Metformin use in children with obesity and normal glucose tolerance--effects on cardiovascular markers and intrahepatic fat.

Objective: To determine if metformin improves markers of inflammation, thrombosis, and intrahepatic fat contents in children with uncomplicated obesity. Methods: Obese children with normal glucose tolerance but elevated highly sensitive C-reactive protein (hsCRP) and/or fibrinogen concentrations (>2 standard deviations) were randomized to structured diet/exercise or diet/exercise and metformin for 6 months. Blood samples, dual energy X-ray absorptiometry data, and liver magnetic resonance images were obtained. Results: Forty-two of 66 recruited children (7-18 years) completed 6 months. Weight loss was modest but more pronounced in the metformin group (-4.9 +/- 1.0 kg) than in the diet/exercise group (-1.7 +/- 1.1 kg, p < 0.03), whereas hsCRP and fibrinogen decreased more in the diet/exercise pubertal group. Baseline intrahepatic fat was high but decreased only in the diet/exercise (not metformin) pubertal group. Conclusions: Six months of metformin therapy improved weight loss and reduced abdominal adiposity, but did not enhance the beneficial effect of diet and exercise on markers related to inflammation, thrombosis, or hepatic fat in obese children with normal glucose tolerance.