Supplementary Material for: Serum Uric Acid Levels as an Indicator for Metabolically Unhealthy Obesity in Children and Adolescents

Background: Metabolically healthy obesity (MHO) refers to those individuals who do not show cardiometabolic abnormalities. Our aim was to identify potential clinical and metabolic indicators that may help to distinguish between metabolically healthy and unhealthy individuals amongst overweight and obese children and adolescents. Methods: The study involved 246 overweight/obese and 212 normal-weight individuals enrolled in the LIFE Child study, aged between 6 and 18 years. Overweight/obese individuals without cardiovascular risk factors (fasting serum lipids, blood pressure, and glucose) were classified as MHO. Individuals meeting 1 or more criteria of cardiovascular risk factors were classified as metabolically unhealthy obesity (MUO). Results: Among the 246 overweight/obese individuals, 173 (70%) were MHO and 73 (30%) were MUO. The MHO individuals were younger, more likely to be male, and had lower BMI SDS. In the logistic regression models, uric acid (UA) SDS (OR 1.61, 95% CI 1.1–2.6, p = 0.004), waist circumference SDS (OR 2.50, 95% CI 1.2–6.4, p = 0.017), and C-peptide (OR 4.05, 95% CI 3.5–91, p = 0.003) were significant indicators of MUO. Conclusion: Our results suggest that nearly one-third of overweight/obese children are already identified as MUO. Serum levels of UA can be used as an indicator of unhealthy obesity in youth, where lower levels of UA indicate a lower risk and higher levels suggest a higher risk of MUO. We note that the relevance of identifying potential indicators remains the first most important step in future clinical research.