BACKGROUND Obesity is an established risk factor for several cancers. Adult weight gain has been associated with increased cancer risk, but studies on timing and duration of adult weight gain are relatively scarce. We examined the impact of BMI (body mass index) and weight changes over time, as well as the timing and duration of excess weight, on obesity- and non-obesity-related cancers. METHODS We pooled health data from six European cohorts and included 221 274 individuals with two or more height and weight measurements during 1972-2014. Several BMI and weight measures were constructed. Cancer cases were identified through linkage with national cancer registries. Hazard ratios (HRs) of cancer with 95% confidence intervals (CIs) were derived from time-dependent Cox-regression models. RESULTS During follow-up, 27 881 cancer cases were diagnosed; 9761 were obesity-related. The HR of all obesity-related cancers increased with increasing BMI at first and last measurement, maximum BMI and longer duration of overweight (men only) and obesity. Participants who were overweight before age 40 years had an HR of obesity-related cancers of 1.16 (95% CI 1.02, 1.32) and 1.15 (95% CI 1.04, 1.27) in men and women, respectively, compared with those who were not overweight. The risk increase was particularly high for endometrial (70%), male renal-cell (58%) and male colon cancer (29%). No positive associations were seen for cancers not regarded as obesity-related. CONCLUSIONS Adult weight gain was associated with increased risk of several major cancers. The degree, timing and duration of overweight and obesity also seemed to be important. Preventing weight gain may reduce the cancer risk.

中文翻译：

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BMI和体重变化以及与肥胖相关的癌症风险：一项欧洲队列研究汇总。

背景技术肥胖是几种癌症的确定的危险因素。成人体重增加与增加的癌症风险相关，但是关于成人体重增加的时间和持续时间的研究相对较少。我们研究了BMI（体重指数）和体重随时间的变化，以及超重的时间和持续时间对肥胖和非肥胖相关癌症的影响。方法我们汇总了来自六个欧洲队列的健康数据，并纳入1972-2014年期间有221 274个身高和体重测量值在两个以上的个体。构造了一些BMI和体重测量。癌症病例是通过与国家癌症登记机构建立联系而确定的。具有95％置信区间（CIs）的癌症的危险比（HRs）来自于时间依赖性Cox回归模型。结果随访期间，诊断出27 881例癌症病例。9761与肥胖有关。在首次和最后一次测量时，所有与肥胖相关的癌症的HR随BMI的增加，最大BMI和超重（仅限男性）和肥胖症的持续时间延长而增加。与未超重的参与者相比，年龄在40岁之前超重的参与者的肥胖相关癌症的HR分别为1.16（95％CI 1.02，1.32）和1.15（95％CI 1.04，1.27）。 。子宫内膜（70％），男性肾细胞（58％）和男性结肠癌（29％）的风险增加尤其高。没有被认为与肥胖相关的癌症没有发现正相关。结论成人体重增加与几种主要癌症的风险增加有关。超重和肥胖的程度，时间和持续时间似乎也很重要。预防体重增加可以降低患癌症的风险。