Abstract: Objective  To investigate the relationship between thyroid hormone level and insulin resistance among nondiabetic population with normal thyroid functions. Methods  Relying on the REACTION Research initiated by Chinese Medical Association in 2011， totally 5 428  individuals who met the research requirements were selected in Dalian. The following data were collected， including height， weight， blood pressure， OGTT， the levels of blood lipids， blood creatinine， blood uric acid， blood glucose， glycosylated hemoglobin， fasting insulin， thyroid function indicators， and HOMAIR. The whole group was divided into two teams， team A with TSH levels lower than 2.5  mIU/L and  team B with TSH levels higher than 2.5  mIU/L. The same items above between  two teams were compared. The relationship between thyroid hormone level and insulin resistance was studied.  Results  Compared with team A， team B had lower levels of blood creatinine， blood uric acid and FT4 and higher levels of   LDL， cholesterol， glycosylated hemoglobin， fasting insulin and HOMAIR (P＜0.05). There was a positive correlation between TSH level and HOMAIR (r=0.145，P=0.000）  and a positive correlation between FT3 level and HOMAIR as well (r=0.040，P=0.003)， while there was a negative correlation between FT4 level and HOMAIR (r=0.017，P=0.000). Logistic regression analysis showed that gender， diastolic blood pressure， BMI， HDL， LDL， cholesterol， glycosylated hemoglobin， blood uric acid， TSH and FT4 were independently the risk factors to affect HOMAIR (P＜0.05)， in which HDL and FT4 were protecting factors (P＜0.05). Conclusion  There is a positive correlation between TSH level within normal ranges and insulin resistance of nondiabetic people， while there is a negative correlation between FT4 and insulin resistance. In addition， TSH and FT4 are the independent risk factors affecting insulin resistance.

Key words: nondiabetic, thyroid hormones, insulin resistance