December 19, 2017
For those who have watched loved ones with Alzheimer’s slip away, it’s hard not to be hopeful about prevention research that shows promise. After all, there has been evidence to suggest that guzzling a few tablespoons of olive oil or adding 10,000 steps to your day could help stave off the disease. But an extensive new study on dementia prevention efforts says the opposite: Researchers found that there is no method that prevents late-life dementia proven by scientific research.
The review looked at data from dozens of studies that measured prevention methods, like over-the-counter vitamins and supplements, physical activity, prescription medicine and cognitive training. The review only included studies that used the gold standard of medical research to test whether an intervention is effective: a randomized controlled trial. That means one group was given the prevention method being studied, while a placebo or no action was given to the other group as a control.
The researchers, who conducted the analysis at the Minnesota Evidence-based Practice Center, did find “low-strength” evidence that combining different types of prevention tactics at the same time improved memory performance marginally.
The study wasn’t all doom and gloom, though. The authors did find signs that physical activity offers some protection. The reason they could not be more conclusive, they wrote, was that the studies were too small or did not last long enough “to show the true long-term effect of a physically active lifestyle.”
And while an editorial written by Dr. Eric B. Larson that accompanied the study said, “All evidence indicates that there is no magic bullet,” it also highlighted habits that promote a healthy lifestyle that may have an added benefit of preventing dementia. But, according to Larson, it’s not the simple fix that most people are looking for.
“I tell them that they can take many common-sense actions that promote health throughout life and may help to avoid or delay Alzheimer’s disease and related dementias,” he wrote.
Larson added that not smoking, engaging in regular physical activity, controlling diabetes, hypertension and cholesterol, and maintaining a healthy diet and weight might help delay dementia.
“Engaging in cognitively stimulating activities and avoiding social isolation also are probably beneﬁcial,” he added.
The study findings are at odds with a report the Lancet International Commission on Dementia Prevention released in July that concluded that about 35 percent of dementia cases are linked to modifiable risk factors: education level, smoking, high blood pressure, obesity, hearing loss, diabetes, physical inactivity, depression, and low social contact. Larson, who was also involved in that study, explained that it’s because the two studies approached what kind of studies they included differently. The Lancet study included observational studies that looked at things like education levels, medical conditions like diabetes or level of social contact. Those studies cannot be conducted like clinical trials because it would be unethical to try to control those factors.
The study is not as pessimistic as it might first seem, though. “Even under those fairly tight restrictions, the group still was able to say that there are certain modifiable factors that do have some evidence that reduce risk for Alzheimer’s disease and dementia as you age,” Keith Fargo, PhD, director of scientific programs and outreach at the Alzheimer’s Association told CBS News. “I think overall that’s a positive thing.”
Lastly, it can’t hurt to engage in prevention methods that align with a healthy lifestyle. “Note that none of these recommendations has harmful side effects,” wrote Larson.
This study was published in Annals of Internal Medicine.