Alcohol consumption can reduce the risk of gallstone disease: A systematic review with a dose-response meta-analysis of case-control and cohort studies

Background/Aims: Gallstone disease (GSD) is a common gastrointestinal disorder. Clinical epidemiological studies revealed that alcohol consumption has a preventive effect on the development of GSD. This study aimed to evaluate the relative risks of drinking for GSD development and investigate the dose-response relationships. Methods: A systematic search of the MEDLINE, EMBASE, and Cochrane Library databases for studies published up to 2018 was performed. All studies that satisfied the following eligibility criteria were included: patients with GSD with or without cholecystitis; and cohort or case-control studies investigating the association between alcohol consumption and GSD development. Results: Sixteen case-control studies including 24,401 gallstone cases and 76,185 controls, and eight cohort studies with 14,693 GSD cases among 2,432,471 person-years were enrolled. Alcohol consumption presented a decreased overall risk of GSD (pooled relative ratio [RR], 0.84; 95% confidence interval [CI], 0.79 to 0.89; p=0.02). Subgroup analyses according to drinking levels indicated a gradual risk reduction for GSD compared to nondrinkers (light: RR, 0.96; 95% CI, 0.94 to 0.99; p=0.75; moderate: RR, 0.80; 95% CI, 0.75 to 0.85; p=0.27; high: RR, 0.66; 95% CI, 0.56 to 0.79; p<0.01). A nonlinear risk reduction was observed in a dose-response meta-analysis of all the studies (n=14, p<0.01 for nonlinearity). Conclusions: In this systematic review with meta-analysis, alcohol consumption could decrease the risk of GSD, and the dose-response analysis revealed a dose-dependent linear risk reduction and a weakened linear trend between alcohol consumption levels less than and greater than 28 g/day. (Gut Liver 2019;13:114-131).