TORONTO – Health factors considered outside the box when it comes to the risk of getting Alzheimer’s or another dementia – including whether a person’s dentures fit properly or they suffer from poor eyesight or hearing – may in fact contribute to development of the brain disorders, researchers say.
“Our study suggests that rather than just paying attention to already known risk factors for dementia, such as diabetes or heart disease, keeping up with your general health may help reduce the risk for dementia,” said principal investigator Dr. Kenneth Rockwood of Dalhousie University.
Rockwood, director of geriatric medicine research, said that an individual health issue like ill-fitting dentures does not raise the risk of dementia in those who are predisposed to the brain-destroying condition.
“We know, for example, that dentures on their own are not associated with an adverse outcome,” Rockwood said Wednesday from Halifax. “It’s just when they’re in combination with a whole bunch of other things that are wrong. That state of having many things wrong is associated with adverse outcomes.”
The research, published in this week’s edition of the journal Neurology, found that each health problem increased a person’s odds of developing dementia by 3.2 per cent, compared with people without such health issues.
The research included 7,239 people, age 65-plus and free of dementia, who took part in the Canadian Study of Health and Aging. Participants were assessed for Alzheimer’s disease and other types of dementia at five and then 10 years and asked about 19 health problems not previously reported to predict dementia.
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Those problems included arthritis, trouble hearing or seeing, denture fit, chest or skin problems, stomach or bladder troubles, sinus issues, broken bones and feet or ankle conditions, among others.
After 10 years, almost 3,000 had died, about 880 were cognitively healthy, while more than 600 had Alzheimer’s disease or another dementia. Close to 700 had cognitive problems but no dementia, and the cognitive status of the roughly 1,000 other subjects was not clear.
The results showed that older people without health problems at initial assessment had an 18 per cent chance of developing dementia in 10 years, while the risk rose to 30 per cent for those with eight health problems, and 40 per cent among those with 12.
“The point is that anything that’s bad for you is ultimately bad for your brain,” explained Rockwood. “And in someone so predisposed, the cumulative effect of that is likely to increase the dementia risk.”
That’s because the brain and body are intimately interconnected – so any physical health problem can affect the cognitive organ.
“Our work joins a body of work that shows the brain is not an innocent bystander,” he said. “The brain fights back.”
That defensive healing mechanism – what Rockwood calls an “aberrant repair process” – is believed to set in motion an immune inflammatory response that might possibly result in the tangled brain plaques and other neuron-destroying effects seen in Alzheimer’s.
The ability of the brain to rewire its circuitry to overcome deficits – for instance, developing a new speech pathway after a stroke – is also part of this repair process, he said.
“So people with poor neurocompensation and more harmful than good neuroinflammatory response will be at the greatest risk (of developing dementia).”
In an accompanying editorial, Dr. Jean Francois Dartigues of the National Institute of Health and Medical Research in Paris said more research needs to be done to confirm whether these non-traditional health problems may indeed be linked to an increased risk of dementia.
“But if confirmed, the consequences of these findings could be significant and could lead to the development of preventive or curative strategies for Alzheimer’s disease,” Dartigues wrote.