The preventive steps with the greatest impact are mentally stimulating activities, which include reading and chess; avoiding stress, depression and head trauma; and avoid diabetes, high blood pressure, and weight gain in middle age and beyond, according to a meta-analysis published Monday.
Regular physical exercise, quality sleep, not smoking, maintaining good heart health in old age, and including vitamin C in the diet are among the nine preventive actions with slightly weaker but still supportive evidence.
“If risk factors can be modified, the evidence suggests that at least one in three cases of Alzheimer’s can be prevented,” said neurologist Dr. Richard Isaacson, director of the Alzheimer’s Prevention Clinic at Weill Cornell Medicine.
“People can take different paths to Alzheimer’s disease,” said Isaacson, who was not involved in the study. “This document helps provide an evidence-based framework for physicians and patients to consider when managing a person’s Alzheimer’s risk.”
The study published in the Journal of Neurology, Neurosurgery & Psychiatry.
First-class prevention
Two thirds of the most promising interventions focused on healthy lifestyle changes and risk factors for cardiovascular disease, such as high blood pressure and cholesterol levels.
The study analyzed 395 prospective observational studies and randomized controlled trials. These efforts, according to the researchers, were the “most comprehensive and large-scale systematic review and meta-analyzes for Alzheimer’s disease to date.”
The top 10 science-backed preventive actions the study found included:
- Keep blood sugar and weight under control to avoid diabetes.
- Maintain weight at a healthy level, generally below a body mass index (BMI) of 25
- Get as much education as possible in early life
- Avoid head trauma (such as concussions)
- Stay cognitively active by reading and learning new things
- Avoid or control depression.
- Managing bad stress that raises cortisol levels
- Treatment of “orthostatic hypotension” when you regularly feel dizzy or light-headed when you stand up while sitting
- Keeping blood pressure under control in middle age
- Avoid high levels of homocysteine, an amino acid that can contribute to the formation of blood clots in blood vessels and arterial damage.
“One of the most important and commonly ignored modifiable factors is a high level of homocysteine in the blood,” said Isaacson. At his New York-based preventive clinic, he said he will often suggest B-complex vitamins to combat elevated homocysteine levels.
“However, previous research has shown that vitamin B supplementation ‘works’ better if these people also have sufficient levels of Omega3, which are brain-healthy fats found in fatty fish, for example,” Isaacson explained.
“So this is just one of many examples of the complex decision-making network that goes into the clinical care of people at risk for the disease.”
Other positive measures.
Nine actions that had weaker, but still positive, impacts to reduce the risk of developing Alzheimer’s were:
- Get regular physical exercise
- Eliminate obesity in middle age
- Avoid weight loss at the end of life
- Don’t smoke and avoid secondhand smoke.
- Get enough good quality sleep
- Avoid cerebrovascular diseases, which include strokes and diseases that affect blood flow in the brain
- Avoid frailty in adulthood
- Control atrial fibrillation, which is a fast and irregular heart rate due to chaotic electrical signals in the heart
- Eating foods with vitamin C or taking supplements
Of the 21 study recommendations, the last two were actions that physicians should avoid when working with patients at risk for Alzheimer’s disease. Strong evidence was found against estrogen administration to postmenopausal women to improve cognition.
“I totally agree with this statement, but for women in perimenopause and early menopause, hormone replacement therapy can sometimes be considered based on a variety of other factors,” said Isaacson.
Finally, weaker evidence indicated that acetylcholinesterase inhibitors, drugs like donepezil and galantamine, which are often prescribed to treat memory loss in people with diagnosed Alzheimer’s disease, should not be used as a preventive tactic.
“Those are drugs for symptomatic people with mild dementia or worse,” said Isaacson. “Those drugs work for symptoms but don’t slow the progression of the disease.”
People who are concerned about their risk of developing Alzheimer’s should work with a trained doctor in the field to develop an individualized plan to reduce their risk, Isaacson said.
“It is also important to note that there is no single ‘magic pill’ or action that can prevent Alzheimer’s,” he said.
“Risk reduction care is not ‘one size fits all’; it must be comprehensive and personalized, ideally under the supervision of a physician.”
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