Objective    To study the epidemiological characteristics of metabolic syndrome (MS) in normal

overweight and obese school-aged children

and the change and significance of serum inflammatory factor levels in children with MS diagnostic indexes.     Methods    Six primary schools were randomly selected from the urban districts of Chongqing

China. For grades 2-5

two classes in each grade were randomly selected for this study. A total of 1 941 children were recruited in this study. According to the overweight and obesity criteria recommended by the Group of China Obesity Task Force

all 54 obese children

as well as randomly selected 77 overweight children and 72 normal children

were used as the subjects. We divided these subjects into three groups

i.e.

a normal group (n=74) without any MS diagnostic index

a non-MS group (n=106) with 1 or 2 MS diagnostic indexes

and an MS group (n=23) with 3 or more MS diagnostic indexes. The criteria used to diagnose MS were modifications of the National Cholesterol Education Program (NCEP) ATP Ⅲ according to Cook’s criteria. Anthropometric measurement was conducted by professional persons using routine methods. Serum biochemical markers [including triglycerides (TG)

high density lipoprotein (HDL)

total cholesterol (TC)

low density lipoprotein (LDL)

glucose

and insulin] were determined by a clinical analyzer (Siemens ADVIA 2400) using standard methods. The serum levels of tumor necrosis factors-α (TNF-α)

interleukin-6 (IL-6) and high-sensitivity C reaction protein (hs-CRP) were analyzed using commercial ELISA kits.     Results    The MS rates were 27.78% (15/54)

10.39% (8/77) and 0% (0/72) in the obese

overweight and normal school-aged children

respectively. The MS rates were statistically different between overweight and obese children (P0.01). The serum levels of hs-CRP and IL-6 (1.45±1.75 mg/ml and 4.84±0.60 pg/ml) in the MS group were significantly higher than those (0.71±1.11 mg/ml and 1.71±1.10 pg/ml) in the non-MS group (P0.01). The serum levels of hs-CRP and IL-6 in the non-MS group were higher than those (0.34±0.60 mg/ml and 1.35±0.70 pg/ml) in the normal group. There was no significant difference in the serum TNF-α levels among the three groups (P0.05).     Conclusion    Our results indicate that overweight and/or obesity increase the MS rate in school-aged children. Low-grade inflammation exists in both overweight and obese children

and may increase the MS risk. Increased MS rate in obese children may be due to increased hs-CRP and IL-6 levels. Both hs-CRP and IL-6 as inflammatory factors have potential use for MS prediction.