Lifestyle and neurocognition in older adults with cognitive impairments: A randomized trial

Abstract

Objective: To determine the independent and additive effects of aerobic exercise (AE) and the Dietary Approaches to Stop Hypertension (DASH) diet on executive functioning in adults with cognitive impairments with no dementia (CIND) and risk factors for cardiovascular disease (CVD).

Methods: A 2-by-2 factorial (exercise/no exercise and DASH diet/no DASH diet) randomized clinical trial was conducted in 160 sedentary men and women (age >55 years) with CIND and CVD risk factors. Participants were randomly assigned to 6 months of AE, DASH diet nutritional counseling, a combination of both AE and DASH, or health education (HE). The primary endpoint was a prespecified composite measure of executive function; secondary outcomes included measures of language/verbal fluency, memory, and ratings on the modified Clinical Dementia Rating Scale.

Results: Participants who engaged in AE (d = 0.32, p = 0.046) but not those who consumed the DASH diet (d = 0.30, p = 0.059) demonstrated significant improvements in the executive function domain. The largest improvements were observed for participants randomized to the combined AE and DASH diet group (d = 0.40, p = 0.012) compared to those receiving HE. Greater aerobic fitness (b = 2.3, p = 0.049), reduced CVD risk (b = 2.6, p = 0.042), and reduced sodium intake (b = 0.18, p = 0.024) were associated with improvements in executive function. There were no significant improvements in the memory or language/verbal fluency domains.

Conclusions: These preliminary findings show that AE promotes improved executive functioning in adults at risk for cognitive decline.

Clinicaltrialsgov identifier: NCT01573546.

Classification of evidence: This study provides Class I evidence that for adults with CIND, AE but not the DASH diet significantly improves executive functioning.

Figure 1. Consolidated Standards of Reporting Trials flowchart

Twenty-four patients were excluded for logistic reasons (e.g., they had no transportation, lived too far from Duke University Medical Center, or had plans for extended absences during the 6 months of active intervention). These patients were excluded before completing baseline assessments and before randomization. AE = aerobic exercise; BMI = body mass index; CVRF = cardiovascular risk factor; DASH = Dietary Approaches to Stop Hypertension; ITT = intention to treat; MoCA = Montreal Cognitive Assessment.

Figure 2. Intervention effects for (A) global executive function and (B) mCDR

Values for the global composite are presented as mean postintervention ranks adjusted for preintervention rank, age, education, sex, ethnicity, baseline Montreal Cognitive Assessment (MoCA) score, APOE genotype, Framingham Stroke Risk Profile (FSRP), and anti-inflammatory and cardiovascular disease (CVD) medications. Higher scores represent better performance. For the modified Clinical Dementia Rating (mCDR), values are presented as mean postintervention mCDR Sum of Boxes scores adjusted for preintervention scores, age, education, sex, ethnicity, pretreatment MoCA score, APOE genotype, FSRP, anti-inflammatory, and CVD medications. Lower scores represent greater improvement. AE = aerobic exercise; DASH = Dietary Approaches to Stop Hypertension; HE = health education.