Thyroid Dysfunction and Their Relation to Cardiovascular Risk Factors such as Lipid Profile, hsCRP, and Waist Hip Ratio in Korea

Abstract

BackgroundThyroid abnormalities affect a considerable portion of the population, and overt hypothyroidism is associated with an elevated risk of cardiovascular disease and adverse changes in blood lipids. Subclinical hypothyroidism is also associated with an increase risk of cardiovascular disease. So, we undertook this study to investigate the prevalence of overt and subclinical thyroid disorders and their associations with cardiovascular risk factors.Methods:This study involved 66260 subjects (43588 men, 22672 women; between 20–80 years of age, mean age 41.5±9.6). Serum free thyroxine (FT4), thyroid stimulating hormone (TSH), total cholesterol, low density lipoprotein cholesterol (LDL-C), and high density lipoprotein cholesterol (HDL-C) were measured by RIA using commercial kits. High sensitivity C-reactive protein (hsCRP) levels were determined by nephelometry.Results:The prevalences of overt thyrotoxicosis, subclinical thyrotoxicosis, overt hypothyroidism and subclinical hypothyroidism were 5/1000 (334 subjects), 6.4/1000 (426 subjects), 1.6/1000 (108 subjects), and 6.4/1000 (375 subjects). Mean plasma total cholesterol and LDL-C were elevated in overt hypothyroidism than in normal controls (202.1 mg/dL and 121.8 mg/dL versus 197.1 mg/dL and 120.1 mg/dL, respectively) (p<0.05). In subclinical hypothyroidism, mean total cholesterol and LDL-C levels were also elevated (201.9 mg/dL and 123.7 mg/dL)(p=0.015, p=0.047). Waist-to-hip ratio (WHR) was lower in overt thyrotoxicosis and higher in hypothyroidism.Conclusion:The prevalence of thyroid dysfunction in Korea is not significantly different from that reported by other countries. It was also age dependent and higher in women, but this elevation in women was lower than expected. Patients with hypothyroidism exhibited higher waist-to-hip ratios, an index of obesity. Patients with subclinical hypothyroidism exhibited elevated atherogenic parameters (Total cholesterol, LDL-C). Therefore screening and treatment for subclinical hypothyroidism may be warranted due to its adverse effects on lipid metabolism.

Lipid Profile in Hypothyroid Patients: A Cross Sectional Study

“…Jung 16 found mean plasma total cholesterol and LDL cholesterol levels elevated in hypothyroid cases than in normal controls. In another study, average serum total cholesterol level was found elevated in primary and secondary hypothyroidism 17 .…”

Frequency of subclinical thyroid dysfunction and risk factors for cardiovascular disease among women at a workplace

“…[39][40][41][42][43][44] Conflicting results have been obtained in relation to hsCRP: three studies showed some correlation, [44][45][46] while another three did not show any association at all. 39,47,48 The positive studies tended to include patients with definitive thyroid disease, as opposed to asymptomatic patients who had been found through screening. For example, the study by Christ-Crain et al 43 compared 63 women with subclinical hypothyroidism with 61 women with overt hypothyroidism and 40 euthyroid controls, but more than 40% of the women with subclinical hypothyroidism had been treated with radioiodine, surgery or anti-thyroid drugs for either for Graves disease or for toxic multinodular goiter.…”

Effect of H Dl and LDL Cholesterol on Hypothyroid Patients.

“…Many studies have reported varied types of dyslipidemias in hypothyroid patients viz; hypercholesterolemia, elevation of very low density lipoprotein (VLDL), hypertriglyceridemia etc. Jung et al found mean plasma total cholesterol and LDL cholesterol levels elevated in hypothyroid cases than in normal controls (202.1 mg/dl and 121.8 mg/dl versus 197.1 mg/dl and 120.1 mg/dl, respectively) [18]. In another study, average serum total cholesterol level was found elevated in primary and secondary hypothyroidism [19].…”