Obesity is an independent risk factor for non-alcoholic fatty liver disease: evidence from a meta-analysis of 21 cohort studies

Abstract

Background: The association between obesity and nonalcoholic fatty liver disease (NAFLD) has not been fully quantified, and the magnitude of NAFLD risk associated with obesity is still unclear. A meta-analysis of cohort studies was performed to elucidate the NAFLD risk associated with obesity.

Methods: Pubmed, Web of Science and Embase were searched for cohort studies assessing NAFLD risk associated with obesity or increased body mass index (BMI). Relative risks (RRs) with 95% confidence intervals (95%CIs) were pooled using random-effects model of meta-analysis.

Results: Twenty-one cohort studies including 13 prospective studies and 8 retrospective studies were finally included. There were a total of 381,655 participants in the meta-analysis. Compared with normal weight, obesity independently led to a 3.5-fold increased risk of developing NAFLD (RR = 3.53, 95%CI 2.48 to 5.03, P < 0.001). Meta-analysis also suggested an obvious dose-dependent relationship between BMI and NAFLD risk (per 1-unit increment in BMI: RR = 1.20, 95%CI 1.14 to 1.26, P < 0.001). Subgroup analyses further identified the robustness of the association above. No obvious risk of publication bias was observed.

Conclusion: Obese individuals have a 3.5-fold increased risk of developing NAFLD, and there is an obvious dose-dependent relationship between BMI and NAFLD risk. © 2016 World Obesity.

Keywords: nonalcoholic fatty liver disease; obesity; risk factor.