“I hope this study will motivate people to engage in a healthy lifestyle by not smoking, being physically and cognitively active, and having a high-quality diet,” lead investigator Klodian Dhana, MD, PhD, department of internal medicine, Rush University Medical Center, Chicago, said in an interview.
The study was published online June 17 in Neurology.
Risk-modifying behaviors
To help quantify the impact of a healthy life on risk for Alzheimer’s dementia, Dr. Dhana and colleagues reviewed data from two longitudinal study populations: the Chicago Health and Aging Project (CHAP), with 1,845 participants, and the Memory and Aging Project (MAP), with 920 participants.
They defined a healthy lifestyle score on the basis of the following factors: not smoking; engaging in 150 min/wk or more of physical exercise of moderate to vigorous intensity; light to moderate alcohol consumption (between 1 and less than 15 g/day for women and between 1 and less than 30 g/day for men); consuming a high-quality Mediterranean-DASH Diet Intervention for Neurodegenerative Delay diet (upper 40%); and engaging in late-life cognitive activities (upper 40%). The overall score ranged from 0 to 5.
At baseline, the mean age of participants was 73.2 years in the CHAP study and 81.1 years in the MAP study; 62.4% of the CHAP participants and 75.2% of the MAP participants were women.
During a median follow-up of 5.8 years in CHAP and 6.0 years in MAP, a total of 379 and 229 participants, respectively, developed Alzheimer’s dementia. Rates of dementia decreased with an increasing number of healthy lifestyle behaviors.
In multivariable-adjusted models across the two cohorts, the risk for Alzheimer’s dementia was 27% lower with each additional healthy lifestyle factor (pooled hazard ratio, 0.73; 95% confidence interval, 0.66-0.80).
Compared with individuals with a healthy lifestyle score of 0-1, the risk was 37% lower (pooled HR, 0.63; 95% CI, 0.47-0.84) for those with two or three healthy lifestyle factors and 60% lower (pooled HR, 0.40; 95% CI, 0.28-0.56) for those with four or five healthy lifestyle factors.
“From these findings and the fact that the lifestyle factors we studied are modifiable and in direct control of the individual, it is imperative to promote them concurrently among older adults as a strategy to delay or prevent Alzheimer’s dementia,” Dr. Dhana and colleagues concluded.
In a statement, Dallas Anderson, PhD, program director, division of neuroscience, National Institute on Aging, said the findings help “paint the picture of how multiple factors are likely playing parts in Alzheimer’s disease risk.”
“It’s not a clear cause-and-effect result, but a strong finding because of the dual data sets and combination of modifiable lifestyle factors that appear to lead to risk reduction,” Dr. Anderson added.
Essential questions remain
Commenting on the new study, Luca Giliberto, MD, PhD, neurologist with the Litwin-Zucker Research Center for Alzheimer’s Disease and Memory Disorders at the Feinstein Institutes for Medical Research in Manhasset, N.Y., said this analysis is “further demonstration that a healthy lifestyle is essential to overcome or curb” the risk for Alzheimer’s disease.
“What needs to be determined is how early should we start ‘behaving.’ We should all aim to score four to five factors across our entire lifespan, but this is not always feasible. So, when is the time to behave? Also, what is the relative weight of each of these factors?” said Dr. Giliberto.
Of note, he added, although addressing vascular risk factors such as hypertension, hyperlipidemia, and diabetes “may require an extensive mindful and logistic effort, a healthy diet is effortlessly achieved in some countries, where both the DASH and MIND diets do not need to be ‘prescribed’ but are rather culturally engraved in the population.
“This is, in part, related to the wide availability of high-quality food in these countries, which is not the same in the U.S. This work is one more demonstration of the need to revisit our take on quality of food in the U.S.,” said Dr. Giliberto.
Numerous clinical trials testing lifestyle interventions for dementia prevention are currently underway. The MIND Diet Intervention to Prevent Alzheimer’s Disease, for example, is an interventional clinical trial comparing parallel groups with two different diets. MIND has enrolled more than 600 participants and is ongoing. The anticipated completion date is 2021. Another is the U.S. Study to Protect Brain Health Through Lifestyle Intervention to Reduce Risk (U.S. POINTER), a multisite randomized clinical trial evaluating whether lifestyle interventions – including exercise, cognitively stimulating activities, and the MIND diet – may protect cognitive function in older adults who are at increased risk for cognitive decline.
Funding for the current study was provided by the National Institutes of Health and the National Institute on Aging. Dr. Dhana and Dr. Giliberto have disclosed no relevant financial relationships.
A version of this article originally appeared on Medscape.com.