Thyroid function, morphology and prevalence of thyroid disease in a population-based study of Danish centenarians.
OBJECTIVE
To investigate thyroid function, morphology, and autoimmunity in relation to physical function in an unselected population of centenarians.


METHODS
A population-based survey.


METHODS
Denmark.


METHODS
All persons living in Denmark who celebrated their 100th anniversary during the period April 1, 1995 to May 31, 1996, a total of 276 persons.


METHODS
Thyroid hormones (TSH, T4, FT4I, T3, FT3I, and T3RU), thyroid autoantibodies (TPOab and Tgab), thyroid volume, activities of daily living according to the Katz Index of ADL.


RESULTS
In all, 207 (75%) of the 276 eligible subjects participated, and 148 agreed to blood tests. Among the participants, 2.9% had previously known hyperthyroidism, and the same proportion had previously known hypothyroidism. The blood tests did not reveal any undiagnosed cases of overt thyroid dysfunction. However 7.2% had a subnormal serum TSH, and 2.9% had an elevated serum TSH; all had normal serum T3 and serum T4 levels. Thyroid autoantibodies were detected in 26 (17.6%) centenarians (11.5% had Tgab and 9.5% had TPOab). Among relatively independent centenarians, low serum T3 was significantly associated with high comorbidity (P = .029), whereas both low serum T3 and thyroid autoantibodies were significantly associated with ADL-dependency (P < .001 and P = .030, respectively). Ultrasonography (n = 50) revealed a small gland with a median volume of 8.3 mL (range 3.2-27.9) compared with an expected volume of 20 mL (14-26) (P < .001). There was no significant relationship to body weight. When examined by ultrasound, only 26% had significant morphological alterations.


CONCLUSIONS
Thyroid dysfunction does not seem to be more prevalent among centenarians than among younger old people. Low serum T3 is related to poor physical function and co-morbidity, whereas thyroid autoimmunity is related only to poor physical functioning. Despite atrophy of the thyroid gland, these findings suggest that thyroid function is well preserved in centenarians.
Andersen-Ranberg
K
K
Aging Research Center, Odense University, and Department of Geriatrics G, Odense University Hospital, Denmark.
Jeune
B
B
Høier-Madsen
M
M
Hegedüs
L
L
D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000097:blood*; D016009:Chi-Square Distribution; D015897:Comorbidity; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence; D018709:Statistics, Nonparametric; D013959:Thyroid Diseases / Q000097:blood / Q000453:epidemiology*; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000000981:diagnostic imaging / Q000276:immunology / Q000503:physiopathology*; D013963:Thyroid Hormones / Q000097:blood*; D014463:Ultrasonography
D001323:Autoantibodies; D013963:Thyroid Hormones