Stable Medical Illness May Protect Aging Brain

April 24, 2006

SAN DIEGO (Reuters Health) Apr 06 - Well-controlled chronic medical illness

seems to protect elderly individuals from becoming demented as they age, new

study results suggest.

" Low levels of chronic stress (from treated medical illness) may be

physiologically beneficial for healthy brain aging, " Dr. Kaye

proposed in a poster session presented at the American Academy of

Neurology's 58th Annual Meeting in San Diego.

" There are some people who reach advanced old age and aren't demented, and

we wondered, how could that be? " Dr. Kaye told Reuters Health. " So years ago

we identified people with no common medical illness, which is fairly unusual

at this age, figuring that they would be protected from dementia. "

Dr. Kaye, from the Oregon Health and Science University in Portland, and his

associates conducted a longitudinal study comparing subjects 85 years of age

or older without common medical illnesses (NCMI, n = 123) and those with

stable common medical illnesses, such as hypertension or heart disease (CMI,

n = 162).

The data were adjusted for age, gender, Mini-Mental State Exam scores at

baseline, education, socioeconomic status and chronic illness rating. The

presence of the apolipoprotein epsilon-4 proportion and brain volume,

determined by MRI, were also considered. " We still found that chronic

controlled medical illness was protective, " the researcher said.

Specifically, they observed a 40%-reduction of risk of dementia in the CMI

group total compared with the NCMI group (p = 0.0001). Overall survival was

roughly the same in the two groups.

" Because this seemed like such a paradoxical finding, we independently had a

statistician not associated with the project run the numbers, and they came

out the same, " Dr. Kaye noted.

" So it appears that a low level of disease burden or stress to the system

may be a type of preconditioning that is necessary for more successful

aging, " he added. However, he doesn't recommend that people should try to

become ill to avoid dementia, he joked.

Physicians should stress to their patients that it's important -- even at

age 85 -- to take care of risk factors for cardiovascular disease and other

chronic illnesses, because that may be a way to maintain brain health for as

long as the patient has left. "

" We're excited about trying to tease out further how chronic illness

protects the brain, " he added, " I think there's too much emphasis on trying

to figure out why people get demented as opposed to why people don't. "

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