; Type 2 diabetes mellitus

PMID: 30081866

DOI: 10.1186/s12885-018-4675-0