Increased atherogenic low-density lipoprotein cholesterol in untreated subclinical hypothyroidism.

Objective: To evaluate the effects of physiologic doses of levothyroxine replacement on the lipoprotein profile in patients with subclinical hypothyroidism (SCH).

Methods: In a prospective, double-blind, placebo-controlled study, we enrolled 120 patients--mostly, but not exclusively, premenopausal women--with SCH. Patients were randomly assigned to either a levothyroxine-treated group (n = 60) or a placebo (control) group (n = 60).