Fat cell size, insulin sensitivity, and inflammation in obese children.

OBJECTIVE: To assess the association between adiposity indexes (body mass index [BMI], fat mass, adipocyte size) and circulating inflammation markers with known metabolic relevance or insulin sensitivity in overweight/obese children. STUDY DESIGN: Twenty-eight children (males/females: 13/15) with different degrees of overweight (BMI z-score: 1.64-3.1; fat mass: 14.1-49.8 kg) were studied. BMI, body composition (dual-energy x-ray absorptiometry scanning), subcutaneous adipocyte diameter (needle biopsy of subcutaneous abdominal fat), blood tumor necrosis factor-alpha and interleukin-6 concentrations and insulin sensitivity (frequently sampled intravenous glucose tolerance test) were assessed. RESULTS: Adipocyte diameter, more than BMI and fat mass, was significantly associated with interleukin-6 (r = 0.62, P < .001) and tumor necrosis factor-alpha (r = 0.61, P < .001). Moreover adipocyte size was associated with insulin sensitivity (R2 = 0.15, F = 4.69, P = .04) independently from fat mass. CONCLUSIONS: Adipocyte size is a factor linked to both inflammation and insulin resistance in overweight/obese children. This is similar to the findings in adults and lends support to the tenet that the earlier obesity ensues, the more severe the biologic consequences may be