Low Testosterone Associated with Increased Dementia Risk
Low levels of total and bioavailable testosterone may be associated with an increased risk of dementia in elderly men, according to French investigators.
From a cohort of 3,650 men aged 65 years and older, Laure Carcaillon, MD, of Inserm in Villejuif, France, and collaborators compared 105 men with incident dementia and a random sample of 413 men without dementia. The median follow-up period was 3.1 years. Compared with the middle tertile of total testosterone (total-T) level, the lower and upper tertiles were associated with a 2.3 times and 1.9 times increased risk of dementia, respectively. Low bioavailable testosterone (bio-T) also was associated with a greater risk for dementia, especially among men aged 80 years and older, investigators reported online ahead of print in Alzheimer's & Dementia. In men aged 80 and older, low bio-T was associated with a significant threefold increased risk of dementia; in men younger than 80, it was associated with a nonsignificant 7% increased risk.
Additionally, the risk of dementia associated with low bio-T was greater in men with a high level of education compared with men who had a low level of education.
Taken together, the authors noted, their results support the hypothesis of a deleterious effect of low testosterone concentrations on brain aging, and also suggest that high levels of total-T could increase this risk.