1. A documented 33% dementia chance post-stroke from an Australian study? May 2012.
2. Then this study came out and seems to have a range from 17-66%. December 2013.
3. A 20% chance in this research. July 2013.
NASEM Report Offers Some Hope for Dementia Prevention Evidence for three strategies only modest, but sufficient to talk to patients
They are: cognitive training, blood pressure management in those with hypertension, and increased physical activity.
In a companion report released in March, the Agency for Healthcare Research and Quality (AHRQ) said it doesn't support a public health campaign encouraging adoption of these practices at this time.
But the NASEM report says physicians should tell patients about the potential benefits of these strategies for preventing cognitive decline, mild cognitive impairment, dementia, and Alzheimer's disease, while being sure to point out their limitations.
"Even though clinical trials have not conclusively supported the three interventions discussed in our report, the evidence is strong enough to suggest the public should at least have access to these results to help inform their decisions about how they can invest their time and resources to maintain brain health with aging," Alan Leshner, chair of the NASEM Committee on Preventing Dementia and Cognitive Impairment, said in a statement. The committee included other top names in cognitive health, including Ralph Sacco, MD, Kristine Yaffe, MD, and Ron Petersen, MD, PhD.
"We're all urgently seeking ways to prevent dementia and cognitive decline with age, but we must consider the strength of evidence -- or lack thereof -- in making decisions about personal and public investments in prevention," NIA Director Richard Hodes, MD, said in a statement.
It's a different direction from a 2010 report in which the AHRQ and NIH indicated there was insufficient evidence to make any recommendations about dementia prevention. However, more studies have been completed since then, so NIA commissioned the updated review.
The evidence for blood pressure management -- especially during midlife -- is encouraging but inconclusive. Increased physical activity has a bit more evidence behind it, much from randomized controlled trials, but the results haven't been consistently positive. Still, the committee decided that the weight of the evidence justified communicating with the public on these strategies.
The recommendation about cognitive training was based largely on results of the large-scale, long-term, NIA-funded ACTIVE study, which provided moderate strength evidence that cognitive training can improve function in various cognitive domains (reasoning and problem solving, memory, and "speed of processing") at 2 years, though the evidence became low-strength at 5 and 10 years.
The report notes that cognitive training refers to "a broad set of interventions" that "may or may not be computer based." These can include "learning a new language and increasing proficiency in daily activities such as playing bridge and doing crossword puzzles."
Many clinicians have adopted a skeptical stance against computer-based "brain games," especially after Lumosity was slammed with a $2-million fine for deceptive advertising. Indeed, even the software used in the ACTIVE trial -- now called BrainHQ, by Posit Sciences -- was originally developed in academia but later sold to the for-profit company, which has since changed the program. Although it's unclear whether the benefits translate to the new brain game, the company still boasts about the results of the ACTIVE study on its website.
John Morris, MD, of Washington University in St. Louis, who wasn't involved in the report, said he does not endorse proprietary brain games for lowering dementia risk, and remains "dubious about their claims of benefit."
But generally, he said, the report's recommendations are "consistent with what I think almost all physicians who manage dementia patients also recommend: stay physically, mentally, and socially active; maintain a heart-healthy diet; and manage cardiovascular risk factors such as diabetes, hypertension, and dyslipidemia."
He emphasized the caveat that current data are "insufficient to indicate that any of these recommendations in fact lower risk for dementing illnesses such as Alzheimer disease. In a nutshell, they won't hurt anyone and they MAY help, but we don't know for sure that they are effective in lowering risk for dementia."