Prevalence of thyroid dysfunction in elderly subjects from the general population in an iodine deficiency area

The prevalence of thyroid disorders was investigated in 466 (403 female, 63 male) subjects over the age of 60 years (79.2 ± 7.5 years; \({/bar x}\) ± SD) from the general population in an area of iodine deficiency. In addition to thyroid hormone assays, thyroid antibodies and urinary iodine excretion were determined. In cases with thyroid dysfunction, ultrasound investigations were performed. p]Twenty-two of the 466 subjects (4.7%) showed hyper- or hypothyroidism; 7 subjects were hyperthyroid (1.5%), 5 had primary hypothyroidism (1.1%), and 10 showed “subclinical” hypothyroidism (2.2%). The latter constellation is defined as an elevation of thyrotropin (TSH) with normal values for thyroxine and triiodothyronine. Most subjects with hyperthyroidism had a goiter by palpation (6/7); thyroid volume by ultrasound (median) was 26.2 mL with an inhomogeneous echo pattern in 6 of the 7 subjects. In 4 cases, a rise in urinary iodine excretion was documented; none had TSH-receptor antibodies. Most subjects with overt or subclinical hypothyroidism had a homogeneous or low-echogenic pattern by ultrasound; thyroid volume (median) was 12.9 mL and 12.7 mL, respectively. By palpation, 8 of the 15 subjects had no goiter. In general, these persons had no rise in urinary iodine excretion (11/13), but most showed an elevation of antibodies against the microsomal antigen and/or thyroglobulin (11/15). In summary, thyroid disorders in the elderly are not rare. In most cases with hyperthyroidism, an iodine contamination in subjects with a long-standing goiter seems to have a pathogenetic effect. Hypothyroidism seems to be caused mainly by autoimmune mechanisms. (Aging 3: 325-331, 1991)