Hyperthyroidism may increase dementia risk in women

by Amber Cox for Healio:

An increased risk for dementia in women was associated with higher free thyroxine levels, even in the normal range; however, no risk increase was found among men, according to recent study findings presented at the 15th International Thyroid Congress and 85th Annual Meeting of the American Thyroid Association.

Layal Chaker, an MD, PhD, student at Erasmus Medical Center in the Netherlands, and colleagues evaluated data from the Rotterdam Study on 9,495 adults (mean age, 64.9 years) to determine the relationship between thyroid function and risk for dementia and MRI-related brain structures. Mean follow-up was 7.8 years.

Researchers identified a lower risk for dementia in the full (HR = 0.9; 95% CI, 0.83-0.98) and normal (HR = 0.76; 95% CI, 0.64-0.91) range of thyroid function with higher thyroidd-stimulation hormone levels. Conversely, higher levels of free T4 were associated with a significantly higher risk for dementia (HR = 1.04; 95% CI, 1.01-1.07).

The absolute 10-year risk for dementia decreased from 6% to nearly 3% with higher TSH levels in women but not in men. Smaller parenchymal volumes, but not hippocampal volumes, were associated with higher free T4 levels in older participants.

“High thyroid function, even in the normal range, is associated with an increased relative and absolute risk of dementia in women, but not in men,” the researchers wrote. “In elderly (patients), high thyroid function is associated with smaller parenchymal volumes. These data suggest a role of thyroid function in pathways leading to dementia.”

Source: http://bit.ly/1MbQXAD