The assoeiation between total cholesterol and elevated thyrotropin

Han, Sang Il; Jeon, Hyo Yee; Yun, Young Ho; Yoo, Tai Woo; Huh, Bong Yul

Abstract

BACKGROUND: Hypothyroidism may be involved in a significant portion of the causes of hypercholesterolemia in Korea. In this study, we determined the frequency of suspected hypothyroidism in hypercholesterolemic patients and compared the frequency of elevated thyrotropin levels among the groups with various total cholesterol levels.
METHODS
The study subjects were healthy, asymptomatic people who visited Health Promotion Center of Seoul National University Hospital. We excluded subjects with history of hypertension, DM and hypothyroidism. The study subjects underwent physical examination and filled out a questionnaire on health risk factors. Also blood chemistry and thyroid function test were done.
RESULTS
Among 6479 subjects, 194(2.99%) had elevated(>4.1 microIU/ml) thyrotropin levels. Among the hypercholesterolemic(> or=240mg/dl) patients(n=868), 40(4.60%) had elevated thyrotropin levels. And there was statistically significant difference between normal cholesterolemic and hypercholesterolemic subjects(P<0.05). Among the patients with total cholesterol above 280mg/dl (n=180), 15(8.33%) had elevated thyrotropin levels. As amount of the total cholesterol increased, the frequency of elevated thyrotropin levels Increased(P=0.001). And this result was consistent following adjustment for age, sex, BMI, smoking and drinking status(P<0.01).
CONCLUSIONS
Practicing physicians should be aware of the possibility of secondary hypercholesterolemia due to hypothyroidism and keep in mind the importance of evaluating TSH level.