A recent review limited to subclinical hypothyroidism in patients at least 60 years old showed prevalence ranges of 7 to 18 percent for women and 2 to 15 percent for men.
Hypothyroidism is one of the most common endocrine diseases seen by primary care physicians.
The diagnosis is classified as overt hypothyroidism when serum TSH is elevated and free T4 is low, and subclinical hypothyroidism when TSH is high but free T4 is in the normal range. Numerous studies have shown that the prevalence of an elevated TSH is both age and gender dependent, with older women being at greatest risk. The development of MTF occurs more rapidly in individuals with a positive TAb. Diagnosis of mild thyroid failure is easy and requires a TSH measurement. If TSH is low, then measuring free T4 will determine whether the patient has MTF or overt hypothyroidism.