Correlation between Thyrotropin and Fasting Lipid Profile in Patients of Sub Clinical Hypothyroidism

Farhat Ijaz,Rana Khurram Aftab,Syed Mohammad Zubair

doi:10.21649/akemu.v23i2.1568

Abstract

AbstractA controversy exists regarding the association between subclinical hypothyroidism (SCH) and dyslipidemia. Moreover, studies on lipid ratios in SCH are rare, particularly in Asian Countries. The study also aims to find out whether any correlation exists between serum TSH levels and fasting lipid levels, which would indirectly affect morbidity and mortality.Methods: The study was conducted at Physiology department, KEMU and Centre for Nuclear Studies KEMU & Mayo Hospital, Lahore which is a tertiary-care center. It was a cross-sectional study carried out over a period of 6 months. Control group consisted of 50 euthyroid persons taken from a population coming for whole-body health checkup. Case group consisted of 50 patients with SCH. Confounding variables were removed. Fasting blood samples were taken in a plain gel vaccutainer tube with an aseptic blood collection technique. The samples were centrifuged within 1 h at 3000 rpm for 5 min. These wereprocessed to obtain serum for the estimation of serum lipid profile and Thyrotropin (TSH) hormone level.Results: The study examined the link between Thyrotropin levels and fasting lipid profile in patients of SCH versus euthyroid normal controls in a cross sectional adult population over a period of six months. Patients with SCH had significantly lower HDL-C, as compared to Controls. The Lipid profiles were each categorized and mean Thyrotropin levels were higher in subjects in the dyslipidemic sub-class than subjects in normal sub-class. Thyrotropin was positively asso-ciated with serum Triglyceride and negatively associated with HDL-C in cases of SCH. Thyrotropin is also positively associated with Total Cholesterol (TC) along with VLDL-C and LDL-C. In the Euthyroid (Control Group) population, Thyrotropin was positively associated with TC.Conclusion: To conclude, Serum Thyrotropin was correlated with dyslipidemia in SCH and euthyroid subjects. In simple words, when Thyrotropin (TSH) increases upto 10 mIU/L the signs and symptoms of Hypothyroidism are not manifested, but chemical changes start to take place in the body, and the lipid metabolism is starting to take its toll. In SCH patients, TC, Triglyceride, LDL-C, HDL-C, start to rise as compared to normal euthyroid control groups. Thus there is a positive correlation between lipids and Thyrotropin, less HDL, which exhibited negative correlation in SCH subjects.AbstractA controversy exists regarding the association between subclinical hypothyroidism (SCH) and dyslipidemia. Moreover, studies on lipid ratios in SCH are rare, particularly in Asian Countries. The study also aims to find out whether any correlation exists between serum TSH levels and fasting lipid levels, which would indirectly affect morbidity and mortality.Methods: The study was conducted at Physiology department, KEMU and Centre for Nuclear Studies KEMU & Mayo Hospital, Lahore which is a tertiary-care center. It was a cross-sectional study carried out over a period of 6 months. Control group consisted of 50 euthyroid persons taken from a population coming for whole-body health checkup. Case group consisted of 50 patients with SCH. Confounding variables were removed. Fasting blood samples were taken in a plain gel vaccutainer tube with an aseptic blood collection technique. The samples were centrifuged within 1 h at 3000 rpm for 5 min. These wereprocessed to obtain serum for the estimation of serum lipid profile and Thyrotropin (TSH) hormone level.Results: The study examined the link between Thyrotropin levels and fasting lipid profile in patients of SCH versus euthyroid normal controls in a cross sectional adult population over a period of six months. Patients with SCH had significantly lower HDL-C, as compared to Controls. The Lipid profiles were each categorized and mean Thyrotropin levels were higher in subjects in the dyslipidemic sub-class than subjects in normal sub-class. Thyrotropin was positively asso-ciated with serum Triglyceride and negatively associated with HDL-C in cases of SCH. Thyrotropin is also positively associated with Total Cholesterol (TC) along with VLDL-C and LDL-C. In the Euthyroid (Control Group) population, Thyrotropin was positively associated with TC.Conclusion: To conclude, Serum Thyrotropin was correlated with dyslipidemia in SCH and euthyroid subjects. In simple words, when Thyrotropin (TSH) increases upto 10 mIU/L the signs and symptoms of Hypothyroidism are not manifested, but chemical changes start to take place in the body, and the lipid metabolism is starting to take its toll. In SCH patients, TC, Triglyceride, LDL-C, HDL-C, start to rise as compared to normal euthyroid control groups. Thus there is a positive correlation between lipids and Thyrotropin, less HDL, which exhibited negative correlation in SCH subjects.Keywords: Dyslipidemia, lipid profile, subclinical hypothyroidism.

Highlights

Serum lipid ratios such as Total Cholesterol (TC)/highdensity lipoprotein-cholesterol (TC/HDL-C), TG/HDL-C, and LDL-C/HDL-C have been shown to be better predictors of cardiovascular risk compared to conventional lipid profile.[10]
We conducted a cross sectional–control study, where we studied patient who were asymptomatic for Hypothyroid, but their TSH levels were below 10 ImU/L to investigate the status of their fasting lipid profile and compared them with 50 persons with normal TSH levels as controls
This study investigated the relationship between serum Thyrotropin (TSH) levels and dyslipidemia in subclinical hypothyroid and euthyroid subjects

Summary

Introduction

Subclinical hypothyroidism (SCH), is described as a condition which presents with elevated serum level of Thyrotropin (TSH) normal levels of free Thyroxin (T3)ANNALS VOL 23, ISSUE 2, APR. – JUN. 2017 137SYED MOHAMMAD ZUBAIR, FARHAT IJAZ, RANA KHURRAM AFTAB and free Tetriodothyronine (T4), is a common disorder having a prevalence of about 7.5–8.5% in females and 2.8–4.4% in males, worldwide.[1,2]Numerous studies have shown that overt hypothyroidism is associated with abnormalities of lipid metabolism such as elevated lipids viz. VLDL( Very low density Lipoprotein) LDL (Low Density Lipoprotein) TC (Total Cholesterol) and Triglycerides (TG) thereby predisposing individuals to vascular diseases.[3,4,5] the association of SCH with abnormalities in lipid parameters have been studied with conflicting results.[4,6] Some studies have shown a link between SCH and metabolic syndrome while others have been unable to prove this.[7,8] Numerous studies have depicted that even little alterations in TH serum status within the reference range might influence the severity of atherosclerosis.[9] a days, serum lipid ratios such as TC/highdensity lipoprotein-cholesterol (TC/HDL-C), TG/HDL-C, and LDL-C/HDL-C have been shown to be better predictors of cardiovascular risk compared to conventional lipid profile.[10]. Subclinical hypothyroidism (SCH), is described as a condition which presents with elevated serum level of Thyrotropin (TSH) normal levels of free Thyroxin (T3). Numerous studies have shown that overt hypothyroidism is associated with abnormalities of lipid metabolism such as elevated lipids viz. VLDL( Very low density Lipoprotein) LDL (Low Density Lipoprotein) TC (Total Cholesterol) and Triglycerides (TG) thereby predisposing individuals to vascular diseases.[3,4,5] the association of SCH with abnormalities in lipid parameters have been studied with conflicting results.[4,6] Some studies have shown a link between SCH and metabolic syndrome while others have been unable to prove this.[7,8] Numerous studies have depicted that even little alterations in TH serum status within the reference range might influence the severity of atherosclerosis.[9]. Small dense LDL, a subtype of LDL has been described as the main determinant of the atherogenicity of LDL-C.10 studies on the complex interrelationship between SCH and lipid have been extremely rare

Methods

Results

Discussion

Conclusion