Lifestyle factors and colorectal cancer risk (1): systematic review and meta-analysis of associations with body mass index.
Harriss, D J Atkinson, G George, K Cable, N Tim Reilly, Thomas Haboubi, Najib Zwahlen, Marcel Egger, Matthias Renehan, Andrew G
Harriss, D J
Atkinson, G
George, K
Cable, N Tim
Reilly, Thomas
Haboubi, Najib
Zwahlen, Marcel
Egger, Matthias
Renehan, Andrew G
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Abstract
OBJECTIVE: Excess body weight, defined by body mass index (BMI), may increase the risk of colorectal cancer. As a prerequisite to the determination of lifestyle attributable risks, we undertook a systematic review and meta-analysis of prospective observational studies to quantify colorectal cancer risk associated with increased BMI and explore for differences by gender, sub-site and study characteristics. METHOD: We searched MEDLINE and EMBASE (to December 2007), and other sources, selecting reports based on strict inclusion criteria. Random-effects meta-analyses and meta-regressions of study-specific incremental estimates were performed to determine the risk ratio (RR) and 95% confidence intervals (CIs) associated with a 5 kg/m(2) increase in BMI. RESULTS: We analysed 29 datasets from 28 articles, including 67,361 incident cases. Higher BMI was associated with colon (RR 1.24, 95% CIs: 1.20-1.28) and rectal (1.09, 1.05-1.14) cancers in men, and with colon cancer (1.09, 1.04-1.12) in women. Associations were stronger in men than in women for colon (P < 0.001) and rectal (P = 0.005) cancers. Associations were generally consistent across geographic populations. Study characteristics and adjustments accounted for only moderate variations of associations. CONCLUSION: Increasing BMI is associated with a modest increased risk of developing colon and rectal cancers, but this modest risk may translate to large attributable proportions in high-prevalence obese populations. Inter-gender differences point to potentially important mechanistic differences, which merit further research.
Description
Date
2009-07
Publisher
Collections
Keywords
Colonic Cancer
Colorectal Cancer
Colorectal Cancer
Type
Article
Citation
Lifestyle factors and colorectal cancer risk (1): systematic review and meta-analysis of associations with body mass index. 2009, 11 (6):547-63 Colorectal Dis