Nonlinear association between serum uric acid/serum creatinine ratio and overweight/obesity in children and adolescents

Background Childhood and adolescent obesity is a major global public health challenge and is closely associated with various metabolic diseases. Although there have been studies on the relationship between serum uric acid (SUA) and obesity, the relationship between obesity and serum uric acid/serum creatinine ratio (SUA/SCr ratio) in children and adolescents remains understudied. This study aims to investigate the nonlinear association between the SUA/SCr ratio and overweight/obesity and assess its potential as an obesity risk indicator.Methods This study utilized data from the 2013–2020 National Health and Nutrition Examination Survey, analyzing data from 3,313 children and adolescents aged 12–19 years. A multivariable logistic regression model was used to analyze the relationship between the SUA/SCr ratio and overweight/obesity, and restricted cubic regression (RCS) and piecewise regression models were employed to explore nonlinear relationships and threshold effects.Results The SUA/SCr ratio was significantly positively associated with overweight/obesity (OR = 1.34; 95% CI 1.29–1.39; P < 0.001). Subgroup analyses indicated that the correlation was highly stable. The risk of overweight/obesity increased gradually as the SUA/SCr ratio rose from low to moderate levels; when the ratio reached 10.750, the risk plateaued, demonstrating an apparent threshold effect.Conclusion The SUA/SCr ratio exhibits a significant nonlinear relationship with overweight/obesity in children and adolescents, with 10.750 as the critical threshold. This indicator can serve as an important reference for obesity risk assessment, particularly for early intervention within the threshold range, which may provide an important reference for early risk assessment and preventive strategies for overweight and obesity in children and adolescents.