Circulating thyroid autoantibodies in a sample of Italian octo-nonagenarians: Relationship to age, sex, disability, and lipid profile

Circulating thyroid autoantibodies were assessed in a sample of Italian oct o-nonagenarians living in a restricted area (Val Vibrata, Abruzzo), and sel ected according to the absence or presence of chronic illness and disabilit y. The study groups included: Group A ("Successful aging"), 98 free-living healthy, fully independent, octo-nonagenarians (57 males and 41 females, av erage age+/-SD 83.9+/-3 years); Group B ("Unsuccessful aging"), 62 highly d isabled octo-nonagenarians (24 males and 38 females; average age 86.5+/-3.4 years), and Group C (Controls), 91 randomly selected healthy adult control s (42 males and 49 females; age 53.7+/-16.6 SD years, range 20-70). Serum a utoantibodies to thyroglobulin (anti-Tg) and to thyroid peroxidase (anti-TP O) were measured by passive hemagglutination and radioimmunoassays (RIA); s erum free thyroxine and thyrotropin by RIA. The prevalence of positive thyr oid autoantibody tests was not significantly increased in the elderly group s compared to the controls, with the remarkable exception of anti-Tg detect ed by RIA which were increased in disabled elderly, compared to free-living elderly and controls. Two/62 disabled elderly had subclinical (1) or mild (1) primary hypothyroidism, and one free-living woman aged 90 years was hyp erthyroid (toxic nodular goiter). No correlation teas found between serum t hyroid autoantibodies, thyroid hormones and TSH and serum lipoprotein fract ions. The higher prevalence of thyroid autoantibodies found only in disable d, but not in free-living Italian octo-nonagenarians suggests that thyroid autoimmune phenomena in the elderly may be an expression of age-associated disease rather than related to the aging process in itself. (Aging Clin, Ex p. Res. 11: 362-366, 1999) (C)1999. Editrice Kurtis.