Body Mass Index Category as a Risk Factor for Colorectal... : Official journal of the American College of Gastroenterology | ACG (original) (raw)

REVIEW: CLINICAL AND SYSTEMATIC REVIEWS

Body Mass Index Category as a Risk Factor for Colorectal Adenomas: A Systematic Review and Meta-Analysis

Okabayashi, Koji MD1, 2; Ashrafian, Hutan MBBS, MRCS1; Hasegawa, Hirotoshi MD, FRCS2; Yoo, Jae-Hoon MD3; Patel, Vanash M MBBS, MRCS1; Harling, Leanne MBBS, MRCS1; Rowland, Simon P BSc (Hons), MBBS1; Ali, Mariam BSc (Hons)1; Kitagawa, Yuko MD, PhD2; Darzi, Ara PC, KBE, MD, FRCSI, FRCS, FMedSci1; Athanasiou, Thanos MD, PhD, FRCS, FETCS1

1 Department of Surgery and Cancer, Imperial College London, London, UK

2 Department of Surgery, Keio University, School of Medicine, Tokyo, Japan

3 Department of Surgery, National Hospital Organization Saitama National Hospital, Saitama, Japan

Correspondence: Thanos Athanasiou, Department of Surgery and Cancer, Imperial College London, 10th Floor QEQM-Building, Praed Street, London W2 1NY, UK. E-mail: [email protected]

SUPPLEMENTARY MATERIAL accompanies this paper at https://links.lww.com/AJG/A511

Received 3 February 2012; accepted 23 April 2012

published online 26 June 2012

Abstract

OBJECTIVES:

The association between increasing body weight and colorectal adenoma prevalence has been suggested to follow a similar pattern to excess weight and colorectal cancer, although the magnitude of this relationship has not been validated. The objective of this study was to quantify the association and dose–response relationship between body mass index (BMI) and colorectal adenoma prevalence in clinical trials.

METHODS:

We systematically reviewed 23 studies (168,201 participants), which compared the prevalence of colorectal adenomas according to World Health Organization BMI categories. We assessed the effects of each BMI category on colorectal adenomas where odds ratio (OR) was used as a surrogate for effect size, and applied multivariate meta-analysis as a method of sensitivity analysis to evaluate the robustness of our findings and to analyze adenoma prevalence by multiple BMI categories simultaneously to assess for a dose–response relationship. Heterogeneity and publication bias were assessed.

RESULTS:

Subjects with a BMI of ≥25 had a significantly higher prevalence of colorectal adenomas (OR=1.24 (95% confidence interval (CI): 1.16–1.33), P <0.01) when compared with those with BMI<25. Multivariate meta-analysis also confirmed a positive association between higher BMI categories and the prevalence of colorectal adenoma (BMI: 25–30 vs. BMI<25; OR=1.21 (95% CI: 1.07–1.38), P <0.01; BMI≥30 vs. BMI<25; OR=1.32 (95% CI: 1.18–1.48), P <0.01) and revealed a dose–response relationship.

CONCLUSIONS:

The positive association between obesity and colorectal adenoma prevalence demonstrates an underlying dose–response relationship according to BMI. Colorectal centers may benefit from the timely screening of obese patients for colorectal adenomas in addition to clarifying the biological role of adiposity on colorectal tumor initiation and progression.