Association between fatty liver disease markers and physical activity and sedentary time in children and adolescents with obesity

Abstract Purpose: To compare patterns of sedentary (SED) time (more sedentary, SED+ vs less sedentary, SED-), moderate to vigorous physical activity (MVPA) time (more active, MVPA+ vs less active, MVPA-) and combinations of behaviors (SED-/MVPA+, SED-/MVPA-, SED+/MVPA+, SED+/MVPA-) regarding nonalcoholic fatty liver diseases (NAFLD) markers. Methods: This cross-sectional study included 134 subjects (13.4±2.2yrs, body mass index (BMI) 98.9±0.7 percentile, 48.5% females) who underwent 24h/7day accelerometry, anthropometric and biochemical markers (alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (GGT), AST/ALT and Fatty Liver Index (FLI)). A subgroup of 39 patients underwent magnetic resonance imaging-liver fat content (MRI-LFC).Results: Hepatic health was better in SED- [lower ALT, GGT and MRI-LFC (p<0.05), higher AST/ALT (p<0.01)] vs SED+ and in MVPA+ [lower ALT (p<0.05) and FLI (p=0.001), higher AST/ALT (p<0.01)] vs MVPA- groups after adjustment for age, gender and Tanner stages. SED-/MVPA+ group had the best hepatic health. SED-/MVPA- group had lower ALT and GGT and higher AST/ALT (p<0.05) in comparison with SED+/MVPA+ group independently of BMI. SED time was positively associated with biochemical (high ALT, low AST/ALT ratio) and imaging (high MRI-LFC) markers independently of MVPA. MVPA time was associated with biochemical markers (low ALT, FLI, high AST/ALT) but these associations were no longer significant after adjustment for SED time, except for FLI (p<0.001). Conclusions: Lower SED time is associated with better hepatic health independently of MVPA. Reducing SED time might be a first step in the management of pediatric obesity NAFLD when increasing MVPA is not possible.