Karahalios Amalia, Simpson Julie A, Baglietto Laura, MacInnis Robert J, Hodge Allison M, Giles Graham G, English Dallas R
Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Bouverie Street, Melbourne, 3010, Australia.
Cancer Epidemiology Centre, Cancer Council Victoria, 615 St Kilda Road, Melbourne, 3004, Australia.
BMC Cancer. 2016 Feb 25;16:157. doi: 10.1186/s12885-016-2144-1.
Studies reporting the association between change in weight or body mass index during midlife and risk of colorectal cancer have found inconsistent results, and only one study to date has reported the association between change in waist circumference (a measure of central adiposity) and risk of colorectal cancer.
We investigated the association between risk of colorectal cancer and changes in directly measured waist circumference and weight from baseline (1990-1994) to wave 2 (2003-2007). Cox regression, with age as the time metric and follow-up starting at wave 2, adjusted for covariates selected from a causal model, was used to estimate the Hazard Ratios (HRs) and 95 % Confidence Intervals (CIs) for the change in waist circumference and weight in relation to risk of colorectal cancer.
A total of 373 cases of colorectal cancer were diagnosed during an average 9 years of follow-up of 20,605 participants. Increases in waist circumference and weight were not associated with the risk of colorectal cancer (HR per 5 cm increase in waist circumference = 1.02; 95 % CI: 0.95, 1.10; HR per 5 kg increase in weight = 0.93; 0.85, 1.02). For individuals with a waist circumference at baseline that was less than the sex-specific mean value there was a slight increased risk of colorectal cancer associated with a 5 cm increase in waist circumference at wave 2 (HR = 1.08; 0.97, 1.21).
Increases in waist circumference and weight during midlife do not appear to be associated with the risk of colorectal cancer.
关于中年时期体重或体重指数变化与结直肠癌风险之间关联的研究结果并不一致，且迄今为止仅有一项研究报告了腰围变化（一种中心性肥胖的衡量指标）与结直肠癌风险之间的关联。
我们调查了从基线期（1990 - 1994年）到第2阶段（2003 - 2007年）直接测量的腰围和体重变化与结直肠癌风险之间的关联。以年龄为时间度量，从第2阶段开始随访，采用Cox回归，并对从因果模型中选择的协变量进行调整，以估计腰围和体重变化相对于结直肠癌风险的风险比（HR）和95%置信区间（CI）。
在对20605名参与者平均9年的随访期间，共诊断出373例结直肠癌病例。腰围和体重的增加与结直肠癌风险无关（腰围每增加5厘米的HR = 1.02；95% CI：0.95，1.10；体重每增加5千克的HR = 0.93；0.85，1.02）。对于基线腰围小于特定性别平均值的个体，第2阶段腰围增加5厘米与结直肠癌风险略有增加相关（HR = 1.08；0.97，1.21）。
中年时期腰围和体重的增加似乎与结直肠癌风险无关。
