Higher levels of estrogen are associated with an increased risk of cognitive decline and Alzheimer’s disease in older men, according to a report from the Netherlands.

Men normally have some estrogen, albeit at levels usually much lower than in women. Previous reports have tied estrogen therapy with cognitive decline in women, but it was unclear if high levels of natural estrogen would have a similar effect in men, researchers note in the Annals of Neurology for July 24.

To investigate, Dr. Mirjam Geerlings, from the University Medical Center Utrecht, and colleagues evaluated hormone levels and cognitive function in 2974 older men who were followed, on average, for 6 years as part of the Honolulu-Asia Aging Study.

During follow-up, 134 men developed Alzheimer’s disease and 44 men developed another type of dementia, the report indicates.

With increasing levels of estrogen, the risk of Alzheimer’s disease rose, the team found. In addition, men with higher estrogen levels scored a few points lower on a standard cognitive function test than those with the lowest levels.

By contrast, testosterone levels seemed to have no impact on mental functioning. Overall, the results suggest that contrary to other reports, androgen replacement therapy would not help prevent cognitive decline in healthy men.

SOURCE: Annals of Neurology, July 24, 2006.