Background: To provide a quantitative assessment of the association between body mass index (BMI) and the risk of gastric cancer, we summarized the evidence from prospective studies.
Methods: Eligible studies published up to November 30, 2012, were retrieved via computer searches of MEDLINE and EMBASE as well as manual review of references. Summary relative risks (SRR) with their corresponding 95% confidence intervals (CI) were calculated using a random-effects model.
Results: A total of 24 prospective studies of BMI and gastric cancer risk with 41,791 cases were included in our analysis. Overall, both overweight (BMI, 25-30 kg/m(2)) and obesity (BMI, ≥30 kg/m(2)) were not associated with risk of total gastric cancer (overweight: SRR, 1.01; 95% CI, 0.96-1.07; obesity: SRR, 1.06; 95% CI, 0.99-1.12). Furthermore, we found increased BMI was positively associated with the risk of gastric cardia cancer (GCC; SRR = 1.21 for overweight and 1.82 for obesity), but not with gastric non-cardia cancer (GNCC; SRR = 0.93 for overweight and SRR = 1.00 for obesity). Similar results were observed in a linear dose-response analysis.
Conclusion: On the basis of meta-analysis of prospective studies, we find high BMI is positively associated with the risk of GCCs but not with GNCCs.
Impact: (i) On the basis of more definite and quantitative evidence than previously available, we found that increasing BMI was not a clear risk factor for total gastric cancer. (ii) Increased BMI was positively associated with risk of GCC but not with GNCCs.