Adiponectin and insulin resistance in childhood obesity.

OBJECTIVES: To measure adiponectin serum levels in Greek children and adolescents and correlate them with body fat and insulin resistance. PATIENTS AND METHODS: Forty-six obese prepubertal children (19 M, 27 F) and 34 obese adolescents (17 M, 17 F) ages 9.33 +/- 1.57 and 13.6 +/- 1.42 years, respectively, and 43 matched control individuals were studied. Body mass index standard deviation score and percent body fat were measured by bioelectric impedance analysis. Fasting indices of insulin resistance (HOMA-IR and fasting glucose-to-insulin ratio) were calculated for all participants. Indices of insulin resistance derived from oral glucose tolerance tests were estimated in obese participants. Adiponectin was measured by enzyme-linked immunosorbent assay.
RESULTS: (MEAN +/- SD):: Adiponectin serum levels were significantly lower in obese participants than in nonobese participants (8.11 +/- 3.80 vs 11.81 +/- 4.98 microg/mL, P < 0.001), in obese children than in nonobese children (8.86 +/- 3.86 vs 13.08 +/- 5.48 microg/mL, P < 0.001), in obese adolescents than in nonobese adolescents (7.04 +/- 3.43 vs 10.47 +/- 4.10 microg/mL, P = 0.002), and in obese adolescent boys than in obese adolescent girls (5.87 +/- 3.52 vs 8.31 +/- 3.16 microg/mL, P = 0.042). There were significant correlations between adiponectin and age, body mass index, body mass index standard deviation score, homeostasis model assessment for insulin resistance, and fasting glucose-to-insulin ratio. Adiponectin correlated with percent body fat after adjustment for sex. Adiponectin correlated significantly with several indices of insulin resistance, such as the areas under the curves for glucose and insulin, whole-body insulin sensitivity index, glucose 120', and insulin 30', in obese participants.
CONCLUSIONS: Adiponectin was significantly lower in obese participants than in nonobese participants in general, and it correlated significantly with fasting indices of insulin resistance and with indices derived from oral glucose tolerance tests. It is worthwhile to further investigate the option of applying a simple measurement of serum adiponectin as a screening tool before applying more time-consuming techniques in young obese individuals.