- New research links a genetic predisposition to certain types of high blood pressure and high cholesterol to an increased risk of developing Alzheimer’s disease.
- Researchers say these new findings can help influence the development of medications to help prevent Alzheimer’s.
- Despite the findings, experts stress that there is a range of risk factors that can lead to the development of Alzheimer’s disease.
Alzheimer’s disease impacts more than 6 million Americans and is the seventh leading cause of death in the U.S. But despite its devastating impact, there’s a lot researchers don’t know about what causes the disease. Now, a new study suggests having a family history of high blood pressure and high cholesterol may play a role.
The study, which was published in JAMA, analyzed data from 39,106 people with clinically diagnosed Alzheimer’s disease and 401,577 controls who did not have the disease. The researchers discovered that people who had certain genes that led to higher levels of HDL (“good” cholesterol) had a slightly higher chance of developing Alzheimer’s disease than those who didn’t have the genes. They also found a slight increased risk in people who had genes that can contribute to higher systolic blood pressure (the top number on a blood pressure reading).
The researchers discovered that there was a 10% increased risk for every increase in HDL cholesterol, along with a 1.2 times increase for every 10 mm/Hg increase in systolic blood pressure.
The researchers concluded that the findings suggest that HDL cholesterol and systolic blood pressure “may be involved in Alzheimer’s disease pathogenesis, which may thus inspire new drug targeting and improved early dementia prevention.”
Study co-author Ruth Frikke-Schmidt, M.D., Ph.D., a professor and chief physician in the Department of Clinical Biochemistry at the University of Copenhagen says that the goal of the study was to try to figure out modifiable risk factors for Alzheimer’s disease. “To recommend the most efficient preventive strategy, we need to pinpoint those modifiable risk factors that directly is a cause of dementia,” she says. While you can’t help your genetics, they can help “robustly” inform researchers of the direct impact of a specific risk factor. “When we have this piece of evidence, we can with more confidence recommend preventing these risk factors in occurring, or if they are already present, they should be treated as early as possible,” she explains.
But why might high levels of certain types of cholesterol and blood pressure raise your risk of Alzheimer’s disease, and what can you do about it? Experts break it down.
Why is there a link between cholesterol and blood pressure with Alzheimer’s disease?
It’s important to note this, per Amit Sachdev, M.D., M.S., medical director in the Department of Neurology at Michigan State University: “The increased risk of dementia with the presence of high blood pressure and high cholesterol is not new.” Dr. Frikke-Schmidt, agrees, noting that “high blood pressure is a well-known risk factor for bad brain health.”
But...why? “The brain has the densest, most complex vasculature of any organ in the body, filtering oxygen and nutrients through an elaborate blood brain barrier to ensure toxins do not reach the sensitive electrical network of neurons and clearing waste from the brain,” says Matthew Schrag, M.D., Ph.D., assistant professor of neurology at Vanderbilt University School of Medicine. Those toxins can build up over time, and may lead to the development of brain disease like Alzheimer’s, he says.
This isn’t the first time blood pressure has been connected with Alzheimer’s disease. “This builds on a large clinical trial from 2019 called the SPRINT-MIND study, which showed that careful blood pressure control lowered the risk of mild cognitive impairment and dementia,” Dr. Schrag says.
What experts haven’t known in the past was if high blood pressure was a direct cause of Alzheimer’s disease or simply something that is linked with the disease. “The very important novel finding from our study is that we now show that high blood pressure most likely is a direct cause of future development of Alzheimer’s disease,” Dr. Frikke-Schmidt says.
As for why higher levels of HDL cholesterol may be a contributing factor, Dr. Frikke-Schmidt says it could be due to the way HDL particles behave. “High HDL cholesterol is associated with the presence of large buoyant HDL particles that may be dysfunctional in local cholesterol transport inside the brain and across the blood-brain barrier,” Frikke-Schmidt says. “This may have implications for cholesterol supply to the brain cells and clearance of sticky waste products.”
While “the mechanisms are not fully clear,” Michal Beeri, Ph.D., director of the Herbert and Jacqueline Krieger Klein Alzheimer’s Research Center at Rutgers University, says that both risk factors can impact the body’s blood vessels and the vessels in the brain. “Healthy brain vasculature is crucial for healthy cognitive aging,” she says.
What are the other risk factors for Alzheimer’s disease?
Experts point out that high blood pressure and elevated cholesterol levels aren’t the only potential risk factors for Alzheimer’s disease. “Having a family history of a systemic illness like high blood pressure or high cholesterol does not mean that you will end up with Alzheimer’s dementia,” says David Merrill, M.D., Ph.D., a geriatric psychiatrist and director of the Pacific Neuroscience Institute’s Pacific Brain Health Center in Santa Monica, Calif. “There are literally dozens of health risk factors, including some modifiable risk factors, that can lead to an increased risk of Alzheimer’s.”
Known risk factors, according to the Centers for Disease Control and Prevention (CDC), include:
- A sedentary lifestyle
- High blood pressure
- Smoking cigarettes
- Diabetes
- Excessive alcohol use
- Depression
- Obesity
- Hearing loss
“We are in the middle of an important change of thinking in the field of neurodegenerative disorders and dementia,” Beeri says. “We are learning that, rather than having a single cause, most of these diseases result from a combination of factors, including aging, genetics, inflammation, and, importantly, blood vessel disease.”
How to lower your risk of Alzheimer’s disease
If you have a family history of high blood pressure or high cholesterol, don’t stress out. Experts suggest that there are things you can do to get these conditions under control if you happen to develop them.
“Controlling blood pressure is a promising preventative treatment for Alzheimer’s disease that is inexpensive, available to everyone, and supported by strong scientific evidence,” Beeri says. “Getting blood pressure under control can take a bit of work for some patients, but anyone can buy a reliable blood pressure cuff, regularly check your blood pressure at home, and bring those numbers to your doctor.”
Trying to maintain a healthy weight may also help bring high blood pressure down and lower the risk of Alzheimer’s disease, Dr. Frikke-Schmidt says.
The U.S. Department of Health and Human Services (HHS) recommends taking the following additional steps to lower your risk of dementia:
- Manage your blood sugar.
- Eat a good mix of fruits, vegetables, whole grains, lean meats, seafood, and unsaturated fats.
- Try to get at least 150 minutes of moderate-intensity physical activity each week.
- Keep your mind active by reading, playing board games, or learning a new skill.
- Socialize with family and friends.
- Treat hearing issues.
- Take care of your physical and mental health.
- Try to get seven to eight hours of sleep a night.
- Do your best to prevent head injuries, like wearing shoes with nonskid soles and a helmet while biking.
- Have no more than a drink a day (for women) and two drinks a day (for men).
- Avoid tobacco products.
If you have a family history of high blood pressure or high cholesterol, experts say it’s a good idea to flag that for your primary care physician so that you can be properly monitored and treated, if necessary. “Manage your overall health,” Dr. Sachdev says. “A healthy body leads to a healthy brain.”
