Thyroid disorders in chronic hepatitis C

Purpose To explore the association of hepatitis C virus (HCV) infection with thyroid disorders. Methods We investigated the prevalence of thyroid disorders in 630 consecutive patients with chronic hepatitis due to HCV infection; all patients were free of cirrhosis and hepatocarcinoma, and were not on interferon treatment. Also included were a control group of 389 subjects from an iodine-deficient area, another control group of 268 persons living in an area of iodine sufficiency, and 86 patients >40 years of age with chronic hepatitis B. Levels of thyroid-stimulating hormone (TSH), free thyroxine (T4), and triiodothyronine (T3), as well as anti–thyroglobulin and anti–thyroid peroxidase antibodies, were measured. Results Mean TSH levels were higher (P = 0.001), and free T3 and free T4 levels were lower (P<0.0001), in patients with chronic hepatitis C than in all other groups. Patients with chronic hepatitis C were more likely to have hypothyroidism (13% [n = 82]), anti–thyroglobulin antibodies (17% [n = 108]), and anti–thyroid peroxidase antibodies (21% [n = 132]) than were any of the other groups. Conclusion Both hypothyroidism and thyroid autoimmunity are more common in patients with chronic hepatitis C—even in the absence of cirrhosis, hepatocellular carcinoma, or interferon treatment—than in normal controls or those with chronic hepatitis B infection.