Increased liver echogenicity and liver enzymes are associated with extreme obesity, adolescent age and male gender: analysis from the German/Austrian/Swiss obesity registry APV

Abstract

Background: Childhood obesity is often associated with non-alcoholic fatty liver disease (NAFLD), the most common chronic liver disease in pediatrics.

Methods: This multi-center study analyzed liver echogenicity and liver enzymes in relation to obesity, age, gender and comorbidities. Data were collected using a standardized documentation software (APV) from 1.033 pediatric patients (age: 4-18 years, body mass index = BMI: 28-36 kg/m², 50% boys) with overweight (BMI >90th percentile), obesity (BMI >97th percentile) or extreme obesity (BMI > 99.5th percentile) and obesity related comorbidities, especially NAFLD from 26 centers of Germany, Austria and Switzerland. Liver enzymes aspartate aminotransferase (AST), alanine-aminotransferase (ALT) and gamma glutamyltransferase (gammaGT) were evaluated using 2 cut-off values a) > 25 U/L and b) > 50 U/L. Multiple logistic regression models were used for statistical analysis.

Results: In total, 44% of the patients showed increased liver echogenicity. Liver enzymes > 25 U/L were present in 64% and > 50 U/L in 17%. Increased liver echogenicity was associated with elevated liver enzymes (> 25 U/L: odds ratio (OR) = 1.4, 95% CI: 1.1-1.9, P < 0.02; > 50 U/L: OR = 3.5, 95% CI: 2.4-5.1, P < 0.0001). Extreme obesity, adolescence and male gender were associated with increased liver echogenicity (extreme obesity vs overweight OR = 3.5, 95% CI: 1.9-6.1, P < 0.0001; age > 14 years vs age < 9 years OR = 2.2, 95% CI: 1.4-3.5, P < 0.001; boys vs girls OR = 1.6, 95% CI: 1.2-2.0, P < 0.001) and elevated liver enzymes (extreme obesity vs overweight > 25 U/L: OR = 4.1, 95% CI: 2.4-6.9, P < 0.0001; > 50 U/L: OR = 18.5, 95% CI: 2.5-135, P < 0.0001; age > 14 years vs age < 9 years > 50 U/L: OR = 1.9, 95% CI: 1.0-3.7, P > 0.05; boys vs girls > 25 U/L: OR = 3.1, 95% CI: 2.4-4.1, P < 0.0001; > 50 U/L: OR = 2.1, 95% CI: 1.5-2.9, P < 0.0001). Impaired glucose metabolism showed a significant correlation with elevated liver enzymes > 50 U/L (OR = 4.4, 95% CI: 1.6-11.8, P < 0.005). Arterial hypertension seemed to occur in patients with elevated liver enzymes > 25 U/L (OR 1.6, 95% CI: 1.2-2.0, P < 0.005).

Conclusions: NAFLD is strongly related to extreme obesity in male adolescents. Moreover impaired glucose tolerance was observed in patients with elevated liver enzymes > 50 U/L, but arterial hypertension was only present in patients with moderately elevated liver enzymes > 25 U/L.

Keywords: Childhood obesity; Impaired glucose tolerance; Liver echogenicity; Liver enzymes; Male gender; Non-alcoholic fatty liver disease.