Alzheimer’s Prevention Research
After reviewing and analyzing available studies on Alzheimer’s disease, researchers have published the first evidence-based guidelines to prevent the disease. The document includes 21 recommendations based on risk factors found in the study review. (1, 2)
Lead author Jin-Tai Yu, MD, PhD told Medscape Medical News, “The first evidence-based guideline is proposed, offering clinicians and stakeholders current guidance for the prevention of Alzheimer’s disease.” Yu is a professor of neurology at Fudan University in Shanghai, China. (2)
In their study, the researchers note that there has been a decrease in the prevalence of dementia. This downtrend has been associated with earlier investments in the population, such as improved education and vascular health. These improvements underscore the need for primary prevention, researchers said. (1)
The researchers also note that there have been worldwide efforts over the past few decades to learn more about how to prevent Alzheimer’s disease. Alzheimer’s is responsible for around two-thirds of dementia cases. And it affects 20% of people over 80 years old. (1)
However, it has been difficult to come to a verdict from the available research. The studies are marked by inconsistent conclusions and a wide variety of study designs, casting doubts on some of their credibility. (1)
There have not been evidence-based guidelines for preventing Alzheimer’s so far. So the research team decided to wade through the existing evidence to create some. (1, 2)
“More and more evidence has shown that Alzheimer’s disease, like other common chronic diseases, could be preventable as a result of increasing levels of education and improved control of relative modifiable risk factors,” Yu told Medscape Medical News. (2)
Research Process
The research team pulled Alzheimer’s-related studies from PubMed, EMBASE, and CENTRAL databases. They focused on two types of studies: observational prospective studies (OPSs) and randomized control trials (RCTs). After applying exclusion criteria, they worked with 243 OPSs and 153 RCTs. (1)
They evaluated the quality of the studies using a risk of bias tool. Researchers summarized levels of evidence to represent the quality of scientific evidence as Level A, Level B, or Level C. They then separated the recommendations into three classes after weighing the benefits of specific interventions against their risks: Class I (strong recommendation), Class II (weak recommendation) and Class III (not recommended). (1)
Alzheimer’s Prevention Guidelines
Through this research method, the research team found 104 modifiable risk factors and 11 interventions for dementia. When they were classified based on evidence quality and intervention strength, they found 21 evidence-based suggestions for the primary prevention of Alzheimer’s disease. (1, 2)
There were 10 risk factors with Level A evidence and Class I strength of recommendation. They were: (1, 2)
- cognitive activity
- hyperhomocysteinemia
- increased BMI in late life
- depression
- stress
- diabetes
- head trauma
- hypertension in midlife
- orthostatic hypotension
- education
There were also nine Class I factors with Level B evidence. They were: (1, 2)
- obesity in midlife
- weight loss in late life
- physical exercise
- smoking
- sleep
- cardiovascular disease
- frailty
- atrial fibrillation
- vitamin C
The two factors that researchers categorized as Class III (not recommended), estrogen replacement therapy and acetylcholinesterase inhibitors, challenge conventional wisdom about Alzheimer’s prevention. The medical community previously connected the higher incidence of Alzheimer’s in women with menopause. But Yu said that “our study finds that estrogen replacement therapy does not reduce the risk of Alzheimer’s disease,” and a long course of estrogen replacement therapy could actually increase the risk. (1, 2)
Some have also previously thought that acetylcholinesterase inhibitors (ACIs) could help prevent Alzheimer’s disease. But this study showed that is not the case. (1, 2)
Yu said that the best way to steer clear of many Alzheimer’s risk factors is to maintain a healthy lifestyle. Specifically, that means education, regular physical exercise, maintaining a healthy BMI, getting enough vitamin C, not smoking, and having high-quality sleep in early life. (2)
Continued Research Necessary
The study’s authors are open about its limitations. More research is needed to strengthen this study’s findings, but the guidelines are a good start in helping to prevent dementia. (1, 2)
Yi Tang, MD, PhD, who was not an author of the study, commented on its findings to Medscape Medical News. He said, “With these evidence-based suggestions, clinicians could provide a comprehensive framework of preventive strategies for Alzheimer’s disease in individuals with family history of dementia or at increased risk of cognitive decline. It’s almost impossible to prevent dementia if we only focus on one or several risk factors.” (1, 2)
