Plasma TSH levels in endemic goiter subjects

Plasma TSH levels were measured in goitrous young males living in an area of moderate iodide deficiency in the Egyptian desert (New Valley). Nongoitrous young males living in an area of the same desert where water iodide concentrations were higher (Siwa oases) and a group of normal American subjects served as controls. Plasma TSH levels were higher in the New Valley males than in either control group. Serum PBI values and urinary iodide excretions were lower in the goitrous New Valley subjects than in the Siwa controls. These data support the hypothesis that, at least in some instances, an increase in circulating TSH is a contributing factor to endemic goiter formation in subjects living in areas of mild to moderate iodide deficiency.