Prevalence of the metabolic syndrome in Zhejiang Chinese obese children and adolescents and the effect of metformin combined with lifestyle intervention

Objective: We aimed to evaluate the prevalence of metabolic syndrome ( MS) in a group of obese children and adolescents in Zhejiang in the south of China, and to compare risk factors such as insulin resistance, adiponectin level and impaired glucose tolerance ( IGT) etc with that of simple obese group ( SOB) and non-obese healthy group, and also to evaluate the effect of metformin and lifestyle intervention in MS group by up to a 3-month follow-up. Methods: Three hundred and forty eight moderately or severely obese adolescents aged between 7 and 16 years were enrolled. Oral glucose tolerance test ( OGTT), biochemical indicators, blood pressure and body mass index ( BMI) were assessed in all of them. Three subgroups were selected ( MS group, SOB and healthy control). Adiponectin levels, Whole body insulin sensitive index ( WBISI), homeostasis model of insulin resistance ( HOMA-IR), plasma lipid and blood pressure were compared in these three groups. Thirty out of thirty-six MS subjects with age over 10 years received metformin treatment combined with lifestyle modification. Results: ( 1) The prevalence of MS was 10.34% among all obese subjects, which increased with the severity of obesity and reached 22.1% in severely obese children and adolescents. The occurrence of more than one complication reached 72.13%. The incidence of type 2 diabetes and IGT were 1.44 and 1.44% respectively. ( 2) BMI, waist-to-hip ratio ( WHR) and HOMA-IR increased stepwise in the control group, SOB and MS group, whereas serum adiponectin and WBISI decreased stepwise ( all P < 0.01). Systolic pressure, triglyceride, total cholesterol, low-density lipoprotein cholesterol and postprandial 2-h blood glucose in the MS group increased significantly compared to those in control and SOBs ( all P < 0.01). A correlation analysis showed that serum levels of adiponectin and WBISI were associated with the components of MS ( all P < 0.05). ( 3) After metformin and lifestyle intervention, clinical symptoms were ameliorated, serum adiponectin levels were actually increased and HOMA-IR was dropped in 20/30 MS children who had finished a 3-months follow-up ( all P < 0.01). Conclusion: The prevalence of MS in severely obese children and adolescents in Zhejiang area has reached a high level. Insulin resistance and hypoadiponectinemia were found in these MS children. Metformin combined with lifestyle modification was confirmed to be efficient and safe in treating the obese adolescents with MS.