Obesity, often assessed at one point in time, is an established risk factor of several types of cancer, however, associations with cumulative exposure to obesity across the life course are not well understood. We investigated the relationship between combined measures of duration and intensity of premenopausal overweight and obesity and the incidence of postmenopausal breast, endometrial, and colorectal cancers in Icelandic women. Body mass index (BMI) trajectories between ages 20 and 50 of 88,809 women from the Cancer Detection Clinic Cohort were predicted using growth curve models. Indicators of overweight and obesity duration and intensity were computed and their association with risk of postmenopausal breast, endometrial, and colorectal cancers was examined using multivariate Cox models for subjects followed‐up beyond the age of 50 (n = 67,488). During a mean follow‐up of 17 years, incident events of 3,016 postmenopausal breast, 410 endometrial and 987 colorectal cancers were ascertained. Each 0.1 kg/m² per year increase in BMI between ages 20 and 50 was positively associated with risks of postmenopausal breast, endometrium and colorectal cancers with hazard ratios equal to 1.09 (95% Confidence Interval (CI):1.04–1.13), 1.31 (95% CI: 1.18–1.44) and 1.10 (95% CI: 1.00–1.21), respectively. Compared to women who were never obese, cumulative BMI × years of obesity were linearly positively associated with risk of endometrial cancer, whereas the association with breast cancer was initially positive, but leveled off with increasing cumulative BMI × years. Cumulative exposure to obesity may provide additional insights into the etiology of cancer and should be considered in future studies that assess obesity–cancer relationships.

中文翻译：

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绝经前肥胖的累积暴露和绝经后癌症的风险：一项针对冰岛妇女的基于人群的研究。


肥胖通常在某个时间点进行评估，它是多种癌症的既定危险因素，然而，与整个生命过程中累积的肥胖风险之间的关系尚不清楚。我们调查了冰岛女性绝经前超重和肥胖持续时间和强度的综合测量与绝经后乳腺癌、子宫内膜癌和结直肠癌发病率之间的关系。使用生长曲线模型预测了癌症检测诊所队列中 88,809 名女性 20 岁至 50 岁之间的体重指数 (BMI) 轨迹。计算超重和肥胖持续时间和强度的指标，并使用多元 Cox 模型对 50 岁以上的受试者进行随访，检查它们与绝经后乳腺癌、子宫内膜癌和结直肠癌风险的关系 ( n = 67,488)。在平均 17 年的随访期间，确定了 3,016 例绝经后乳腺癌、410 例子宫内膜癌和 987 例结直肠癌的事件。 20 至 50 岁之间，BMI 每增加 0.1 kg/m ²与绝经后乳腺癌、子宫内膜癌和结直肠癌的风险呈正相关，风险比等于 1.09（95% 置信区间 (CI)：1.04–1.13）、1.31 (95% CI: 1.18–1.44) 和 1.10 (95% CI: 1.00–1.21)。与从不肥胖的女性相比，肥胖的累积 BMI × 年数与子宫内膜癌的风险呈线性正相关，而与乳腺癌的相关性最初呈正相关，但随着累积 BMI × 年数的增加而趋于平稳。累积的肥胖暴露可能会为癌症的病因学提供更多的见解，并且应该在未来评估肥胖与癌症关系的研究中予以考虑。