Abstract: Objective To explore the changes of thyroid stimulating hormone(TSH) and thyroid hormone(TH) levels in type 2 diabetic patients with different body mass index(BMI) and waist circumference(WC) and the influence of obesity on TSH and TH.Methods A total of 275 hospitalized patients with type 2 diabetes were collected.They were divided into the normal group(18.5kg/m²≤BMI<24kg/m²，88 cases),overweight group(24kg/m²≤BMI<28kg/m²，90 cases) and obesity group(BMI≥28kg/m²，97cases) according to BMI.The blood lipid levels and thyroid function among these three groups were compared.Then,them were divided into M1 group（male WC<85cm）,M2 group（male WC≥85cm）,F1 group（female WC<80cm）,F2 group(female WC≥80cm) according to gender and WC.Make a comparison among the above indexes among these groups.Spearman correlation analysis was used to analyze correlation and multiple linear stepwise regression was used for influence factor analysis.Results Compared with the normal group,TSH levels in the overweight group and obesity group were significantly increased(P<0.05).TSH level in F2 group was obviously higher than those in F1 group and M2 group,and free thyroxine（FT₄） level was lower than that in M2 group(P<0.05).The results of correlation analysis showed that BMI of type 2 diabetic patients was positively correlated with TSH(r=0.25,P<0.05),TC was negatively related with FT₃(r=-0.39,P<0.05),and BMI and WC were negatively related with FT₄(r=-0.31,r=-0.29,P<0.05).The results of multiple linear stepwise regression showed that BMI was an independent correlative factor for TSH,and WC was an independent correlative factor for FT4(P<0.05).Conclusion The TSH level of obese patients with type 2 diabetes is increased,and FT4 is decreased，which are more obvious in female patients with abdominal obesity than those in males.

Key words: Body mass index, Waist circumference, Thyroid function