United States hypothyroidism, prevalence

In areas of the world in which the soil is deficient in iodide, hypothyroidism is prevalent. The thyroid gland enlarges (forms a goiter) in an attempt to produce more thyroid hormone. In the United States, table salt (NaCI) enriched with iodide (iodized salt) is used to prevent hypothyroidism caused by iodine deficiency. 

Other recent data regarding thyroid disease prevalence in the United States have been determined as a result of research on more focused issues, or in studies of specific groups within the overall population. While these studies may not be representative of the population as a whole, they give important insights into the prevalence of hypothyroidism. 

The frequency of hypothyroidism has been studied in some specific circumstances in the United States. The chief among these has been congenital hypothyroidism, which has long been seen as one of the most common preventable causes of mental retardation. Screening for congenital hypothyroidism began in North America in 1972. Dussault et al. summarized the first miUion newborns screened at three sites in the United States and two in Canada. Primary hypothyroidism was identified in one in 4254 births secondary—tertiary hypothyroidism occurred in one in 100000 births. In addition, the prevalence of TBG deficiency was found to be one in 8913 births ishst et al., 1979). 

---