Physical activity intervention for non-diabetic patients with non-alcoholic fatty liver disease: a meta-analysis of randomized controlled trials

Abstract

Background: Non-alcoholic fatty liver disease (NAFLD) is currently the most common cause of chronic liver disease nowadays. Changes in diet and lifestyle have led to a dramatic increase in the prevalence of NAFLD around the world. This meta-analysis is to investigate the efficacy of physical activity intervention on liver-specific endpoints in the population with NAFLD, including hepatic enzyme, serum lipid, glucose metabolism and intra-hepatic lipid. Methods: PubMed and China National Knowledge Infrastructure (CNKI) databases were searched for randomized clinical trials of physical activity intervention on NAFLD patients through April 20th, 2019. Effect sizes were reported as standardized mean difference (SMD) and 95% confidence intervals (CI). Quality of included studies was assessed according to the Cochrane risk of bias tool. Meta-analyses were conducted using random-effect or fixed-effect models depending on the significance of heterogeneity. Subgroup analyses according to types and duration of physical activity were conducted to investigate clinical variability. Results: Nine studies with a cumulative total of 951 participants met selection criteria. Physical activity was found associated with small reductions in hepatic enzyme parameters: ALT (SMD-0.17, 95% CI:-0.30 to − 0.05), AST (SMD-0.25, 95% CI: − 0.38, − 0.13) and GGT (SMD-0.22, 95% CI: − 0.36, − 0.08). Significant small improvements were also found in serum lipid parameters including TC (SMD = − 0.22, 95% CI: − 0.34, − 0.09), TG (SMD = − 0.18, 95% CI: − 0.31 to − 0.06) and LDL-C (SMD = − 0.26, 95% CI: − 0.39 to − 0.13). Significant improvement was also found in intrahepatic lipid content (SMD = − 0.21, 95% CI: − 0.36 to − 0.06) There was no difference between physical intervention group and control group in HDL and three glucose metabolism parameters. Subgroup analysis suggested both aerobic exercise alone and resistance exercise alone can improve most liver function and longer period of exercise generally had better improvement effect.

Effect of Different Exercise Methods on Non-Alcoholic Fatty Liver Disease: A Meta-Analysis and Meta-Regression

“…As far as we know, this study is the first to analyze the effects of different exercise modes on blood biochemical indexes (TG, TC, LDL, and HDL), liver function related enzymes (ALT, AST, and GGT), and BMI in patients with NAFLD. This meta-analysis showed that aerobic exercise and resistance exercise can significantly improve TG and AST in patients with NAFLD, which is consistent with a recent study [ 30 ]. Aerobic exercise and HIIT can significantly reduce ALT in patients with NAFLD.…”

Peroxisome Proliferator-Activated Receptors and Their Novel Ligands as Candidates for the Treatment of Non-Alcoholic Fatty Liver Disease

“…Interestingly, although combining an exercise program with dietary interventions augments the reduction in hepatic fat content, exercise only is also effective in reducing hepatic lipid content in NAFLD patients [136,146]. As most of the studies have been performed with diabetic and/or obese NAFLD patients, the beneficial effect of exercise still needs confirmation in large-scale prospective studies, as a recent meta-analysis showed that physical activity only slightly reduces liver fat content in non-diabetic NAFLD patients [147]. Interestingly, starting to exercise has been independently associated with NAFLD remission only in men, suggesting a sex-specific hepatic response to exercise [148].…”

Effects of Dietary and Lifestyle Interventions on Liver, Clinical and Metabolic Parameters in Children and Adolescents with Non-Alcoholic Fatty Liver Disease: A Systematic Review

“…Meta-analyses in adult population with NAFLD clearly showed that exercise alone has a large effect on IHTG levels, which remains significant even in the absence of weight loss [56,57]. Both aerobic [58] and resistance exercise [59], compared to usual care or their combination [43], are shown to improve IHTG or other glucose metabolic indices, such as HOMA-IR and HbA1C, while no clear superiority of aerobic exercise over resistance exercise exists [60,61].…”