Meta-Analysis
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World J Gastroenterol. Feb 14, 2013; 19(6): 936-945
Published online Feb 14, 2013. doi: 10.3748/wjg.v19.i6.936
Pre-existing diabetes mellitus increases the risk of gastric cancer: A meta-analysis
Jae Moon Yoon, Ki Young Son, Chun Sick Eom, Daniel Durrance, Sang Min Park
Jae Moon Yoon, Sang Min Park, Department of Family Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul 110-744, South Korea
Ki Young Son, Center for Health Promotion, Seoul National University Hospital, Seoul 110-744, South Korea
Chun Sick Eom, Department of Family Medicine, Hallym University, Chuncheon Sacred Heart Hospital, ChunCheon 200-704, South Korea
Daniel Durrance, Family Medicine, Graduate School of Korea University College of Medicine, Seoul 110-799, South Korea
Author contributions: Yoon JM and Son KY have contributed equally to this article; Yoon JM and Son KY designed study, analyzed data and wrote manuscript; Eom CS contributed discussion and wrote manuscript; Durrance D edited manuscript; Park SM designed study, contributed discussion and edited manuscript.
Supported by Grant from the Seoul National University Hospital Research Fund, No. 04-2011-0540
Correspondence to: Dr. Sang Min Park, Department of Family Medicine, Seoul National University Hospital, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 110-744, South Korea. sangmin.park.snuh@gmail.com
Telephone: +82-2-20723331 Fax: +82-2-7663276
Received: August 18, 2012
Revised: October 22, 2012
Accepted: October 30, 2012
Published online: February 14, 2013
Abstract

AIM: To systematically assess the association between diabetes and incidence of gastric cancer.

METHODS: We searched MedLine (PubMed), EMBASE, and the Cochrane Library without any limitations with respect to publication date or language, we also searched the references of qualifying articles. Case-control studies and cohort studies comparing the risk of gastric cancer between diabetic patients and control subjects were included. We excluded studies reporting only standardized incidence ratios without control groups and those that investigated only mortality but not incidence. Seventeen studies met our criteria, and the qualities of these studies were assessed using the Newcastle-Ottawa Quality Assessment Scale. We performed a meta-analysis of pre-existing diabetes and gastric cancer incidence using the DerSimonian-Laird method for random-effects. For subgroup analyses, we separated the studies by study type, region, sex and method to determine confounding factors and reliability. We also conducted subgroup analyses to examine the effects of smoking, Helicobacter pylori (H. pylori) infection, and cancer site. Publication bias was evaluated using Begg’s test.

RESULTS: A random-effects model meta-analysis showed an increased gastric cancer risk in diabetic patients [relative risk (RR) = 1.19; 95%CI: 1.08-1.31]. Subgroup analyses indicated that this result persisted in cohort studies (RR = 1.20; 95%CI: 1.08-1.34), in studies on populations of both Western (RR = 1.18; 95%CI: 1.03-1.36) and Eastern countries (RR = 1.19; 95%CI: 1.02-1.38), in a female subgroup (RR=1.24; 95%CI: 1.01-1.52), and in highly qualified studies (RR = 1.17; 95%CI: 1.05-1.31). Moreover, these results persisted when the analysis was confined to studies adjusted for well-known gastric cancer risk factors such as smoking (RR = 1.17; 95%CI: 1.01-1.34) and H. pylori infection (RR = 2.35; 95%CI: 1.24-4.46).

CONCLUSION: Pre-existing diabetes mellitus may increase the risk of gastric cancer by approximately 19%. This effect seems to be unrelated to geographical region.

Keywords: Disease association, Diabetes mellitus, Gastric cancer, Incidence, Risk, Meta-analysis