Sex-related differences between adiponectin and insulin resistance in schoolchildren

OBJECTIVE - To study the effect of body composition and adiponectin on insulin resistance and beta-cell function in schoolchildren during puberty. RESEARCH DESIGN AND METHODS - Plasma adiponectin level and its relationships with insulin sensitivity and beta-cell function were analyzed in 500 randomly recruited nondiabetic Taiwanese schoolchildren (245 boys and 255 girls) aged 6-18 years in a national survey program for diabetes in 1999. Insulin resistance and beta-cell function were evaluated by homeostasis model assessment (HOMA). Plasma adiponectin concentrations were determined with radioimmunoassay. RESULTS - Plasma glucose levels remained stable, whereas insulin resistance increased with a compensatory rise in beta-cell function during this period. A transient drop of adiponectin level with a trough at 10-12 years was found in boys but not in girls. This pubertal drop of adiponectin levels in boys coincides with the sharp rise in testosterone concentration. A negative correlation between testosterone levels and adiponectin concentration was also noted in boys (r = -0.142, P = 0.032). Plasma adiponectin levels correlated inversely with relative body weight, fasting insulin concentrations, and insulin resistance index by HOMA in boys aged 15-18 years and in girls aged 11-14 years. No association was observed between adiponectin levels and beta-cell function by HOMA. CONCLUSIONS - There is a transient drop in the level of adiponectin during male puberty, correlated with the increase in testosterone level in boys. Plasma adiponectin levels were inversely correlated with obesity and insulin resistance in boys and girls during the pubertal period.