Meta-Analysis
Copyright ©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Mar 14, 2017; 23(10): 1909-1919
Published online Mar 14, 2017. doi: 10.3748/wjg.v23.i10.1909
Markers of systemic inflammation and colorectal adenoma risk: Meta-analysis of observational studies
Justyna Godos, Antonio Biondi, Fabio Galvano, Francesco Basile, Salvatore Sciacca, Edward L Giovannucci, Giuseppe Grosso
Justyna Godos, Salvatore Sciacca, Giuseppe Grosso, Integrated Cancer Registry of Catania-Messina-Siracusa-Enna, Azienda Ospedaliero Universitaria Policlinico Vittorio Emanuele, 95123 Catania, Italy
Antonio Biondi, Francesco Basile, Department of General Surgery, Section of General Surgery and Oncology, University of Catania, 95123 Catania, Italy
Fabio Galvano, Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
Edward L Giovannucci, Department of Epidemiology, Harvard TH Chan School of Public Health, Boston, MA 02115, United States
Edward L Giovannucci, Department of Nutrition, Harvard TH Chan School of Public Health, Boston, MA 02115, United States
Edward L Giovannucci, Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA 02115, United States
Author contributions: Godos J performed the search, the analysis, and wrote the manuscript; Biondi A, Galvano F, Basile F and Sciacca S provided critical revision; Giovannucci EL and Grosso G designed the study, and provided insights on methodology, data interpretation and manuscript drafting (equal contribution).
Conflict-of-interest statement: The authors deny any conflict of interest.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Giuseppe Grosso, MD, PhD, Integrated Cancer Registry of Catania-Messina-Siracusa-Enna, Azienda Ospedaliero Universitaria Policlinico Vittorio Emanuele, 95123 Catania, Italy. giuseppe.grosso@studium.unict.it
Telephone: +39-95-3782110 Fax: +39-95-3782110
Received: December 11, 2016
Peer-review started: December 12, 2016
First decision: January 10, 2017
Revised: January 20, 2017
Accepted: February 16, 2017
Article in press: February 17, 2017
Published online: March 14, 2017
Abstract
AIM

To perform a meta-analysis of observational studies on inflammatory markers levels and occurrence of colorectal adenoma.

METHODS

PubMed and EMBASE databases were searched until March 2016 for the articles reporting on the circulating levels of inflammatory markers, including: C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) and risk of colorectal adenoma. Random-effects models were used to calculate summary odds ratios (ORs) with 95%CIs for the highest vs lowest category of exposure. Heterogeneity was assessed by using the Q test and I2 statistic. Subgroup analyses were also performed to test for potential source of heterogeneity.

RESULTS

A total of 14 case-control studies were included. Ten studies on CRP including a total of 3350 cases and 4168 controls showed non-significant summary (OR = 1.23, 95%CI: 0.98-1.54; I2 = 54%, Pheterogeneity = 0.01) in the general analysis, but significant increased odds when considering only advanced adenoma (OR = 1.59, 95%CI: 1.09-2.32; I2 = 44%, Pheterogeneity = 0.15). Subgroup and stratified analyses revealed a potential influence of smoking status and aspirin use on the association between CRP levels and colorectal adenoma. Five studies examined the association between circulating levels of TNF-α and colorectal adenoma risk, including a total of 1,568 cases and 2,832 controls. The summary OR for the highest vs the lowest category of exposure was 1.00 (95%CI: 0.77-1.29). The relationship between circulating IL-6 levels and colorectal adenoma risk was investigated in 7 studies including a total of 1936 cases and 3611 controls. The summary OR for the highest vs the lowest category of exposure was 1.19 (95%CI: 0.92-1.55).

CONCLUSION

Summary of current evidence suggests a positive association of CRP levels and advanced colorectal adenoma risk. The role of potential confounding factors should be further evaluated.

Keywords: Inflammatory markers, Meta-analysis, Colorectal adenoma, C-reactive protein, Tumor necrosis factor-alpha, Interleukin-6

Core tip: The present study investigated the association between inflammatory markers and risk of colorectal adenoma. Ten studies on C-reactive protein (CRP) showed non-significant summary odds ratios in the general analysis. However, CRP was significantly correlated with increased risk of advanced adenoma. Subgroup and stratified analyses revealed a potential influence of smoking status and aspirin use on the association between CRP levels and colorectal adenoma risk. The results of the study may have practical value for clinicians screening for colorectal cancer.