Disturbed lipid metabolism in patients with subclinical hypothyroidism: effect of L-thyroxine therapy.
To evaluate whether patients with subclinical hypothyroidism have a disturbance in lipid metabolism, and whether supplemental L-thyroxine (L-T4) therapy would improve their lipid parameters, we measured serum levels of thyroid hormones, TSH and lipid parameters in 34 patients with subclinical hypothyroidism before and 2 months after treatment with L-T4. Before treatment, patients with subclinical hypothyroidism had elevated serum low density lipoprotein cholesterol (LDL-C) concentrations compared with control subjects (P < 0.05). Overall, L-T4 therapy significantly decreased the serum level of TSH (P < 0.01), total cholesterol (TC; P < 0.02), high density lipoprotein cholesterol (P < 0.02), LDL-C (P < 0.05), and the ratio of apolipoprotein B to apolipoprotein A1 (P < 0.05). Lipid values in patients with basal serum TSH levels below 10 mU/l were not affected by L-T4 therapy, whereas serum levels of TC and LDL-C decreases significantly (P < 0.01) in patients with serum TSH levels above 10 mU/l. Thus, the L-T4 treatment appears to have a preventive effect on the disturbance of lipid metabolism in patients with subclinical hypothyroidism, especially in patients with serum TSH levels above 10 mU/l.
Miura
S
S
Fourth Department of Internal Medicine, Saitama Medical School.
Iitaka
M
M
Yoshimura
H
H
Kitahama
S
S
Fukasawa
N
N
Kawakami
Y
Y
Sakurai
S
S
Urabe
M
M
Sakatsume
Y
Y
Ito
K
K
D000328:Adult; D001053:Apolipoproteins / Q000097:blood; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D005260:Female; D006111:Graves Disease / Q000097:blood / Q000188:drug therapy*; D006801:Humans; D008055:Lipids / Q000097:blood*; D008297:Male; D008875:Middle Aged; D013960:Thyroid Function Tests; D013967:Thyroiditis, Autoimmune / Q000097:blood / Q000188:drug therapy*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood / Q000627:therapeutic use*
D001053:Apolipoproteins; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D008055:Lipids; D013972:Thyrotropin; D002784:Cholesterol; D013974:Thyroxine