Screening for thyroid disease in the elderly. Serum concentrations of thyrotropin and 3,5,3'-triiodothyronine in a representative population of 79-year-old women and men.

Thyroid function in individuals from a representative population of 79-year-olds was evaluated clinically and from measurements of serum thyrotropin (TSH) and 3,5,3'-triiodothyronine (T3). High TSH concentrations (greater than or equal to 10 mU/l) were found in 16 of 320 women (5%) and 2 of 204 men (1%). Signs and symptoms which traditionally are regarded as related to hypothyroidism were as common in subjects with high TSH concentration as in the remaining population and occurred in 10-50% of the subjects. In the 16 women with high TSH, free thyroxine (free T4) concentrations were low in 10, whereas only one subject had low thyroxine (T4) and T3 concentrations, indicating that free T4 is a more sensitive parameter for thyroid hypofunction in the elderly. Based on the T3 assay, there was no evidence for hyperthyroidism in this population. The results indicate that high TSH concentrations are common in elderly women, less common in men. The results show that classical symptoms of thyroid dysfunction are quite common in 79-year-olds, but do not correlate with biochemical indicators of thyroid dysfunction, indicating that defining "clinically euthyroid" in an elderly may be almost impossible.