ObjectiveTo explore the correlation between IL-6-634C/G gene promoter polymorphism and body mass index (BMI),blood sugar (BS),25-hydroxy vitamin D (25-OH-D),and serum lipid levels by investigating in 8-12-year-old Han children in Shanxi province,China.MethodsIn Datong city of Shanxi province,214 8-12-year-old children were enrolled after obtaining informed consent from their parents.The weight and height were measured and the BMI was calculated.BS,serum lipids,and 25-OH-D were determined.IL-6-634C/G polymorphism were detected by polymerase chain reaction restricted fragment length polymorphism.The effects of genotype on BMI,BS,serum lipids,and 25-OH-D were also studied.ResultsThe genotypes of IL-6-634C/G polymorphism in 214 cases were GG ( 15％ ),GC (40％),and CC (45％).The percentages of C and G allele frequencies were 65％ and35％.The genotypes and allele frequencies showed no gender differences ( P ＞ 0.05 ).However,significantly different GG genotypes frequencies were found between overweight and obese children (38.3％) and other children ( normal weight children: 7.3％ ; thin children: 10.9％ ) (x2 =14.715,P =0.006).Multivariate logistic regression analysis showed that IL-6-634C/G polymorphisms and triglyceride were correlated with overweight and obesity (P ＜ 0.05 ).25-OH-D was not correlated with BMI (r =0.075,P =0.528),BS ( r =0.018,P =0.880 ),triglyceride ( r =- 0.097,P =0.417 ),high density lipoprotein cholesterin ( r =0.038,P =0.751 ),and low density lipoprotein cholesterin ( r =- 0.028,P =0.817 ).25-OH-D was not significantly different between overweight and obesity children.The distribution of three genotypes showed no correlation with 25-OH-D deficiency (x2 =0.622,P =0.733 ).ConclusionsIL-6-634C/G polymorphism exists in Han children in Shanxi province.IL-6 gene 634 GG genetype is a risk factor of childhood overweight and obesity,and may affect lipid metabolism.However,it has no direct impact on glucose metabolism.IL-6 gene 634C/G polymorphism and serum 25-OH-D are not relevant.IL-6 gene 634C/G polymorphism is not related to vitamin D deficiency diseases,and may be not related to bone calcium metabolism.25-OH-D is not relevant with BS and blood lipids level,and also is not associated with childhood overweight and obesity.