Improved body composition is associated with reduced steatosis in non-alcoholic fatty liver disease, a systematic review and meta-analysis of longitudinal studies

Background: Based on cross-sectional studies, there is a link between body composition parameters and steatosis in non-alcoholic fatty liver disease (NAFLD). However, whether long-term changes in different body composition parameters will result in NAFLD resolution is unclear. Therefore, we aimed to summarize the literature on longitudinal studies evaluating the association between NAFLD resolution and body composition change.

Methods: Based on the recommendations of the Cochrane Handbook, we performed a systematic search on September 26th, 2021, in four databases: Embase, MEDLINE (via PubMed), and Cochrane Central Register of Controlled Trials (CENTRAL). Eligible studies reported on patients with NAFLD (liver fat >5%) and examined the correlation between body composition improvement and a decrease in steatosis. We did not have pre-defined body composition or steatosis measurement criteria. Next, we calculated pooled correlation coefficient (r) with a 95% confidence interval (CI).

Results: We identified 15 eligible studies, of which 5 five studies were included in our quantitative synthesis. Based on two studies with 85 patients, we found a pooled correlation coefficient of r=0.49 (CI: 0.22-0.69, Spearman’s correlation) between the change of visceral adipose tissue and liver steatosis. Similarly, based on three studies with 175 patients, the correlation was r=0.33 (CI: 0.19-0.46, Pearson’s correlation). On the other hand, based on two studies with 163 patients, the correlation between subcutaneous adipose tissue change and liver steatosis change was r=0.42 (CI: 0.29-0.54, Pearson’s correlation).

Conclusion: Based on the included studies, body composition improvement is associated with a decrease in liver fat content in NAFLD.