Thyroid Research Thyroid Research Archive Thyroid Disease
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.