IMPACT OF SUBCLINICAL HYPOTHYROIDISM ON LIPID METABOLISM AND ATHEROSCLEROSIS

Abstract

Subclinical hypothyroidism, characterized by elevated thyroid-stimulating hormone (TSH) with normal free thyroxine (fT4) levels, has been increasingly linked to alterations in lipid metabolism and early atherosclerotic changes. This study aimed to evaluate the impact of subclinical hypothyroidism on lipid profiles, systemic inflammation, and carotid intima-media thickness (CIMT) as a marker of subclinical atherosclerosisThe study tested and measured biochemical and vascular characteristics in 160 people—80 with subclinical hypothyroidism and 80 controls with normal thyroid function.  Each patient’s fasting blood was studied for TSH, fT4, total cholesterol, LDL-C, HDL-C, triglycerides, lipoprotein(a) and hs-CRP levels.  CIMT was measured with B-mode ultrasonic imaging.  Between-group comparisons were made through T-tests and Pearson correlation coefficients were used to check relations between vascular indicators, thyroid function and cholesterol. Total cholesterol, LDL-C, triglycerides, lipoprotein(a) and hs-CRP were found to be significantly increased in subclinical hypothyroidism compared to people with normal thyroid function (p < 0.01 for all).   At the same p-value, levels of HDL-C were found to be lower: 42.1 ± 5.8 mg/dL instead of 49.8 ± 7.1 mg/dL.  There was better evidence of atherosclerosis in the subclinical hypothyroid group, as their CIMT was higher at 0.84 ± 0.12 mm versus the 0.68 ± 0.10 mm group (p = 0.01).  Those with subclinical hypothyroidism often have higher levels of bad cholesterol, more general body inflammation and early changes in their arteries that may lead to atherosclerosis.  They indicate that finding and following people with subclinical thyroid problems helps reveal increased heart disease risk.