Screening for thyroid disease in the elderly. Serum free thyroxine and thyrotropin concentrations in a representative population of 81-year-old women and men.

Thyroid function in individuals from a representative population of 81-year olds was evaluated clinically and from assay of serum thyrotropin (TSH) and serum free thyroxine (free T4). Among the 144 men, 2 had markedly abnormal values; L-thyroxine treatment had been prescribed for both, one because of primary hypothyroidism (concentrations at screening were high for TSH and low for free T4) and one because of panhypopituitarism (low free T4 at screening). Among the 250 women, 10 had TSH concentrations greater than 10 mU/L; L-thyroxine therapy had been prescribed for 3 of them. Only 1 non-L-thyroxine treated woman had a high free T4 concentration. She had few clinical signs and symptoms of hyperthyroidism (mainly weight loss), and multinodular goiter. Total and free 3,5,3'-triiodothyronine concentrations were normal but her total and free T4 concentrations were high at ages 70, 75 and 79 years, indicating that "T4-toxicosis" had been present for at least 11 years without evidence of progression of her hyperthyroidism. The results indicate that clinical signs and symptoms of thyroid disease in the elderly may be too subtle for diagnosis.