Potential involvement of adiponectin in obesity-associated erosive esophagitis

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.

Sex differences in risk factors for future onset of reflux esophagitis

Reflux esophagitis is known to be more prevalent in males, and previous studies have suggested sex differences in its risk factors. However, little is known about sex differences in the time-course of risk factors before reflux esophagitis onset. Thus, we conducted a retrospective longitudinal study using health checkup records. From the records of 230,056 individuals obtained from nine institutes in Japan, we selected 1,558 male reflux esophagitis cases, 3,116 male controls, 508 female reflux esophagitis cases, and 1,016 female controls were selected. We compared time-courses of risk factors between the case and control groups and identified abdominal circumference (AC), diastolic blood pressure, alanine transaminase (ALT), and current smoking in males and body mass index (BMI) in females as sex-specific risk factors. We also found that AC and ALT in males and BMI in females were significantly different between the reflux esophagitis case and control groups during the five years before reflux esophagitis onset. Our results suggest that visceral fat-type obesity and fatty liver in males and higher BMI in females are more frequently observed in reflux esophagitis cases several years before reflux esophagitis onset, and that proactive intervention to lifestyle can help prevent reflux esophagitis in both males and females.