Correlation Between Subclinical Hypothyroidism and Dyslipidemia

Background & Objective: Thyroid hormones have an important role in the regulation of lipid metabolism. Subclinical hypothyroidism (SCH), defined as a mild increase in thyroid-stimulating hormone (TSH) and normal level of thyroxine (T4), could be associated with altered lipid profile. The current study aimed at assessing the association between SCH and changes in lipid profile. Methods: Data of 53 patients with SCH and 53 euthyroid cases were collected from Besat Hospital in Hamadan, Iran, in 2013. The age range of the cases was 18 to 60 years, and the groups were matched in terms of gender, age, and body mass index (BMI). SCH was defined as a TSH value of 4.2 to 10 mU/L, and normal T4 as 0.8 to 2.8 ng/dL. Control cases had a normal TSH ranging from 0.5 to 4.2 mU/L. The total serum cholesterol (TCHOL), high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, and triglyceride (TG) levels in both groups were examined and the results were recorded. Results:Participants with SCH had significantly higher LDL and lower HDL levels than the control group regardless of age group and gender (P-value <0.001), but there was no difference in TG and TCHOL levels (P-value <0.05). The prevalence of dyslipidemia and SCH was only significant in females (P-value =0.009). Totally, there was significant correlation between the prevalence of dyslipidemia and SCH regardless of gender (P-value =0.04). Conclusion: SCH is associated with dyslipidemia, and biochemical screening for thyroid dysfunction is recommended in all patients with dyslipidemia.