Because adopting a healthy lifestyle could help you...
Over the years, research allowed specialists to pinpoint what are the risk factors associated with Alzheimer's disease.
While some cases are directly linked to a genetic susceptibility, others will originate from environmental factors, including one's lifestyle.
That said, the disease is a multifactorial disorder, meaning that it comes from the interplay of genetic and environmental factors. Changes in the brain will emerge months, if not years, prior to the first symptoms.
Dementia is not an unavoidable consequence of aging. However, the odds of living with it grow with time.
About 95% of all Alzheimer disease cases have a late onset, starting at, or after 65 years old.
Early-onset Alzheimer's disease accounts for 5 % of all cases. Most are familial-related, meaning that they are caused by a genetic mutation. The genes coding for amyloid precursor protein (APP), presenilin 1 (PSEN1) and presenilin 2 (PSEN2) are the common suspects.
Other genes have been associated with a higher susceptibility to develop the disorder, such as the apolipoprotein E (APOE) gene.
People with a higher education level have a reduced probability to develop Alzheimer's disease. Cognitive or mentally stimulating activities such as reading, crosswording, doing puzzles or playing games have also been associated with a reduced risk.
It is also true for socially engaged individuals who maintain a social rich network.
Mentally and socially stimulating activities act as compensatory factors. They are associated with a higher density of brain connections and an increased ability to use brain networks, even in the presence of a pathology like Alzheimer disease.
The brain needs a continuous blood flow in order to function properly. Impairment of that flow increases the odds of developing the disease.
For instance, people living with diabetes since their middle age have a 50 % increased risk to develop Alzheimer.
On their side, smokers increase their risk by 50 to 80 %.
Hypertension, high cholesterol and obesity are also associated with a higher probability to develop the disease.
Living concurrently with multiple cardiovascular risk factors in the middle age increases the odds of developping Alzheimer's disease compared to someone facing only one of those risks.
On another note, people who practise a regular physical activity throughout their life, even a low-intensity one such as walking, reduce their risk by around 40 %.
Light to moderate alcohol consumption is also associated with a 30 to 40 % reduced risk to develop the disease.
Traumatic brain injuries
A history of head injuries is associated with an early onset of dementia and Alzheimer's disease. Autopsy studies have revelled the presence of amyloid depositions in 30 % of people who died shortly after a brain injury.
Athletes practising a contact sport like boxing, American football or hockey can sometimes develop chronic traumatic encephalopathy later in their life. They also constitute a group that at risk for dementia.