Division of Clinical Epidemiology and Aging Research, German Cancer Research Center, Im Neuenheimer Feld 581, D-69120, Heidelberg, Germany.
Medical Faculty Heidelberg, Heidelberg University, Heidelberg, Germany.
Eur J Epidemiol. 2024 Sep;39(9):991-1003. doi: 10.1007/s10654-024-01146-0. Epub 2024 Sep 18.
To evaluate the magnitude of the potential underestimation of the proportion of cancer cases attributable to excess weight, known as population attributable fraction (PAF), due to potential bias from prediagnostic weight loss already present at baseline of cohort studies and to overcome it as much as possible.
Data from the UK Biobank cohort participants aged 40-69 without prior cancer diagnosis were analyzed. We assessed the magnitude of associations of excess weight with the incidence of obesity-related cancers combined, and separately for gastrointestinal (GI) and other cancers. Using multivariable Cox proportional hazards models, hazard ratios (HR) and their 95% confidence intervals (CI), and PAFs for excess weight at baseline were estimated for various periods of time after weight measurements.
Of 458,660 participants, 20,218 individuals developed obesity-related cancers during a median 11.0-year follow-up, comprising 8,460 GI, and 11,765 non-GI cancers. PAFs were much higher for cancers occurring more than four years after recruitment than for cancers occurring within the initial four years: 17.7% versus 7.2%, 21.4% versus 11.7% for GI, non-GI and all obesity-related cancers combined, respectively. With respect to total cancer (including cancers with no established relationship with excess weight), PAFs were estimated as 5.1% and 8.8% for the 0-4 and 4-14-year periods of follow-up.
The proportion of cancers attributable to excess weight is likely substantially larger than previously estimated based on cohort studies with short follow-up time or no or only limited exclusion of the early years of follow-up from the analyses.
评估由于队列研究基线时已经存在的预测性体重减轻所导致的潜在偏倚对超重归因比例（PAF）的癌症病例估计值低估的程度，并尽可能克服这一偏倚。
分析了英国生物库队列研究中年龄在 40-69 岁、无先前癌症诊断的参与者的数据。我们评估了超重与肥胖相关癌症综合发病率以及胃肠道（GI）和其他癌症发病率的相关性的大小。使用多变量 Cox 比例风险模型，估计了基线时超重的危险比（HR）及其 95%置信区间（CI）和 PAF ，用于体重测量后不同时间段的肥胖相关癌症。
在 458660 名参与者中，20218 人在中位 11.0 年的随访期间患上了肥胖相关癌症，包括 8460 例胃肠道癌症和 11765 例非胃肠道癌症。与招募后 4 年以上发生的癌症相比，4 年内发生的癌症的 PAF 要高得多：胃肠道癌症、非胃肠道癌症和肥胖相关癌症的 PAF 分别为 17.7%、21.4%和 11.7%。对于所有癌症（包括与超重没有明确关系的癌症），0-4 年和 4-14 年的 PAF 分别估计为 5.1%和 8.8%。
与随访时间短或没有或仅有限地排除随访早期的队列研究相比，基于肥胖与癌症相关性的研究结果，超重导致的癌症比例可能要大得多。
