Alzheimer's disease affects nearly 5 million Americans, a number that's expected to balloon to 13.8 million by 2050.
In its mildest form, the neurodegenerative condition is characterised by symptoms including memory lapses, getting lost, repeating questions, and misplacing things - behaviours that generally get more severe over time.
There's still a lot we don't know about the causes of Alzheimer's, but there are some factors associated with an increased risk of getting the disease. For the most part, though, an increased risk doesn't mean a person will necessarily get the disease - just that the chances are higher.
Here's what the science has to say about the factors that influence your risk of Alzheimer's and cognitive decline.
There are some risk factors that you can't control. Such is the case with age.
Every five years after the age of 65, a person's risk of developing the Alzheimer's doubles, according to the National Institute on Aging.
Genetic mutations are becoming increasingly important as a way to understand how Alzheimer's develops, both in late-onset and early-onset.
In the case of early-onset Alzheimer's, in which symptoms start showing in a person's 30s, 40s, or 50s, the disease is caused by genetic mutations in one of three genes that are inherited from a parent, according to the NIA.
There is not a known mutation that causes the late-onset disease, but there are some gene mutations that increase - and others that decrease - your risk.
You can find out more about the genetics of early and late onset Alzheimer's here.
3. Family history
While genetics can play a role, so might the environment that surrounds your family, according to the Alzheimer's Association. The organisation noted that risk of Alzheimer's increases if more than one family member has the disease.
When it comes to how genetics and a person's environment relate to their risk of Alzheimer's, there's still a lot more research that needs to be done.
4. Heart conditions
Unlike genetics and age, there are some risk factors you have some control over.
For example, managing other health conditions - diabetes and heart conditions such as high blood pressure, heart disease, stroke, and high cholesterol - may increase a person's risk of Alzheimer's disease, according to the NIA.
More research is needed to understand these risk factors, and some clinical trials are already underway, but it the connections bolster the idea that what's good for your heart could also be good for your head.
5. Head trauma
According to the Alzheimer's Association, trauma to the head is potentially associated with an increased risk of the disease down the line. That's based in part on observational research involving veterans from World War II.
Those who had either moderate or severe brain injuries during their military service were found to have an increased risk of developing Alzheimer's disease or dementia later in life.
Of course, the researchers noted, there could be other factors not taken into account in the study that might have influenced that association.
The AA recommends using helmets, wearing seat belts, and "fall-proofing" your home to decrease your chances of getting a serious brain injury.
A few lifestyle choices can also contribute to your risk of Alzheimer's. According to the World Health Organisation, smoking is associated with an increased risk of dementia and Alzheimer's.
Researchers think this has to do with the vessels that carry blood around our body and to our brains, which are also involved in things like stroke and heart disease.
Diet, exercise, social activity, and more have been all linked with decreased risk of Alzheimer's and cognitive decline. In fact, there are several surprisingly easy ways you can lower your chances of getting the disease.
This article was originally published by Business Insider.
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