Subclinical thyroid dysfunction and functional capacity among elderly.
BACKGROUND
Subclinical thyroid dysfunction is common among older people and has been associated with decreased functional capacity but with conflicting data. The aim of this study was to assess the association between subclinical thyroid dysfunction and functional capacity in an elderly population.


METHODS
We included 5182 participants with a mean age of 75.2 years from the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER). Self-reported functional capacity was assessed using the Barthel Index (BI) and the Instrumental Activities of Daily Living (IADL) scores at baseline and during follow-up. Participants with subclinical hyperthyroidism (n=65) and subclinical hypothyroidism (n=173) were compared to euthyroid participants (n=4944). The association between persistent subclinical thyroid dysfunction and functional capacity and decline was also investigated.


RESULTS
At baseline, compared to euthyroid participants (BI 19.73±SE 0.06; IADL 13.52±0.02), there was no difference in functional capacity for participants with subclinical hyperthyroidism (BI 19.60±0.09; IADL 13.51±0.12, p>0.05) or subclinical hypothyroidism (BI 19.82±0.06; IADL 13.55±0.08, p>0.05). Over a mean 3.2-year follow-up period, there was no association between thyroid function and annual decline of either BI or IADL (p>0.05). No association was found between persistent subclinical thyroid dysfunction and functional capacity at baseline or during follow-up (p>0.05). Results were similar after excluding participants with a maximum BI and/or IADL score at baseline.


CONCLUSIONS
Among well-functioning community-dwelling elderly, we found no evidence that subclinical thyroid dysfunction contributes to decreased functional capacity.
1 Department of General Internal Medicine, Inselspital, University Hospital of Bern , Bern, Switzerland .
Vanessa S
VS
Virgini
Liselotte W
LW
Wijsman
Nicolas
N
Rodondi
Douglas C
DC
Bauer
Patricia M
PM
Kearney
Jacobijn
J
Gussekloo
Wendy P J
WP
den Elzen
J Wouter
JW
Jukema
Rudi G J
RG
Westendorp
Ian
I
Ford
David J
DJ
Stott
Simon P
SP
Mooijaart
D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000150:complications; D007037:Hypothyroidism / Q000150:complications; D008297:Male; D011446:Prospective Studies; D012307:Risk Factors; D013959:Thyroid Diseases / Q000150:complications*; D013961:Thyroid Gland / Q000503:physiopathology*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood
D013972:Thyrotropin; D013974:Thyroxine