SERUM THYROGLOBULIN IN HOSPITALIZED CHRONIC GERIATRIC-PATIENTS - ITS RELATIONSHIP TO AGE, NONTHYROIDAL ILLNESS, GOITER AND THYROID-DYSFUNCTION IN A FOLLOW-UP-STUDY

The objectives were to determine whether the serum thyroglobulin (TG) level is influenced by age or by non-thyroidal illness (NTI) of the ag ed, to investigate the constancy of the TG level after 1- and 2-month intervals and to investigate if the TG level could help to differentia te whether a subnormal thyrotrophin (TSH) level in a geriatric patient is caused by autonomous thyroid function, by age or by NTI., Two-hund red and twenty-six non-selected, chronic hospitalized patients over 60 years old and 82 healthy adults (20-40 years) participated in the stu dy, and TSH, thyroxine, free thyroxine, triiodothyronine and TG were e stimated. In 122 euthyroid geriatric patients with normal TSH the mean TG was normal (12.18 mu g/l), but elevated (> 45 mu g/l) TG values oc curred more often than in healthy control persons (15/122 vs 3/82; chi ((1))(2) = 4.54, p = 0.03). The severity of the clinical state of the euthyroid patients had no influence on the TG values. If TG was measur ed after 1 and/or 2 months, in only 3/123 non-selected geriatric patie nts was there a fluctuation between the normal and abnormal range (ver sus fluctuation of the corresponding TSH values in 19/123 cases; chi(( 1))(2) = 12.78, p = 0.0012). In 28 patients with subnormal TSH, a norm al TG value had a predictive value of 0.6 to exclude autonomous thyroi d function. Age and NTI of the geriatric patients have no significant influence on their mean TG level but high TG levels occur more often, even in euthyroid patients. The predictive value of TG is not sufficie ntly high to allow a clear differentiation of whether a subnormal TSH is caused by autonomous thyroid function or by the age process or by N TI. Nevertheless, the advantage of TG estimation to be more constant t han TSH could be of benefit in screening studies.