Neuropsychiatric Symptoms as Risk Factors for Cognitive Decline in Clinically Normal Older Adults: The Cache County Study.

INTRODUCTION: There has been considerable progress in identifying early cognitive and biomarker predictors of Alzheimer's disease (AD). Neuropsychiatric symptoms (NPS) are common in AD and appear to predict progression after the onset of mild cognitive impairment or dementia. OBJECTIVES: The objective of the study is to examine the relationship between NPS in clinically normal older adults and subsequent cognitive decline in a population-based sample. METHODS: The Cache County Study on Memory in Aging consists of a population-based sample of 5,092 older adults. We identified 470 clinically normal adults who were followed for an average period of 5.73 years. NPS were evaluated at the baseline clinical assessment using the Neuropsychiatric Inventory (NPI). NPI domain scores were quantified as the product of frequency X severity in individual NPI domains, and then summed for the NPI-Total. Neuropsychological measures were collected at baseline and at each subsequent follow-up wave. Linear mixed-effects models assessed the association of NPI-Total, NPI-Depression, and NPI-Anxiety scores (obtained at baseline) on longitudinal change in neuropsychological performance, controlling for age, sex, and education. RESULTS: Baseline NPI-Total score was associated with a more rapid rate of decline in word list memory, praxis recall, and animal fluency. Baseline NPI-Depression was not associated with later decline on any of the cognitive tests, while baseline NPI-Anxiety was associated with decline in Symbol Digit Modality. CONCLUSION: In conclusion, among clinically normal older adults derived from this population-based study, total burden of NPS was associated with longitudinal cognitive decline. These results add to the evidence that NPS are risk factors for or clinical indicators of preclinical dementia syndrome. Our study was an exploratory study and we did not control for multiple comparisons.

Lifetime estrogen exposure and cognition in late life: the Cache County Study.

OBJECTIVE: Prevalence of Alzheimer's disease (AD) is higher for women, possibly influenced by sex-dependent effects of the estrogen. We examined the association between estrogen and cognitive decline in over 2,000 older adult women in a 12-year population-based study in Cache County, Utah. METHODS: The baseline sample included 2,114 women (mean age = 74.94 y, SD = 6.71) who were dementia-free at baseline and completed a women's health questionnaire, asking questions regarding reproductive history and hormone therapy (HT). Endogenous estrogen exposure (EEE) was calculated taking the reproductive window (age at menarche to age at menopause), adjusted for pregnancy and breastfeeding. HT variables included duration of use, HT type (unopposed; opposed), and time of HT initiation. A modified version of the Mini-Mental State Examination (3MS) was administered at four triennial waves to assess cognitive status. Linear mixed-effects models examined the relationship between estrogen exposure and 3MS score over time. RESULTS: EEE was positively associated with cognitive status (ß = 0.03, P = 0.054). In addition, longer duration of HT use was positively associated with cognitive status (ß = 0.02, P = 0.046) and interacted with age; older women had greater benefit compared with younger women. The timing of HT initiation was significantly associated with 3MS (ß = 0.55, P = 0.048), with higher scores for women who initiated HT within 5 years of menopause compared with those initiating HT 6-or-more years later. CONCLUSIONS: Our results suggest that longer EEE and HT use, especially in older women, are associated with higher cognitive status in late life.

Neuropsychiatric symptoms in severe dementia: Associations with specific cognitive domains the Cache County Dementia Progression Study.

OBJECTIVES: To examine the prevalence of neuropsychiatric symptoms (NPS) and cognitive correlates in severe dementia. METHODS: A population-based sample of 56 individuals with severe dementia (85.7% Alzheimer's type; 67.9% female) were assessed with the Severe Cognitive Impairment Profile (SCIP) and the Neuropsychiatric Inventory (NPI). Descriptive statistics displayed the frequency of NPS and bivariate and multiple regression analyses examined the associations between cognitive domains on the SCIP and NPS total, domain, and cluster scores. RESULTS: NPS were common in severe dementia with 98% of the sample exhibiting at least one symptom. Most common were delusions, apathy, agitation/aggression, and aberrant motor behavior, affecting 50% or more of participants. SCIP comportment was significantly associated with NPI total score and apathy (r = -.350 and -.292, respectively). All SCIP domains except for arithmetic, visuospatial, comportment, and motor behavior were significantly associated with agitation/aggression (r = -.285 to -.350). These associations remained in individual multiple regression models. CONCLUSION: In severe dementia, impairment in specific cognitive domains was associated with more severe NPS. Environmental manipulations to reduce processing demands in persons with severe dementia may be a useful strategy to target agitation and aggressive behaviors.

Caregiver-Care Recipient Relationship Closeness is Associated With Neuropsychiatric Symptoms in Dementia.

OBJECTIVE: Closer caregiver-care recipient (CG-CR) relationships are associated with better cognitive and functional abilities, activities of daily living (in persons with dementia), and lower informal care costs. METHODS: Due to the difficulty in treating neuropsychiatric symptoms (NPSs) and their detrimental effects on caregivers and care recipients, we examined whether closeness of CG-CR relationships was associated with overall NPS severity or with specific NPS symptom domains in care recipients. In a longitudinal population-based study in Cache County, Utah, the 12-item Neuropsychiatric Inventory (NPI-12) was assessed in 300 CG-CR dyads. Caregivers reported current relationship closeness using the Whitlatch Relationship Closeness Scale. Linear mixed models examined associations between CG-CR closeness and NPI-12 total score or selected symptom domains over time (observation period: 2002-2012). RESULTS: In unadjusted linear mixed models, higher closeness scores were associated with a five-point lower NPI-12 score and a one-point lesser increase in NPI-12 per year. NPI scores also showed lower affective cluster scores (two points) and lesser increase in psychosis cluster (approximately 0.5 points per year) and agitation/aggression (0.16 points per year) for each unit increase in closeness. When controlling for NPI caregiver distress, associations between closeness and NPSs diminished to a 0.5-point lesser increase in total NPI-12 score per year. Adjusted models for NPI domains/clusters showed -0.32 points per year for the psychosis cluster, -0.11 points per year for agitation/aggression, and -0.67 overall for the affective cluster. CONCLUSION: Higher CG-CR closeness, a potentially modifiable factor, is associated with lower NPS severity and may provide a target for intervention.

Use of FDA approved medications for Alzheimer's disease in mild dementia is associated with reduced informal costs of care.

ABSTRACTBackground:The use of FDA approved medications for Alzheimer's disease [AD; FDAAMAD; (cholinesterase inhibitors and N-methyl-D-aspartate receptor antagonists)] has been associated with symptomatic benefit with a reduction in formal (paid services) and total costs of care (formal and informal costs). We examined the use of these medications and their association with informal costs in persons with dementia. METHOD: Two hundred eighty participants (53% female, 72% AD) from the longitudinal, population-based Dementia Progression Study in Cache County, Utah (USA) were followed up to ten years. Mean (SD) age at baseline was 85.6 (5.5) years. Informal costs (expressed in 2015 dollars) were calculated using the replacement cost method (hours of care multiplied by the median wage in Utah in the visit year) and adjusted for inflation using the Medical Consumer Price Index. Generalized Estimating Equations with a gamma log-link function were used to examine the longitudinal association between use of FDAAMAD and informal costs. RESULTS: The daily informal cost for each participant at baseline ranged from $0 to $318.12, with the sample median of $9.40. Within the entire sample, use of FDAAMAD was not significantly associated with informal costs (expß = 0.73, p = 0.060). In analyses restricted to participants with mild dementia at baseline (N = 222), use of FDAAMAD was associated with 32% lower costs (expß = 0.68, p = 0.038). CONCLUSIONS: Use of FDAAMAD was associated with lower informal care costs in those with mild dementia only.

Sex Differences in Risk for Alzheimer's Disease Related to Neurotrophin Gene Polymorphisms: The Cache County Memory Study.

Neurotrophins, including nerve-growth factor and brain-derived neurotrophic factor, have been implicated in Alzheimer's disease (AD). Associations between AD and neurotrophin signaling genes have been inconsistent, with few studies examining sex differences in risk. We examined four single-nucleotide polymorphisms (SNPs) involved in neurotrophin signaling (rs6265, rs56164415, rs2289656, rs2072446) and risk for AD by sex in a population-based sample of older adults. Three thousand four hundred and ninety-nine individuals without dementia at baseline [mean (standard deviation) age = 74.64 (6.84), 58% female] underwent dementia screening and assessment over four triennial waves. Cox regression was used to examine time to AD or right censoring for each SNP. Female carriers of the minor T allele for rs2072446 and rs56164415 had a 60% (hazard ratio [HR] = 1.60, 95% confidence interval [CI] = 1.02-2.51) and 93% (HR = 1.93, 95% CI = 1.30-2.84) higher hazard for AD, respectively, than male noncarriers of the T allele. Furthermore, male carriers of the T allele of rs2072446 had a 61% lower hazard (HR = 0.39, 95% CI = 0.14-1.06) than male noncarriers at trend-level significance (p = .07). The association between certain neurotrophin gene polymorphisms and AD differs by sex and may explain inconsistent findings in the literature.