The link between some health conditions, such as anxiety, and an increased risk of developing Alzheimer’s disease has been established before.
But new research from Melbourne’s Florey Institute has revealed some conditions are actually associated with a lower risk of dementia later in life.
The groundbreaking study analysed health data from 2,443 older Australians who are part of the Australian Imaging, Biomarker and Lifestyle study, a large-scale, long-term look at ageing and dementia.
The researchers were looking for any associations between 20 comorbidities and increased incidences of Alzheimer in old age.
Dr Nicholas Pan, lead author of the study, says the research provides a useful insight into the complex interconnections between the many conditions most people with Alzheimer’s disease are also suffering from.
“This is the first study to assess 20 comorbidity associations with cognitive impairment using a single Australian dataset, which allowed us to fully consider how these conditions affect the likelihood of developing Alzheimer’s disease.
Perhaps unsurprisingly, the team found a strong association between anxiety and other neurological disorders and Alzheimer’s. Dr Pan says people who suffer these disorders earlier in life are over-represented in Alzheimer’s figures later in life.
“People with anxiety and neurological disorders are 1.5 and 2.5 times more likely to have Alzheimer’s disease,” he says.
“For people with anxiety, males have higher odds than females of developing Alzheimer’s disease.”
But fascinatingly, Dr Pan’s team found many prior health conditions – including arthritis, cancer, gastric complaints and high cholesterol, joint replacement, visual defect, as well as kidney and liver disease – were actually associated with lower incidences of Alzheimer’s disease.
How does that work?
With such a varied group of conditions, Dr Pan says further research is needed into why these specific comorbidities would decrease your Alzheimer’s risk.
“We need further research to understand whether these diseases interfere with the evolution of Alzheimer’s or whether there might be other reasons,” he says.
“The medications or treatments used for these diseases may possibly contribute to this observation. Our study indicates a new opportunity for biologists to study the links between these 20 conditions with Alzheimer’s disease.”
At least in the case of cancer, Dr Pan says the relationship may be due to a protein known as p53. In Alzheimer’s patients, a deformed version of p53 accelerates the amyloid-beta mediated neuron death typically seen.
But cancer is known to supress p53 and inhibit its functioning, which could be the link between the two diseases.
Interestingly, despite anxiety being strongly associated with Alzheimer’s, the team found no strong link in the case of depression.
Another surprising result was the fact that the team found no link between previous strokes and Alzheimer’s, despite strokes being listed as a known risk factor by many dementia support societies.
Is there a history of Alzheimer’s in your family? Do you suffer from any of these other conditions? Let us know in the comments section below.
Also read: Australians don’t know enough about dementia
