Adult weight gain and colorectal adenomas-a systematic review and meta-analysis.
BACKGROUND
Colorectal adenomas are known as precursors for the majority of colorectal carcinomas. While weight gain during adulthood has been identified as a risk factor for colorectal cancer, the association is less clear for colorectal adenomas. We conducted a systematic review and meta-analysis to quantify the evidence on this association.


METHODS
We searched Medline up to September 2016 to identify observational (prospective, cross-sectional and retrospective) studies on weight gain during adulthood and colorectal adenoma occurrence and recurrence. We conducted meta-analysis on high weight gain versus stable weight, linear and non-linear dose-response meta-analyses to analyze the association. Summary odds ratios (OR) and 95% confidence intervals (95% CI) were estimated using a random effects model.


RESULTS
For colorectal adenoma occurrence, the summary OR was 1.39 (95% CI: 1.17-1.65; I2: 43%, N = 9 studies, cases = 5507) comparing high (midpoint: 17.4 kg) versus stable weight gain during adulthood and with each 5 kg weight gain the odds increased by 7% (2%-11%; I2: 65%, N = 7 studies). Although there was indication of non-linearity (Pnon-linearity < 0.001) there was an increased odds of colorectal adenoma throughout the whole range of weight gain. Three studies were identified investigating the association between weight gain and colorectal adenoma recurrence and data were limited to draw firm conclusions.


CONCLUSIONS
Even a small amount of adult weight gain was related to a higher odds of colorectal adenoma occurrence. Our findings add to the benefits of weight control in adulthood regarding colorectal adenoma occurrence, which might be relevant for early prevention of colorectal cancer.
Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK.|Junior Research Group Systematic Reviews, Institute for Biometrics and Epidemiology, German Diabetes Center, Düsseldorf.
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S
Schlesinger
Nutrition, Immunity and Metabolism Start-up Lab, Department of Epidemiology, German Institute of Human Nutrition Potsdam-Rehbrücke, Nuthetal, Germany.
K
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Aleksandrova
Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK.
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L
Abar
Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK.
A R
AR
Vieria
Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK.
S
S
Vingeliene
Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK.
E
E
Polemiti
Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK.
C A T
CAT
Stevens
Division of Epidemiology and Biostatistics, School of Medicine, University of Leeds, Leeds, UK.
D C
DC
Greenwood
Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK.
D S M
DSM
Chan
Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK.|Bjørknes University College, Oslo, Norway.
D
D
Aune
Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK.
T
T
Norat
D000236:Adenoma / Q000503:physiopathology*; D000328:Adult; D015179:Colorectal Neoplasms / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015430:Weight Gain
body weight change; body weight gain; colorectal adenomas; meta-analysis; observational studies; polyps