| Objective: The aim of the study was to evaluate the effect of metf ormin treatment in thyroid disease,by investigating the changes of thyro id function and morphology in patients with impaired glucose regulation(IGR)treated by metformin treatment,and exploring its possible mechan ism,so as to provide more clinical evidence for the accurate treatment of patients with impaired glucose regulation(IGR)plus thyroid disease.Methods:From September 2018 to February 2019,we collected 242 subjects aged 18-70 years,with no previous history of diabetes or thyroid dysfu nction,fasting blood glucose in 6.1-7.0mmol/L in Shijiazhuang.All the participants were given oral glucose tolerance tests(OGTT)and finally 90 participants with IGR were randomly divided into observation group(n=45,standard lifestyle and metformin intervention)and the control gro up(n=45,standard lifestyle intervention),however,during the 1-year fol low-upperiod,10 participants dropped out and only 80 participants comp leted,concluded 39 in the observation group and 41 in the control grou p.Wecollected baseline and general characteristics of subjects.Serum co ncentration of TSH,FT3,FT4,insulin-like growth factor 1(IGF-1)level s,fasting blood glucose(FBG),2-hour postprandial blood glucose(PBG)and fasting insulin(FINS)levels were measured,the volume and the l argest diameter of thyroid nodules and thyroid volume(left lobe + right lobe + spondylolysis)were studied by ultrasonography.We compared th e change of the above indexes between observation group and control g roup before and after treatment,and explore the possible mechanism of the change of thyroid nodules and function.Results:1.Comparison of baseline characteristics between the two groups: there had no statistically significant difference in observation and control groups(P>0.05).2.After treatment,the body weight,body mass index(BMI)and waist circumference between the two groups had no statistically significant differences(P>0.05).Paired comparison in the group before and after treatment: body weight,BMI and waist circumference in the observation group decreased,with statistically significant difference(P<0.05).There was no significant change in the control group(P>0.05).The differences of body weight,BMI and waist circumference before and after treatment between the two groups were statistically significant(P<0.05).3.After metformin treatment,FBG,PBG and HOMA-IR in the observation group were lower than control group,with statistically significant difference(P<0.05),but Hb A1 c and IGF-1 had no significantly change(P>0.05).Paired comparison in the group before and after treatment: Hb A1 c,HOMA-IR and IGF-1 in the observation group significantly decreased,with statistically significant difference(P<0.05),however,PBG and FBG showed a decreasing trend(P>0.05).In the control group,FBG increased while IGF-1 decreased after treatment,with statistically significant difference(P<0.05).4.One variable linear regression model showed that baseline TSH le vels were negatively correlated with serum TSH levels after metformin t reatment.We can explain the difference of TSH levels before and after metformin treatment by the following mathematical model: Difference(p ost-previous)=1.302-0.552(baseline TSH);P<0.001.5.There was no statistical difference in FT3,FT4 and TSH between t he two groups after treatment(P>0.05).Paired comparison in the group before and after treatment: in both group,FT4 increased and FT3 decre ased than before,with statistically significant difference(P<0.05),while TSH decreased without statistical difference(P>0.05).We divided respec tively both two groups into two subgroups according to TSH=2.36,the A subgroup(TSH?2.36 m IU/ml)and the B subgroup(TSH<2.36 m IU/ml).It suggested that the TSH of A in the observation group was significantl y reduced after intervention,and the difference was statistically significa nt(P<0.05),however,the TSH of B was no significant difference(P>0.05).In the control group,there was also no significant difference in the TSH of both subgroups(P>0.05).6.Comparison of thyroid morphology between the two groups after treatment: the thyroid volume,nodule volume,nodule number,thyroid maximum diameter and nodule maximum diameter had no statistically significant differences(P>0.05).Comparison within the group before and after treatment: in the observation group,the number of nodules decreased than before,with a statistical difference(P<0.05),and the thyroid maximum diameter,nodule maximum diameter and nodule volume showed a decreasing trend.In the control group,thyroid volume,nodule volume and nodule maximum diameter all increased,with statistical differences(P<0.05).7.We used multiple linear regression to analysis the factors affecting the TSH level.The results showed that ?waist circumference and ?IGF1 were independent factors affecting the change of TSH(P<0.05).8.We also used multiple linear regression analysis to analyze the fa ctors affecting thyroid morphology and we find that: ?IGF1 and wheth er metformin was used were independent influencing factors of the maxi mum diameter variation of nodules(P<0.05).Conclusions:1.The way of simple lifestyle intervention combined with metformin treatment can more effectively reduce the body weight and blood glucose of patients with prediabetes and improve insulin resistance.2.Metformin has a buffering effect on the secretion of TSH in patients with prediabetes and normal thyroid function,and can induce circulating TSH levels to the middle of the normal range.3.After metformin treatment,the number of thyroid nodules will reduce and nodule volume tends to decrease in patients with prediabetes.4.We speculate the mechanism that metformin can reduce TSH leve l and decrease the number of thyroid nodules may be related to weight loss and insulin resistance reduction,however,the role of IGF-1 and it s specific mechanism need to be further studied. |
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