Division of Epidemiology and Prevention, Aichi Cancer Center Research Institute, Nagoya, Japan.
Ann Oncol. 2012 Feb;23(2):479-90. doi: 10.1093/annonc/mdr143. Epub 2011 May 19.
Obesity has been recognized as important risk factors for colorectal cancer. However, limited evidence is available on colorectal cancer and body mass index (BMI) in Asian population.
We conducted a pooled analysis of eight population-based prospective cohorts studies in Japan with more than 300,000 subjects to evaluate an impact of obesity in terms of BMI on colorectal cancer risk with unified categories. We estimated summary hazard ratio (HR) by pooling of study-specific HR for BMI categories with random effect model.
We found a significant positive association between BMI and colorectal cancer risk in male and female. Adjusted HRs for 1 kg/m(2) increase were 1.03 [95% confidence interval (CI) 1.02-1.04] for males and 1.02 (95% CI 1.00-1.03) for females. The association was stronger in colon, especially in proximal colon, relative to rectum. Males showed a stronger association than females. Population attributable fraction for colorectal cancer by BMI ≥ 25 kg/m(2) was 3.62% (95% CI 1.91-5.30) for males and 2.62% (95% CI 0.74-4.47) for females.
We found significant association between BMI and colorectal cancer risk by pooling of data from cohort studies with considerable number of subjects among Japanese population. This information is important in cancer control planning, especially in Asian population.
肥胖已被认为是结直肠癌的重要危险因素。然而，亚洲人群中关于结直肠癌与体重指数（BMI）的证据有限。
我们对日本的 8 项基于人群的前瞻性队列研究进行了汇总分析，这些研究纳入了超过 30 万名受试者，旨在评估肥胖（BMI）对结直肠癌风险的影响，并采用统一的分类标准。我们采用随机效应模型对每个研究中 BMI 类别与结直肠癌风险的特定 HR 进行汇总，以评估肥胖与结直肠癌风险的相关性。
我们发现 BMI 与男性和女性的结直肠癌风险呈显著正相关。男性和女性中 BMI 每增加 1kg/m²，调整后的 HR 分别为 1.03（95%置信区间 1.02-1.04）和 1.02（95%置信区间 1.00-1.03）。与直肠癌相比，这种相关性在结肠癌中更强，尤其是在近端结肠中。男性的相关性强于女性。BMI≥25kg/m² 导致结直肠癌的人群归因分数（PAR）为男性 3.62%（95%置信区间 1.91-5.30）和女性 2.62%（95%置信区间 0.74-4.47）。
我们通过汇总日本人群中相当数量的队列研究数据，发现 BMI 与结直肠癌风险之间存在显著关联。这些信息对于癌症防控规划非常重要，特别是在亚洲人群中。
