Body mass index and risk of gastric cancer: a meta-analysis.

OBJECTIVE Overweight and obesity, indicated as increased body mass index, are associated with the risk of some cancers. We carried out a meta-analysis on published cohort and case-control studies to assess the strength of association between body mass index and gastric cancer. METHODS Relevant studies were identified through PubMed, Web of Science and Medline electronic databases. Adjusted relative risks (odds ratios) with 95% confidence interval were used to assess the strength of association between body mass index and gastric cancer. RESULTS Sixteen eligible studies were included in this meta-analysis. Overall, obesity (body mass index ≥ 30 kg/m(2)) was associated with an increased risk of gastric cancer (odds ratio = 1.13, 95% confidence interval = 1.03-1.24) compared with normal weight (body mass index = 18.5 to <25 kg/m(2)), while overweight (body mass index = 18.5 to <30 kg/m(2)) showed no association (odds ratio = 1.04, 95% confidence interval = 0.96-1.12). Specifically, a stratified analysis showed there were associations between obesity and the increased risk of gastric cancer for males (odds ratio = 1.27, 95% confidence interval = 1.09-1.48), non-Asians (odds ratio = 1.14, 95% confidence interval = 1.02-1.28) and both cohort studies (odds ratio = 1.10, 95% confidence interval = 1.00-1.22) and case-control studies (odds ratio = 1.29, 95% confidence interval = 1.03-1.60). Both overweight (odds ratio = 1.22, 95% confidence interval = 1.05-1.42) and obesity (odds ratio = 1.61, 95% confidence interval = 1.15-2.24) were associated with the increased risk of gastric cardia cancer. CONCLUSIONS The results indicated that obesity was associated with the risk of gastric cancer, especially for males and among non-Asians. Both overweight and obesity were associated with the risk of gastric cardia cancer.