| Objective To compare the changes of thyroid hormone levels in normal glucose tolerance group and type 2 diabetes mellitus (type 2 diabetes mellitus, T2DM). The correlation between thyroid hormone and the various metabolic indices in type 2 diabetes was observed in order to explore a pathogenesis of metabolic disorders, and to look for new ways to provide a theoretical basis for treatment in type 2 diabetes.Methods Three hundred and twelve patients of type 2 diabetes mellitus were selected who stayed in Department of Endocrinology of Second Hospital of Shanxi Medical University from December in 2009 to December in 2010 (Group T2DM):one hundred and five were female, two hundred and seven were male, mean age were 56.9±9.7 years old. And ninty cases of normal glucose tolerance were selected in our hospital medical examination center in the same period (Group NGT):thirty were female, sixty were male, mean age were 56.8±8.7 years old. Patients with thyroid diseases were excluded. Patients who were using drugs which had affected the thyroid function were excluded. Patients suffered from acute illnesses (such as myocardial infarction),serious infections, trauma and others in the stress in recent period(3 months) were excluded. Patients suffered from cancer were excluded. Patients suffered from serious heart, liver, kidney failure and hypertension were excluded. Patients who were pregnant women or nursing mothers were excluded. Patients who had a history of radiation exposure were excluded. Human thyroid-stimulating hormone (hTSH), free thyroid hormone (FT4) and free triiodothyronine three (FT3) were measured by solid-phase chemiluminescence immunoassay technology. They were normally distributed measurement data. They were expressed by mean±standard deviation (x±s).The differences between the two groups were analyzed by t test. The metabolic parameters: body mass index(BMI), waist to hip ratio(WHR), total cholesterol(TC), triglyceride(TG), low density lipoprotein cholesterol(LDL-C), high density lipoprotein cholesterol(HDL-C), Apo lipoprotein A1(Apo-A1), Apo lipoprotein B(Apo-B), fasting insulin(FINS), postprandial 2h insulin(2h INS), insulin resistance index(HOMA-IR), and glycated hemoglobin(HbA1c) were independent variables. FT3 and FT4 were dependent variables respectively. Correlation between thyroid hormone and the metabolic indices above in type 2 diabetes were observed. All the normal distribution of measurement data were represented by mean±standard deviation(x±s). Non-normally distributed data were log-transformed data for the normal distribution. The normal distribution measurement data was compared by t test between the two groups. And P≤0.05 was considered statistically significant. The correlation between them were analyzed by the backward selectionof multiple linear regression,the introduction of the standard was P<0.05, excluding the standard was P> 0.1.Results1. The changes of levels of thyroid hormone and human thyroid stimulating hormone in the normal range between type 2 diabetes mellitus group and normal glucose tolerance group The levels of FT3 in the T2DM group were lower than in the NGT group (4.59±0.63 vs.5.14±0.52), the difference was statistically significant (P<0.05). The levels of FT4 in T2DM group were higher than in the NGT group (4.59±0.63 vs.5.14±0.52), the difference was statistically significant (P<0.05). The levels of hTSH were no significant difference between the two groups(2.48±1.86 vs.2.50±1.46) (P> 0.05).2. The study of thyroid hormone levels associated with the metabolism of type 2 diabetic patients. The correlation were analyzed by the backward selection of multiple linear regression. The metabolic parameters:body mass index (BMI), waist to hip ratio (WHR), total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), Apo lipoproteinAl (Apo-Al), Apo lipoprotein B (Apo-B), fasting insulin (FINS), postprandial 2h insulin (2h INS), insulin resistance index (HOMA-IR), and glycatedhemoglobin(HbA1c) were independent variables in the T2DM group. FT3 and FT4 were dependent variables respectively in the T2DM group.BMI(X1), TG(X4), HbAlc(X12) and 2hINS(X10) were related independently to FT3(Y)(Y=3.896+0.060X1-0.121X4-0.079X12-0.003 X10, P1=0.000, P4=0.002, P12=0.048, P10=0.001);LDL-C(X5), Apo-B(X8), TC(X3), and Apo-Al (X7) were related independently with FT4(Y) (Y=14.389+0.774 X5+0.854 X8-0.944X3-1.183X7, P5= 0.002, P8= 0.028, P3= 0.000, P7= 0.001).Conclusions1. The levels of FT3 in T2DM were lower than in the NGT in the normal range, while the levels of FT4 in T2DM group were higher than in the NGT group. Which showed thyroid function had changed in type 2 diabetic group, and the conversion of T4 to T3 was decreased.2. The levels of FT3 decreased in type 2 diabetes led to the reduction of glucose metabolism and the increase of insulin resistance. Which also led to the increase of the levels of triglycerides and the decrease of the levels of resting metabolic rate. |
