Longer Term Effects of Diet and Exercise on Neurocognition: 1-Year Follow-up of the ENLIGHTEN Trial

Abstract

Objectives: To evaluate the longer term changes in executive functioning among participants with cardiovascular disease (CVD) risk factors and cognitive impairments with no dementia (CIND) randomized to a diet and exercise intervention.

Design: A 2 (Exercise) × 2 (Dietary Approaches to Stop Hypertension [DASH] eating plan) factorial randomized clinical trial.

Setting: Academic tertiary care medical center.

Participants: Volunteer sample of 160 older sedentary adults with CIND and at least one additional CVD risk factor enrolled in the ENLIGHTEN trial between December 2011 and March 2016.

Interventions: Six months of aerobic exercise (AE), DASH diet counseling, combined AE + DASH, or health education (HE) controls.

Measurements: Neurocognitive battery recommended by the Neuropsychological Working Group for Vascular Cognitive Disorders including measures of executive function, memory, and language/verbal fluency. Secondary outcomes included the Clinical Dementia Rating-Sum of Boxes (CDR-SB), Six-Minute Walk Distance (6MWD), and CVD risk including blood pressure, body weight, and CVD medication burden.

Results: Despite discontinuation of lifestyle changes, participants in the exercise groups retained better executive function 1 year post-intervention (P = .041) compared with non-exercise groups, with a similar, albeit weaker, pattern in the DASH groups (P = .054), without variation over time (P's > .867). Participants in the exercise groups also achieved greater sustained improvements in 6MWD compared with non-Exercise participants (P < .001). Participants in the DASH groups exhibited lower CVD risk relative to non-DASH participants (P = .032); no differences in CVD risk were observed for participants in the Exercise groups compared with non-Exercise groups (P = .711). In post hoc analyses, the AE + DASH group had better performance on executive functioning (P < .001) and CDR-SB (P = .011) compared with HE controls.

Conclusion: For participants with CIND and CVD risk factors, exercise for 6 months promoted better executive functioning compared with non-exercisers through 1-year post-intervention, although its clinical significance is uncertain. J Am Geriatr Soc 68:559-568, 2020.

Trial registration: ClinicalTrials.gov NCT01573546.

Keywords: Dietary Approaches to Stop Hypertension diet; cardiovascular risk; cognitive impairment no dementia; executive functioning; exercise.