Don’t think of dementia prevention as work that begins when you’re approaching retirement. That’s the one thing that Kaiser Permanente researchers Paola Gilsanz and Rachel Whitmer hope that people will realize from their study released today in the journal “Neurology.”
“People need to really appreciate the link between the health of the heart and the health of the brain,” Whitmer said.“Even though cognitive impairment and dementia are things we think about as occurring in old age or late in life, we need to think about it over the life course because what you do over your lifetime does set up your brain health for late in life.”
Whitmer, Gilsanz and several other researchers in Oakland assessed the association of early-adulthood and mid-adulthood hypertension with dementia in a diverse group of 5,646 men and women whose Kaiser health survey data were available from 1964-1973, 1978-1985 and 1996-2015.
What they found was that women who developed uncontrolled hypertension in their 40s were 73 percent more likely to suffer from dementia later in life than their female peers who did not have high blood pressure. This risk existed across all racial groups, Whitmer said, and the results were the same when adjusted for other factors that could affect a dementia diagnosis, such as smoking, diabetes and body mass index.
While the researchers could find no such linkages among male study subjects, Whitmer pointed out that hundreds of studies have shown that men and women who develop hypertension in their 50s do show increased risk of dementia later in their lives.
“Changes in the brain take decades, so there’s been a big focus in the field in the last five to eight years looking at risk factors and also protective factors from earlier in the life course,” she said. “We really think these men with hypertension, it’s not that it’s not bad for their brain, it’s just that they didn’t live long enough to get diagnosed with dementia. They were just more likely to die sooner in our follow-up.”
On a positive note, Whitmer said, people who control their hypertension and other risk factors can prevent dementia
“Let’s pretend that I’m in this study and I had hypertension in my 30s, but I got treated and in my 40s, I don’t have it,” Whitmer said. “I am not at higher risk anymore of dementia. If I had it in my 30s and I still had it in my 40s, I am at high risk.”
Alzheimer’s disease is the most common form of dementia caused by brain degeneration, but patients who have it also often exhibit signs of vascular dementia. The latter occurs when the blood supply to the brain is impaired, perhaps resulting in a series of small, often undetectable strokes.
Scientists in the field of dementia are trying to understand what happens first, whether it’s possible that one type of dementia may trigger another.
“There is data out there that, after people are diagnosed with Alzheimer’s disease,” Whitmer said, “they’re more likely to be diagnosed with stroke, but probably before their Alzheimer’s disease, they probably had some silent, small strokes that no one knew about. Both of these processes are happening in tandem.”
So what can you do to defend yourself against dementia? Whitmer said you should eat and exercise for heart health and you should screen for hypertension.
“Long-term hypertension, particularly if it’s not controlled, will affect the brain,” she said.