The randomized clinical trial, which was called the Exercise and Nutritional Interventions for Cognitive and Cardiovascular Health Enhancement (ENLIGHTEN) study, found aerobic exercise and a healthy diet improved patients’ ability to function and to think, remember, and make decisions.
In an effort to assess whether lifestyle modifications that are effective in reducing the development of cardiovascular disease could slow cognitive decline in older adults with cognitive impairment without dementia, investigators conducted the ENLIGHTEN study in 160 adults at the Duke University Medical Center. Patients included were randomized to 1 of 4 interventions groups—interventions included aerobic exercise alone, Dietary Approach to Stop Hypertension (DASH) diet alone, a combination of the DASH diet and aerobic exercise, and a health education control group.
Of the 160 patients included, 40 were randomized to the combination group, 41 to exercise alone, 41 to diet alone, and 38 to the health education group. For inclusion in the study, patients needed to be 55 or older, have subjective memory or cognitive complaints, be sedentary, and have documented cardiovascular disease at least 1 additional cardiovascular disease risk factor.
For the purpose of the study, aerobic exercise was defined as 35 minutes of moderate-intensity aerobic exercise 3 times per week for 6 months. Patients randomized to a group that included the DASH diet received instruction on modifying their diet in weekly sessions for 3 months and then biweekly sessions for an additional 3 months.
Patients in the health education control group received weekly education phone calls for 3 months and then biweekly calls for an additional 3 months. Patients in the combination group underwent both DASH and aerobic exercise interventions.
Primary outcome measure for the study was global executive function while secondary endpoints included assessments of memory and language/verbal fluency. Investigators pointed out patients were free to engage in whatever activity or dietary habits they chose after 6 months and all patients included in the analyses participated in a follow-up at 12 months.
Upon analysis, investigators found patients in the exercise groups were able to maintain higher levels of executive function at 1-year compared to patients in non-exercise groups (d=0.27; P=0.041). This association was weaker but still present when compared to DASH groups (d=0.20; P=0.054). Additionally, patients in the exercise groups achieved greater sustained improvements in the 6-Minute Walk Test compared to those in non-exercise groups.
When examining rates of cardiovascular disease, results revealed patients randomized to DASH groups had lower risk compared to patients not included in DASH groups (P=0.32). Furthermore, no differences between participants in exercise groups and non-exercise groups when assessing cardiovascular disease risk (P=0.711).
Post-hoc analyses revealed participants in the combination group had better performance in regard to executive function (P<0.001) and Clinical Dementia Rating-Sum of Boxes (P=0.011) compared to patients in the health education control group.
This study, titled “Longer Term Effects of Diet and Exercise on Neurocognition: 1‐Year Follow‐up of the ENLIGHTEN Trial,” was published online in Journal of the American Geriatrics Society.