Effects of alcohol consumption on the prevalence and incidence of non-alcoholic fatty liver disease: A systematic review and meta-analysis

Background and aims Nonalcoholic fatty liver disease (NAFLD) is one of the most prevalent diseases worldwide, with its prevalence and incidence continually increasing. However, the impact of alcohol consumption on the development and progression of hepatic steatosis has not been systematically investigated. Our aim was to estimate the impact of alcohol consumption on the development and progression of NAFLD. Methods The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standards were followed. We conducted a search of Web of Science, PubMed, Embase, and the Cochrane Library without language restrictions, covering the period from inception to December 31, 2023. Abstract screening, full-text review, and data extraction were performed in duplicate. Results We identified 16 articles that reported adjusted data (Japan = 7, other countries = 9). Random-effects categorical meta-analyses were conducted to compare alcohol consumption levels (< 20 g/day for women and < 30 g/day for men) with those of non-drinkers. A total of 299,955 participants were included, with 63,693 cases of NAFLD. Overall, there was no significant difference in the prevalence of NAFLD between non-drinkers and light drinkers (RR = 0.99, 95% CI, 0.85–1.15). In subgroup analyses, no differences were observed between the Japan cohort (RR = 1.01, 95% CI, 0.81–1.25) and the participants from other countries (RR = 0.96, 95% CI, 0.76–1.21). Gender-specific subgroup analyses indicated that light drinking was associated with a reduced prevalence of NAFLD in men (RR = 0.82, 95% CI, 0.79–0.85), while no significant association was found in women (RR = 0.90, 95% CI, 0.60–1.36). Regarding incidence, non-drinkers were consistently associated with a substantially lower incidence of NAFLD compared to light drinkers (RR = 1.18, 95% CI, 1.08–1.30). Conclusion This study summarizes the impact of alcohol consumption on the incidence and prevalence of NAFLD. In prevalence, light drinking in men was associated with a lower prevalence of NAFLD, whereas light drinking was associated with a higher incidence of NAFLD.