Which Interventions Can Slow Cognitive Decline or Prevent Dementia?
Physical Activity
Although the randomized controlled trial data on the benefits of physical activity were mixed, the results suggested that physical activity could reduce the risk of age-related cognitive decline. Data on the effect of physical activity on the risks of MCI and Alzheimer’s-type dementia were insufficient, Dr. Petersen said. Generally, follow-up periods were too short to assess long-term effects, and MCI and Alzheimer’s-type dementia incidence were rarely measured as outcomes.
“Findings from studies that compared the difference between aerobic training and resistance training were somewhat inconsistent,” Dr. Petersen said. “Some people believe that a mixture of both may in fact be beneficial.” In the largest randomized controlled trial examined, the Lifestyle Interventions and Independence for Elders Pilot study, evidence was insufficient to support conclusions regarding a multicomponent intervention.
“There were observational studies and a variety of longitudinal prospective studies that would suggest that physical activity may have a positive effect on cognitive performance and dementia incidence,” Dr. Petersen said. “It could also have an impact on other conditions that may affect cognitive function, such as hypertension, depression, and diabetes.”
Future Directions for Research
While the NASEM committee recommends more research on the benefits of cognitive training, blood pressure management, and exercise training, it also urges the NIH and other organizations to support studies with improved methodologies. Such improvements include identifying patients at higher risk of cognitive decline or dementia, increasing participation of underrepresented populations, beginning interventions at younger ages, and establishing longer follow-up periods.
The committee also suggests that trials with other primary purposes measure cognitive outcomes. “For instance, if there is an ongoing study on prostate cancer, and the researchers decide midway to add some cognitive measure, that is useful,” Dr. Petersen said. “But it is not as strong as if the study had been prospectively designed to look at cognitive end points at the baseline.”
Other interventions that should be examined are new antidementia treatments; treatments for diabetes and depression; dietary, lipid-lowering, and sleep-quality interventions; social engagement interventions; and supplementation with vitamin B12 plus folic acid, said Dr. Petersen.
—Adriene Marshall
Suggested Reading
Forette F, Seux ML, Staessen JA, et al. Prevention of dementia in randomised double-blind placebo-controlled Systolic Hypertension in Europe (Syst-Eur) trial. Lancet. 1998;352(9137):1347-1351.
Jobe JB, Smith DM, Ball K, et al. ACTIVE: a cognitive intervention trial to promote independence in older adults. Control Clin Trials. 2001;22(4):453-479.
LIFE Study Investigators, Pahor M, Blair SN, et al. Effects of a physical activity intervention on measures of physical performance: Results of the Lifestyle Interventions and Independence for Elders Pilot (LIFE-P) study. J Gerontol A Biol Sci Med Sci. 2006;61(11):1157-1165.
National Academies of Sciences, Engineering, and Medicine. 2017. Preventing Cognitive Decline and Dementia: A Way Forward. Washington, DC: The National Academies Press; 2017.
Staessen JA, Thijs L, Birkenhäger WH, et al. Update on the systolic hypertension in Europe (Syst-Eur) trial. The Syst-Eur Investigators. Hypertension. 1999;33(6):1476-1477.
