Resistin concentrations before and after weight loss in obese children

The influences of gender, puberty, and obesity on resistin levels and the longitudinal relationships between insulin resistance, weight loss, and resistin have not yet been studied in childhood.

Age, pubertal stage, gender, weight status (standard deviation score-body mass index (SDS-BMI)), resistin levels, and insulin resistance index calculated by homeostasis model assessment (HOMA) were evaluated in 63 obese children and compared to 36 lean children of same age, gender, and pubertal stage. Furthermore, we analyzed the changes of weight status (SDS-BMI, percentage body fat based on skinfold measurements), waist-to-hip ratio, resistin, and HOMA over a 1-year period in 38 obese children.

The resistin levels did not significantly (P = 0.079) differ between obese (median resistin 8.7 ng/ml) and lean children (median resistin 9.7 ng/ml). Resistin concentrations were independent of age and pubertal stage, but girls demonstrated significantly higher resistin levels than boys (P = 0.021). There were no significant correlations between changes of resistin and changes of SDS-BMI (r = 0.14, P = 0.198), changes of percentage body fat (r = -0.01, P = 0.466), changes of waist-to-hip ratio (r = 0.17, P = 0.141), and changes of insulin resistance index (r = 0.01, P = 0.472) over the 1-year period. The weight loss of > or = 0.5 SDS-BMI in 16 children was associated with a significant decrease in HOMA (P = 0.030), while there was no significant change in resistin levels (P = 0.878).

Girls demonstrated higher resistin concentrations than boys. Our data do not support a relationship between resistin, insulin resistance index, and weight status in childhood.