Abdominal obesity increases the risk of reflux esophagitis: a systematic review and meta-analysis

Background and objectives The association between abdominal obesity and reflux esophagitis (RE) has been extensively evaluated, but the current findings are mixed and more convincing epidemiological evidence urgently needs to be established. To thoroughly explore this relationship, we summarized the latest studies, performed an updated meta-analysis, and examined the dose-response relationship. Methods We performed a systematic search of PubMed, Web of Science, and Embase up to 28 March 2021, using prespecified terms to identify studies investigating the association between abdominal obesity and RE. Odds ratios (ORs) with 95% confidence intervals (CIs), mean differences (MDs) or standardized mean differences (SMDs) with 95% CIs were taken as effect-size estimates. Results Forty-two observational studies, including 11 cohort studies, were meta-analyzed. Overall, a statistically significant association was observed between abdominal obesity and RE, by both the pooled OR (adjusted OR = 1.51, 95% CI: 1.37-1.66, p < .001) and the pooled SMD (SMD = 0.36, 95% CI: 0.30-0.42, p < .001). Moreover, this significant relationship persisted with subgroup stratification. In subgroup analyses, we found that study design, abdominal obesity measurement, adjustment for covariates and sex were possible sources of between-study heterogeneity. For the dose-response analyses, the risk of RE increased with the degree of abdominal obesity, and the increasing trend accelerated when waist circumference (WC) reached 87.0 cm. Conclusion This meta-analysis indicated a significant association between abdominal obesity and RE, and the risk of RE increased with abdominal obesity especially when the WC was over 87.0 cm.