Sex-specific differences in ectopic fat and metabolic characteristics of paediatric nonalcoholic fatty liver disease

Background/ObjectivesSex-specific differences in obesity-related metabolic characteristics of non-alcoholic fatty liver disease (NAFLD) have rarely been explored, particularly in children with biopsy-verified NAFLD. The influence of sex hormones on ectopic fat disposition may cause inter-sex differences in various metabolic factors. This study aimed to assess the sex-based differences in ectopic fat and metabolic characteristics in children with NAFLD.Subject/MethodsWe enrolled 63 children with biopsy-verified NAFLD (48 boys; mean age, 12.9 +/- 3.2 years; mean body mass index z-score [BMI-z], 2.49 +/- 1.21). Ectopic fat in the liver and pancreas was quantified based on magnetic resonance imaging within 2 days of the liver biopsy. Laboratory tests, body composition, blood pressure, and anthropometric measurements were also assessed.ResultsSex-based differences were neither observed in age, BMI-z, or total body fat percentage nor in the proportions of obesity, abdominal obesity, diabetes, dyslipidaemia, hypertension, or metabolic syndrome. Furthermore, liver enzyme levels, lipid profiles, and pancreatic fat did not differ between the sexes. However, boys had significantly higher fasting insulin (median 133.2 vs. 97.8 pmol/L; p = 0.039), fasting plasma glucose (median 5.30 vs. 4.83 mmol/L; p = 0.013), homeostasis model assessment of insulin resistance (median 5.4 vs. 3.6; p = 0.025), serum uric acid (404.1 +/- 101.2 vs. 322.4 +/- 87.1 mu mol/L; p = 0.009), and liver fat (median 26.3% vs. 16.3%; p = 0.014).ConclusionsMale-predominant hepatic steatosis and insulin resistance caused by sex-specific ectopic fat accumulation may contribute to higher uric acid levels in boys than in girls with NAFLD.