The aim of the present study was to evaluate the association of irisin with obesity and metabolic syndrome (MetS) in Korean prepubertal children. A total of 96 children and adolescents aged 6 to 10 years (56 males) were included in this study. Subjects were divided into 3 groups: normal weight (n = 54), overweight (n = 16), and obese (n = 26). In the subgroup analyses, overweight/obese children were further divided based on their MetS status (with MetS vs. without MetS). Children with obesity tended to exhibit a lower mean irisin concentration compared to those with normal weight (p = 0.028). Using Pearson's correlation coefficient to compare all the children in the study, there was a significant inverse correlation between irisin and body mass index (BMI) standard deviation scores (SDS) (r = -0.210, p = 0.041), waist circumference SDS (r = -0.203, p = 0.049), and glucose (r = -0.296, p = 0.004). In the subgroup analyses of overweight/obese children, irisin exhibited a significant inverse correlation with glucose (r = -0.507, p = 0.001) and triglycerides (r = -0.331, p = 0.033). Children with MetS exhibited lower irisin concentrations than those without MetS (14.70 ng/mL vs. 22.02 ng/mL, p = 0.001), and these associations were significant after adjusting for age, gender, and BMI SDS (14.51 ng/mL vs. 22.06 ng/mL, p = 0.002). The irisin level of 15.43 ng/mL was determined to be a possible cutoff to distinguish children with metabolic syndrome from overweight/obese children, with a sensitivity of 75% and a specificity of 94% (p < 0.001). Our results suggest that decreased irisin levels may be associated with MetS in prepubertal children and that irisin might be a biomarker for MetS in prepubertal children.
Keywords: Children; Irisin; Metabolic syndrome; Obesity; Overweight.