Alzheimer's more aggressive in the younger elderly: study

Researchers at the University of California, San Diego, in a study of 723 older people found that those in their 60s and 70s lost their mental sharpness quicker and brain mass faster than those in their 80s and 90s, The Telegraph reported.

"It could be that people diagnosed with Alzheimer's at an older age had brains with a higher degree of "cognitive reserve". This essentially means their brains are fitter and more resilient due to having been exercised more during their lives," Linda EcEvoy, co-author of the study said.

A second theory is that older patients could be suffering from Alzheimer's for years, and only display symptoms when another form of dementia strikes.

"These findings challenge the misconception that Alzheimer's and dementia is only a problem for much older people, suggesting it may be more aggressive in people in their 60s and 70s," Dr Simon Ridley, head of research at Alzheimer's Research UK, was quoted by the paper as saying.

The study was published in the journal PLoS One.