Relationship between obesity and development of erosive reflux disease: A mediation analysis of the role of cardiometabolic risk factors

This study aimed to evaluate whether the relationship between obesity and erosive reflux disease (ERD) is mediated by cardiometabolic risk factors. This cohort study included subjects who underwent repeated endoscopy. To assess whether the association between body mass index (BMI) and ERD development was mediated by cardiometabolic parameters, multivariate Cox proportional hazard models were fitted for mediation analysis. Of 15,154 subjects with negative index endoscopy findings during health check-up, 11,686 subjects who underwent repeated endoscopy were included. During follow-up, 1,367 incident ERD events (11.7%) were observed. Without mediation effect, the multivariate adjusted hazard ratio of BMI was 1.21 (95% CI, 1.03-1.42) in overweight and 1.39 (95% CI, 1.19-1.62) in obese individuals compared to normal weight individuals. When the metabolic syndrome was included as a mediator, the hazard ratio became 1.19 (95% CI, 1.00-1.40) in overweight and 1.29 (95% CI, 1.10-1.52) in obese individuals. Both systolic blood pressure and triglyceride level were found to fully mediate the effect of BMI on ERD. Fasting glucose level was a partial mediator. The estimated percentage of total effect mediated by cardiometabolic risk factors was 35.4%. Cardiometabolic parameters partially or fully mediate the association between overweight and obesity and incident ERD.