Aging can be a scary process for some people. Aside from losing some abilities or living with new restrictions, many people fear losing the memories that make them who they are. But there may be some good news on that front. Despite worries about an upcoming Alzheimer’s disease epidemic, it appears that dementia rates are going down in Europe and the United States, as much as 13% per decade over the past 3 decades, according to a study published in the journal Neurology. Researchers with the Alzheimer’s Cohorts Consortium, who authored the study, think they may know why.
Dementia Is Not a Normal Part of Aging
The consortium looked at data from 7 studies that followed over 49,000 patients older than 65 years for at least 15 years; 4,253 developed dementia. The researchers took note of the patients’ in-person examinations, genetic data and brain scans, as well as risk factors for cardiovascular disease. They then drew some conclusions as to what might cause dementia, which the National Institute on Aging explains as “… the loss of cognitive functioning—thinking, remembering, and reasoning—and behavioral abilities to such an extent that it interferes with a person’s daily life and activities.” Dementia is more common as people age, but the NIA explicitly explains that dementia is “not a normal part of aging.”
So what caused the drop in rates? “When we tried to explain this, the natural thing to think about is cardiovascular risk factors,” said Albert Hofman, MD, PhD, in an interview with Medical Daily. Dr. Hofman, one of the study’s authors, is the chair of the department of epidemiology at the Harvard T.H. Chan School of Public Health in Boston. Although it might not be as obvious to us as it is to Dr. Hofman, cardiovascular risk factors such as high blood pressure, high cholesterol and smoking, might be at play in the drop in dementia rates.
Protecting Brain Health by Protecting Your Heart
Modern medicine and a decline in the rate of smoking have been good for our cardiovascular health. People who follow recommended treatment and lifestyle changes, like quitting smoking, exercising and eating a healthy diet, can have better control of their blood pressure and cholesterol levels. This, in turn, might lead to better brain health, because these actions help preserve the delicate blood vessels inside your head.
A research letter published in 2017 in the Journal of the American Medical Association, Cardiology, explained that average total cholesterol dropped from 204mg/dL in 1999/2000 to 189mg/dL in 2013/2014, showing a steady downward trend. And the Centers for Disease Control and Prevention has reported that “current smoking has declined from 20.9% (nearly 21 of every 100 adults) in 2005 to 13.7% (nearly 14 of every 100 adults) in 2018, and the proportion of ever smokers who have quit has increased.” So, in some respects, as a population we’re getting healthier.
But getting on top of your cholesterol and blood pressure is just half the puzzle. It’s not just the numbers themselves that cause issues, Dr. Hofman explained. It’s also how much your blood pressure changes. “[T] here is always variability in blood pressure but some people have higher and others have lower,” he said. Although blood pressure is associated with lifestyle factors, such as body mass index, this variability is not studied as well. “[T]he relationship between lifestyle factors and variability is still largely unexplored although it is a focus of current research,” Dr. Hofman added.
What can I do?
Researchers don’t know when exactly people should start caring about risk factors for dementia, but likely, the earlier the better. “It’s never too late,” Dr. Hofman said. “You can always improve, but the most effective way is to do it as early as possible.” He says we can lower the risk of dementia by “treating [cardiovascular] risk factors but also looking at preventative measures, to prevent hypertension and high cholesterol.”
Is being a woman a risk factor for dementia? Looking around, it’s not unsurprising if people believe that women have a greater risk of developing dementia than men, but that doesn’t seem to be the case, according to the study. “Incidence, the risk, of new cases is very similar for men and women,” Dr. Hofman said. “Women live longer, so there are more women living with dementia than men.”
The rates are going down and women are no more at risk than men, so that’s good. But, you can do your brain a favor by trying to protect your blood vessels as much as you can. You can start by monitoring your blood pressure and cholesterol, and speaking with your doctor about lifestyle changes you may need to make to improve your overall health. As to the variability of your blood pressure, we’re all waiting for more research into other things we can do to keep our brains healthy for as long as possible.