The Colorado Thyroid Disease Prevalence Study

Abstract

THE PREVALENCE of abnormal thyroid function continues to be debated. Numerous studies from various countries differ in their prevalence estimates for both hypothyroidism and hyperthyroidism. The difficulty with many of these studies lies in the variable definitions of disease states, the poorly defined and diverse populations studied, and the historically insensitive measures of thyroid function. In perhaps the best longitudinal study conducted to date, Tunbridge et al¹ found that 7.5% of women and 2.8% of men of all ages in Whickham, England, had serum thyrotropin (thyroid-stimulating hormone [TSH]) levels greater than 6 mIU/L. After reviewing 12 such studies across many different cultures, Vanderpump and Tunbridge² concluded that primary thyroid gland failure (TSH >6 mIU/L) occurs in 5% of multiple populations.