Malnutrition and neuropsychiatric symptoms in dementia: the Cache County Dementia Progression Study.

Objectives: Among people with dementia, poor nutritional status has been associated with worse cognitive and functional decline, but few studies have examined its association with neuropsychiatric symptoms (NPS). We examined this topic in a population-based sample of persons with dementia.

Design: Longitudinal, observational cohort study.

Setting: Community.

Participants: Two hundred ninety-two persons with dementia (71.9% Alzheimer's disease, 56.2% women) were followed up to 6 years.

Measurements: We used a modified Mini-Nutritional Assessment (mMNA) and the Neuropsychiatric Inventory (NPI) to evaluate nutritional status and NPS, respectively. Individual linear mixed effects models examined the associations between time-varying mMNA total score or clinical categories (malnourishment, risk for malnourishment, or well-nourished) and NPI total score (excluding appetite domain) or NPI individual domain or cluster (e.g. psychosis) scores. Covariates tested were dementia onset age, type, and duration, medical comorbidities, sex, apolipoprotein E (APOE) genotype, and education.

Results: Compared to the well-nourished, those at risk for malnourishment and those malnourished had higher total NPI scores [ (95% CI) = 1.76 (0.04, 3.48) or 3.20 (0.62, 5.78), respectively], controlling for significant covariates. Higher mMNA total score (better nutritional status) was associated with lower total NPI [ (95% CI) = -0.58 (-0.86, -0.29)] and lower domain scores for psychosis [ (95% CI) = -0.08 (-0.16, .004)], depression [ (95% CI = -0.11 (-0.16, -0.05], and apathy [ (95% CI = -0.19 (-0.28, -0.11)].

Conclusions: Worse nutritional status is associated with more severe NPS. Dietary or behavioral interventions to prevent malnutrition may be beneficial for persons with dementia.