Subclinical hypothyroidism is thought to occur in 4.3 -- 8.5 % of people in the United States .
Subclinical hypothyroidism is a milder form of hypothyroidism characterized by normal thyroxine levels and an elevated TSH level .
Subclinical hypothyroidism , a milder form of hypothyroidism characterized by normal thyroxine levels and an elevated TSH level , is thought to occur in 4.3 -- 8.5 % of people in the United States .