Correlation Between TSH Level And Vascular Endothelial Function In Patients With Subclinical Hypothyroidism

Context:Subclinical hypothyroidism(SCH)is a thyroid disease in which serum thyrotropin levels are higher than the upper limit of normal and serum free thyroid hormone levels are within the normal range.Its incidence is related to age and gender.Studies have shown that its incidence increases with age,and the female incidence is higher than the male.A large number of studies have shown that TSH has a wide range of external thyroid effects,especially its influence on the function of vascular endothelial cells has attracted more and more attention.Some studies have shown that subclinical hypothyroidism can induce or aggravate atherosclerosis through lipid metabolism disorder,endothelial cell function damage,etc.But there are still different voices.Up to now,no definite consensus has been reached on the effect of subclinical hypothyroidism on arteriosclerosis,and the treatment standard of subclinical hypothyroidism still needs to be further clarified.Therefore,it is necessary to explore the correlation between TSH and vascular endothelial function from multiple perspectives,so as to provide a theoretical basis for clarifying the mechanism of TSH on atherosclerosis.Objective:To analyze the correlation between blood lipid distribution and TSH level by comparing the blood lipid distribution of people with different levels of thyroid stimulating hormone.By measuring the levels of NO,CIMT and FMD at different levels of TSH,the vascular endothelial dysfunction in patients with subclinical hypothyroidism and the correlation between different levels of TSH and vascular endothelial function were analyzed,providing a basis for the treatment of patients with subclinical hypothyroidism.Methods:The participants in the observation group were selected from the outpatients and patients admitted to our hospital from December 2016 to December 2018.Exclude patients with hypertension,diabetes,liver and kidney dysfunction,and a history of special medication in the past 3 months.According to the different levels of serum thyroid stimulating hormone(TSH)and free thyroxine(FT4),57 patients with hypothyroidism and 43 patients with subclinical hypothyroidism were selected.56 normal healthy subjects were selected as control group.With general information collection,including: Age,gender,systolic blood pressure,BMI,and determination of TSH(thyroid stimulating hormone),FT4(free thyroxine)and CRP(hypersensitive creactive protein),TG(triglyceride),TC(total cholesterol),LDL-C(low-density lipoprotein),HDL-C(high density lipoprotein),NO(nitric oxide),carotid intima thickness(CIMT),and calculate the FMD,comparison between groups in patients with blood lipid level,oxidative stress index differences,comparing carotid intima thickness and FMD in different level of TSH level group.To further clarify the correlation between subclinical hypothyroidism and endothelial function.SPSS 23.0 software was used to analyze all the data,and P<0.05 was considered as significant difference.Results:1.There were no significant differences in age,sex ratio,BMI,systolic blood pressure and HDL-C between the SCH group and the healthy control group.The mean levels of TC,TG,LDL-C,CRP and CIMT of the SCH group were higher than those of the healthy control group,with significant differences.2.There were NO significant differences in age,sex ratio,BMI,systolic blood pressure and HDL-C between the SCH group and the hypothyroidism group.The differences were statistically significant in TC,TG,LDL-C and CRP、CIMT between the SCH group and the hypothyroidism group,and statistically significant in NO and FMD between the SCH group and the hypothyroidism group(P<0.05).3.Compared with the healthy control group,there were no significant differences in age,sex ratio,BMI,systolic blood pressure and HDL-C between the hypothyroidism group and the healthy control group.The levels of TC,TG,LDL-C,CRP and CIMT in the hypothyroidism group were significantly higher than those in the normal group,and the differences were statistically significant.4.In terms of correlation,TSH is significantly correlated with TG,TC,LDL-C,FMD,CIMT and NO,and TSH is positively correlated with TG,TC,LDL-C and CIMT,while negatively correlated with FMD and NO.5.The results of multiple linear regression analysis with NO as the dependent variable showed that CRP and TSH could significantly affect NO,and the lower the levels of CRP and TSH,the higher the levels of NO.6.The results of multiple linear regression with CIMT as the dependent variable showed that BMI,TSH,TG and LDL-C could significantly affect CIMT,and CIMT increased with the increase of BMI,TSH,TG and LDL-C.7.The results of multiple linear regression with FMD as the dependent variable showed that age,BMI,systolic blood pressure,CRP,TSH,TG and LDL-C could all affect FMD,which was negatively affected by the increase of the above independent variables and the decrease of FMD.Conclusion:In subclinical hypothyroidism,elevated TSH can induce lipid metabolism disorder,oxidative stress and damage vascular endothelial cell function,affect vascular diastolic function,and promote the occurrence and development of atherosclerosis.