Body-mass index and colorectal neoplasia according to gender and ethnicity: a systematic review and meta-analysis
Invited conference paper presented and published in conference proceedings

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AbstractImportance: The precise magnitude of the association between Body mass index (BMI) and colorectal adenoma (CRA) remains unknown, and whether there exist differences in this association in subjects with different characteristics is uncertain.
Objective: to evaluate the association between BMI and CRA, and examine if this association is different according to study design, gender and ethnicity.
Data Sources: Ovid Medline, EMBASE and the PsychINFO from their inception to September 2016.
Data Extraction and Synthesis: All high quality observational studies that examined the association between physician-measured BMI and colonoscopy-diagnosed CRA were included. Data were independently extracted by two reviewers and in cases of disagreement, and consensus was made via referral to a third reviewer.
Main Outcomes and Measures: We evaluated the pooled odds ratio between BMI and CRA via a random effects model. The Cochran’s Q statistic and I2 analyses were used to assess between-study heterogeneity. Subgroup analysis was performed according to study design, gender and ethnicity.
Results: A total of 17 studies (55,083 subjects) were included for analysis (Figure 1). When compared with subjects having BMI<25, the prevalence of CRA was significantly higher in subjects with BMI 25-30 (summary odds ratio [SOR]=1.44, 95% C.I. 1.30-1.61) and BMI>30 (SOR=1.42, 095% C.I. 1.24, 1.63; both p<0.001) (Figure 2). These pooled risks had low to moderate levels of heterogeneity among studies (I2=43.0% and 18.5%, pheterogeneity =0.10 and 0.19, respectively). The publication bias was insignificant (Egger’s regression test, p=0.584). Subgroup analysis showed no difference in the pooled risk according to study design. The magnitude of association was significantly higher in female (SOR=1.43, 95% C.I. 1.30, 1.58; I2=9.4%, pheterogeneity=0.225) than male subjects (SOR=1.16, 95% C.I. 1.07, 1.24; I2=0%, pheterogeneity=0.374). The association was also different among different ethnic groups (SOR=1.72, 95% C.I. 1.44, 0.88 in whites, Asians and Africans, respectively), and was absent in subjects of African descent (SOR=0.88, 95% C.I. 0.61, 1.29, p=0.516; I2=0%, pheterogeneity=0.680). Potential covariates that might affect heterogeneity of the odds ratios, including age, gender, year of publication, smoking, alcohol drinking, use of aspirin or non-steroidal anti-inflammatory agents, family history of CRC, and presence of diabetes or hypertension were examined for all studies. None of these covariates were found to be significant by both univariate and multivariate meta-regression analysis.
Conclusions and Relevance: These findings based on high quality studies showed that the risk conferred by BMI for CRA was significantly higher than that reported previously. The association is higher in white and female individuals, and this bears implications in risk estimation of CRA.
Acceptance Date15/02/2017
All Author(s) ListMartin C Wong, C.H. Chan, Yanhong Wang, Jason L. Huang, Wilson L Cheung, Miaoyin Liang, Yuan Fang, Chun Pong Yu, Johnny Y. Jiang, Harry Hao-Xiang Wang, Justin C. Wu, Francis K. Chan
Name of ConferenceDigestive Disease Week 2017
Start Date of Conference06/05/2017
End Date of Conference09/05/2017
Place of ConferenceChicago
Country/Region of ConferenceUnited States of America
Proceedings TitleGastroenterology
Volume Number152
Issue Number5
Place of PublicationUS
Pages21 - 22
LanguagesEnglish-United States
Keywordscolorectal cancer, screening, body mass index, obesity

Last updated on 2021-17-06 at 00:42