Independent effects of liver disease and chronic alcoholism on thyroid function and size: The possibility of a toxic effect of alcohol on the thyroid gland

Abstract

In an autopsy study we found thyroid volume significantly decreased in alcoholics with liver cirrhosis as compared to matched controls: 15 mL (range, 7 to 37 mL) v 25 mL (range, 13 to 90 mL) ( P < .01). At the same time the amount of fibrosis of the thyroid glands was higher in the alcoholics as compared to the matched controls: 20% (range, 6% to 40%) v 12% (range, 6% to 23%) ( P < .01). In order to evaluate the relative importance of alcohol consumption and liver disease on thyroid function and ultrasonically determined size, three groups of patients and matched controls (sex, age, weight, and smoking habits) were investigated: group 1, 18 patients with nonalcoholic liver cirrhosis; group 2, 21 consecutive chronic alcoholics (>100 g of alcohol daily for >5 years) without liver cirrhosis (all had biopsy proven fatty change or normal liver); group 3, 31 nonalcoholic patients with chronic nonhepatic, nonrenal disease. In group 1 median thyroid volume and serum FT 4I, FT 3I, and TSH levels were unchanged compared with the controls. In group 2 median thyroid volume was 13 mL (range, 9 to 32 mL) compared with 27 mL (range, 12 to 44 mL) in the controls ( P < .005). Serum T 3 and FT 3I levels were reduced, while T 4, FT 4I, and TSH levels were unaltered. In group 3 serum T 3 and FT 3I levels were reduced while serum FT 4I and TSH levels and thyroid volume were unaltered compared with the controls. It is suggested that alcohol may have a toxic effect on the thyroid gland independent of the degree of liver damage.