Hypothyroidism is not associated with decreased
performance of daily activities or increased mortality in old age
(March 2005)
The background of the study. Thyroid dysfunction
is common among older people, but its clinical consequences are
uncertain. In this study, thyroid function, performance of activities
of daily living, and cognitive function were assessed in a group
of elderly subjects.
How the study was done. The study subjects were
85-year-old residents of Leiden, the Netherlands. Plasma thyrotropin
(TSH) and free thyroxine (T4) were measured at base line, and performance
of activities of daily living and cognitive function were assessed
at that time and then annually for four years.
The results of the study. Initially, there were
558 subjects (369 women and 189 men), of whom 82 percent were living
independently, 82 percent were independent in personal activities
of daily living, and 69 percent had good cognitive function. Eighty-five
percent had normal thyroid function, 12 percent had hypothyroidism,
and 3 percent had hyperthyroidism.
There was no correlation between plasma TSH and free T4 values
and any of the performance measures or cognitive function at base
line. All performance measures decreased during follow-up. Higher
initial plasma TSH concentrations were not associated with a more
rapid decrease in performance or cognitive function during the study.
In both women and men, mortality from all causes and from cardiovascular
and noncardiovascular causes was lower during follow-up in those
with higher plasma TSH and lower plasma free T4 concentration at
base line.
The conclusions of the study. Among 85-year-old
subjects, hypothyroidism is not associated with deterioration of
the ability to perform activities of daily living, deterioration
of cognitive function, or increased mortality.
The original article. Gussekloo J, van Exel E,
de Craen AJ, Meinders AE, Frolich M, Westendorp RG. Thyroid status,
disability and cognitive function, and survival in old age. JAMA
2004;292:2591-9.
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