It’s no surprise that old age is the biggest influence on whether you get Alzheimer’s, but you may raise an eyebrow over what can seem like an endless scroll of other potential risk factors for the deadly brain disease. After all, recent studies have tied an increased risk of dementia to breathing polluted air, drinking a daily diet soda, undergoing anesthesia, being “sleepy” in the afternoon, and, if you're a woman, to either having lots of kids or not having enough of them, depending on which set of results you believe.
For those who feel like throwing their arms up in defeat, “it’s important to remember that risk factors are just that — factors, not fate,” says Gregory Jicha, M.D., a professor at the University of Kentucky’s Sanders-Brown Center on Aging. “We see folks all the time who have done everything right and still come down with dementia, and those who do everything wrong and never have an issue. It’s not something you can completely control.”
What’s more, experts note that many studies are quite limited in scope, with findings that may be interesting or useful to an Alzheimer’s researcher — as one piece of information in a complex array of genetic and environmental factors possibly causing changes in the brain — but that aren’t meant to influence behavior on an individual level. Findings that seem eerily specific — say, how “sleepy” someone feels at 3 p.m., or how he or she responds to anesthesia — may in fact reflect larger, underlying conditions, such as how well someone sleeps in general, or how healthy he or she is before going into surgery.
That said, it is helpful to understand a smaller set of proven, significant and actionable risk factors, Jicha says. You may not be able to turn back the clock (or move to a less-polluted city, or change the number of children you had), but there is plenty you can do to protect your brain health. We asked experts to pinpoint the most important dementia risk factors — the ones you really need to focus on.
Anything that blocks or reduces blood flow in the body — a stroke, heart disease — also increases your risk for dementia. After all, your brain has a critical need for uninterrupted blood circulation, so it’s important to keep those vessels free and clear. Quit smoking, and work to get conditions that can harm your vascular health under tighter control. These can include high blood sugar, high cholesterol, obesity and, especially, high blood pressure. High blood pressure, or hypertension, is strongly associated with an increased risk of dementia — more so than any other single health condition. This may be in part because of its prevalence, says Jicha, who notes that between 70 and 80 percent of older adults have high blood pressure. “It’s also a silent risk factor that you can carry for years without realizing it,” he says. “That’s not the case for diabetes or obesity. It’s hard to run away from those conditions the way you can with high blood pressure.”
However, it’s best to talk to your doctor about your optimal blood pressure levels, says Joe Verghese, a professor at Albert Einstein College of Medicine and chief of geriatrics at the Montefiore Health System. “Blood pressure levels that require treatment in someone who is 60 are different than in someone who is 80,” he says. “The older you are, the more leeway you have in how high your blood pressure can safely be.”