Association of body mass index with serum uric acid in shorter children and adolescents

Objective To investigate the independent association of the body mass index(BMI)with serum uric acid among shorter children and adolescent.Methods A cross-sectional study was conducted to collect general clinical data of 922 subjects with shorter statures.In each case,their information about height,weight,insulin-like growth factor-Ⅰ(IGF-Ⅰ),growth hormone peak,uric acid,and blood lipids were collected,and their BMI and BMI standard deviations score(SDS)were calculated.Smooth curve fitting and multiple piecewise linear regression were used to analyze the relationship between BMI SDS and uric acid.Results Univariate analysis found that serum uric acid was positively correlated with age,height standard deviation score,body weight standard deviation score,BMI SDS,IGF-Ⅰstandard deviation score,growth hormone peak,triglyceride,and creatinine(P<0.05),while negatively correlated with high-density lipoprotein-cholesterol(P<0.01).Female had significantly lower serum uric acid levels than male(P=0.003).The serum uric acid level was significantly increased after puberty(P<0.01).After adjusting for potential confounders,the smooth curve fitting revealed a U-shaped relationship between BMI SDS and uric acid,with a BMI SDS inflection point of-0.7.In the population of BMI SDS<-0.7,for every unit increase of BMI SDS,serum uric acid decreased by 11.78μmol/L(P=0.030).In the population of BMI SDS≥-0.7,uric acid increased by 11.79μmol/L(P<0.01)for every unit increase of BMI SDS.Conclusion Serum uric acid levels seem to be affected by BMI,and increased in population with thinness or obesity.We should pay attention to the measurement of serum uric acid in both thin and obese children.