Thyroid hormones closely related to cognition in adults
Results from a cross-sectional analysis conducted by researchers at the NIH indicate that cognition is associated with thyroid hormones in adults, but vary by sex, race and depressive status.
Using data from the Healthy Aging in Neighborhoods of Diversity Across the Life Span (HANDLS) study, May A. Beydoun, PhD, of the National Institute on Aging, and colleagues analyzed the relationship between thyroid hormones and cognitive function. HANDLS examined the results of 13 cognitive tests given to 1,275 to 1,346 adults (aged 30 to 64 years) in Baltimore between 2004 and 2009. Beydoun and colleagues used baseline data from HANDLS.
The tests evaluated areas of learning/memory, language/verbal, attention, visuo-spatial/visuo-construction, psychomotor speed, executive function and mental status among men and women.
According to data, increased free thyroxine levels were linked to better performance on visuo-spatial/visuo-construction ability tests and learning/memory tests among women and blacks, after adjusting for reference ranges and Bonferroni corrections. Additionally, higher total T4 levels were associated with better psychomotor speed performances, and higher levels of free T4 and total T4 were associated with better language/verbal test performance in men.
Conversely, higher triiodothyronine uptake was linked to better performance on tests of visuo-spatial/visuo-construction ability and psychomotor speed among white patients.
Better performance areas of psychomotor speed and attention were attributed to levels being below the normal thyroid-stimulating hormone range (P<.004), according to data. Moreover, free T4 within the reference range was linked to better performance in the visuo-spatial/visuo-construction ability and psychomotor speed, researchers wrote.
Beydoun and colleagues wrote that these findings indicate thyroid function and cognition are related based on sex, race and depressive status.
“We also detected different associations between thyroid hormones and cognitive domains when individuals were within hormone reference ranges as opposed to when they were outside of it,” the researchers wrote. “These differences should be further evaluated.”
Disclosure: The researchers report no relevant financial disclosures.