Relationship of Nutritional Factors to Cognitive Decline in the Progression of Dementia: The Cache County Dementia Progression Study

Previous studies have found nutritional status to predict better functional and cognitive ability in dementia. The current study investigated the relationship between nutritional status and progression of neuropsychological impairment in a U.S. sample of persons with dementia. Participants were studied for up to 6 years in the population-based Cache County, UT, study. Baseline sample included 240 persons with dementia (71.3% Alzheimer’s disease, 52.1% female). Mean (SD) age and dementia duration at baseline was 85.6 (5.2) and 3.4 (1.9) years, respectively. Consortium to Establish a Registry for Alzheimer’s Disease (CERAD) neuropsychological test battery and Boston Naming Test (30-item) were administered annually. Nutritional status was assessed using a modified Mini Nutritional Assessment (mMNA). Components of nutritional status were chosen for further investigation (dietary intake and BMI). Linear mixed effects models examined change in nutritional status and food consumption over time as well as the association between mMNA and its components (time-varying) with each neuropsychological measure and rate of decline over time. The following covariates were tested as appropriate: dementia type, gender, age of dementia onset and duration (at baseline), education, neuropsychiatric symptoms, caregiver coresidence, place of residence, overall health, and dementia severity. mMNA scores decreased by .22 pts/year (p = .006), though this was confounded by dementia severity (β = -.12, p = .108). Consumption of carbohydrates (β = -.09), protein (β = -.07) and fruit/vegetables (β = -.08) also declined over time, all p \u3c .05). Better nutritional status was associated with better neuropsychological test scores across all visits in verbal learning (β = .23), praxis drawing (β = .23), praxis memory (β = .08), verbal fluency (β = .34) and confrontation naming (β = .31), while mMNA predicted rate of decline in verbal recognition memory (β = .13); all p \u3c .001, with the inclusion of covariates. Higher protein intake was associated with worse verbal learning, while higher BMI predicted better scores on all neuropsychological tests except for confrontation naming. The results emphasize the importance of nutritional status in dementia and raises the possibility of nutritional interventions that may improve patient outcomes