Hazard Ratio For Incident Dementia Research Articles

Does social isolation mediate the association between hearing loss and cognition in adults? A systematic review and meta-analysis of longitudinal studies.

There has been extensive research on the relationship between hearing and cognitive impairment in older adults but little examination of the role of mediating factors. Social isolation is a potential mediator, occurring because of hearing loss, and contributing to accelerated cognitive decline. Previous systematic reviews on this topic area have not considered the temporal nature of hearing loss and cognitive impairment exclusively or examined potential mediators within a longitudinal study design. A systematic review was conducted. Electronic searches were performed in Web of Science, PubMed (Medline), Scopus, EMBASE, PsychInfo, and ProQuest (PsychArticles and ProQuest Dissertation and Theses) based on a search string of keywords relating to hearing loss, social isolation, and cognitive impairment/dementia in June 2023. Papers were critically appraised using the CASP checklists for cohort studies. Risk of bias in the selected studies was assessed using the Item Bank for Assessment of Risk of Bias and Precision for Observational Studies of Interventions or Exposures. Eleven of the 15 included studies provide evidence of a dose-dependent association between hearing threshold (40 dB HL or greater) and later cognitive impairment or incident dementia. Only one study included social isolation as a mediator, which was found to not be a significant contributing factor. The meta-analysis of 5 studies pooled hazard ratio for cognitive impairment due to hearing loss is 1.11 (95% CI: 1.06 to 1.15, p < 0.001). The pooled hazard ratio for incident dementia due to hearing loss was HR 1.21 (95% CI: 1.11 to 1.31, p = 0.002). The analysis of included studies indicate that hearing threshold level affects later cognitive status or dementia diagnosis. There is not enough evidence to determine the role of social isolation as a mediator. Future epidemiology studies need to measure different elements of social isolation and ensure that hearing and cognition are measured at multiple time points.

Motoric Cognitive Risk and Incident Dementia in Older Adults

Motoric cognitive risk (MCR) is a novel predementia syndrome; however, whether it can estimate dementia in a nationwide population or has additive estimation validity over cognitive or motoric components alone remains unknown. To examine whether modified MCR, which incorporates the timed-up-and-go and one-leg-standing tests, improves estimation validity for incident dementia over using cognitive or motoric components alone. This nationwide cohort study evaluated data from individuals aged 66 years who participated in the National Screening Program for Transitional Ages in Korea from January 1, 2009, to December 31, 2013, and examined the association between MCR and incident dementia using Cox proportional hazards regression analysis. Data were collected from the index date (the date on which the participant had the screening) until dementia onset, death, or the end of the follow-up period, whichever came first. The 2 subtypes were defined as subjective cognitive declines with timed-up-and-go impairment or one-leg-standing impairment. The data set was generated with permission from the Korean National Health Insurance Service, and data analysis was conducted from August 2, 2021, to January 31, 2022. Individuals diagnosed with dementia or psychotic disorders or those who had a documented history of dementia medication use before the index date were excluded. The main outcome was incidence of dementia, defined as an individual receiving their first dementia medication with the relevant International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, codes after the index date. Among the 1 137 530 participants (53.7% women), 15 380 (1.4%) met the MCR criteria for the timed-up-and-go subtype, and 32 910 (2.9%) met the criteria for the one-leg-standing subtype. The mean (SD) follow-up period was 7.02 (1.38) years. Participants with MCR demonstrated an approximately 2-fold higher risk of incident dementia than those without MCR (timed-up-and-go subtype, adjusted hazard ratio, 2.03; 95% CI, 1.94-2.13; one-leg-standing subtype, adjusted hazard ratio, 2.05; 95% CI, 1.98-2.12). In this cohort study of participants aged 66 years of the National Screening Program for Transitional Ages, modified motoric cognitive risk had higher adjusted hazard ratios of incident dementia than individual cognitive or motoric components. Motoric cognitive risk may be a practical screening tool for estimating dementia among individuals in their mid-60s ; however, further investigation of the clinical and neurobiological aspects is necessary.

Migraine, Cognitive Decline, and Dementia in Older Adults: A Population-Based Study.

The potential impact of migraine on cognitive aging among older adults remains controversial. To examine the relationship of migraine and subtypes with cognitive decline and dementia in an older Swedish population. This population-based study included 3,069 participants (age ≥ 60 years) from the Swedish National study on Aging and Care in Kungsholmen, Stockholm. Baseline examination was conducted in 2001-2004, and participants were followed every 3 or 6 years until 2013-2016. Data were collected through face-to-face interviews, clinical examinations, laboratory tests, and linkage with registers. Global cognitive function was measured with the Mini-Mental State Examination (MMSE). Dementia was diagnosed according to the DSM-IV criteria. Migraine and subtypes were defined following the international classification system. Data were analyzed using logistic regression, Cox regression, and linear mixed-effects models. At baseline, 305 participants were defined with non-migraine headache and 352 with migraine. The cross-sectional analysis showed that the multivariable-adjusted odds ratio (95% confidence interval) of prevalent dementia was 0.49 (0.20-1.21) for migraine and 0.66 (0.26-1.66) for migraine without aura. The longitudinal analysis showed that the multivariable-adjusted hazard ratios of incident dementia associated with migraine and subtypes ranged 0.68-0.89 (p > 0.05). Furthermore, migraine and subtypes were not significantly associated with either baseline MMSE score or MMSE changes during follow-ups (p > 0.05). The nonsignificant associations did not vary substantially by age, APOEɛ4 allele, cerebrovascular disease, and antimigraine treatment (p for interactions > 0.05). This study shows no evidence supporting the associations of migraine and its subtypes with cognitive decline and dementia among older adults.

Practice Effects in Mild Cognitive Impairment Increase Reversion Rates and Delay Detection of New Impairments.

ObjectiveCognitive practice effects (PEs) can delay detection of progression from cognitively unimpaired to mild cognitive impairment (MCI). They also reduce diagnostic accuracy as suggested by biomarker positivity data. Even among those who decline, PEs can mask steeper declines by inflating cognitive scores. Within MCI samples, PEs may increase reversion rates and thus impede detection of further impairment. Within an MCI sample at baseline, we evaluated how PEs impact prevalence, reversion rates, and dementia progression after 1 year.MethodsWe examined 329 baseline Alzheimer’s Disease Neuroimaging Initiative MCI participants (mean age = 73.1; SD = 7.4). We identified test-naïve participants who were demographically matched to returnees at their 1-year follow-up. Since the only major difference between groups was that one completed testing once and the other twice, comparison of scores in each group yielded PEs. PEs were subtracted from each test to yield PE-adjusted scores. Biomarkers included cerebrospinal fluid phosphorylated tau and amyloid beta. Cox proportional models predicted time until first dementia diagnosis using PE-unadjusted and PE-adjusted diagnoses.ResultsAccounting for PEs increased MCI prevalence at follow-up by 9.2% (272 vs. 249 MCI), and reduced reversion to normal by 28.8% (57 vs. 80 reverters). PEs also increased stability of single-domain MCI by 12.0% (164 vs. 147). Compared to PE-unadjusted diagnoses, use of PE-adjusted follow-up diagnoses led to a twofold increase in hazard ratios for incident dementia. We classified individuals as false reverters if they reverted to cognitively unimpaired status based on PE-unadjusted scores, but remained classified as MCI cases after accounting for PEs. When amyloid and tau positivity were examined together, 72.2% of these false reverters were positive for at least one biomarker.InterpretationEven when PEs are small, they can meaningfully change whether some individuals with MCI retain the diagnosis at a 1-year follow-up. Accounting for PEs resulted in increased MCI prevalence and altered stability/reversion rates. This improved diagnostic accuracy also increased the dementia-predicting ability of MCI diagnoses.

Association Between Inflammatory Bowel Disease and Dementia: A Longitudinal Cohort Study.

BackgroundThe association between inflammatory bowel disease (IBD) and dementia remains uncertain. We aim to investigate whether IBD is associated with higher dementia risk.MethodsUsing multivariable Cox regression models, we analyzed the onset of all-cause dementia among 497,775 participants, including 5778 IBD patients in the UK Biobank as primary analysis. In secondary analysis, we further examined the difference in brain structure and cognitive function changes between IBD and non-IBD individuals. The diagnosis of IBD and dementia was confirmed with combination of primary care data, hospital inpatient data, death registry, and self-report data. Brain structure was measured by brain MRI as anatomic and tissue-specific volumes; cognitive function was tested in terms of reaction, visual episodic memory, verbal-numerical reasoning, and prospective memory.ResultsDuring a mean follow-up of 11.58 years, 100 and 6709 incident all-cause dementia with or without IBD were documented, respectively. In multivariable Cox regression model, hazard ratio for incident dementia among IBD patients was 1.14 (95% confidence interval [CI], 0.94-1.39; P=.182) comparing with non-IBD participants; no statistically significant difference was observed in their brain MRI measures of anatomic and tissue-specific volumes, whereas IBD patients had a significantly increased reaction time (β=12.32; 95% CI, 1.97, 22.67; P = .020). Results of subgroup and sensitivity analyses were consistent with the main analysis.ConclusionsOur study does not support a significant association between IBD and dementia. Further studies with better design and longer follow-up are needed to elucidate the association.

The Relationship Between Fertility History and Incident Dementia in the U.S. Health and Retirement Study.

An emerging literature suggests that fertility history, which includes measures of parity and birth timing, may influence cognitive health in older ages, especially among women given their differential exposure to pregnancy and sex hormones. Yet, few studies have examined associations between measures of fertility history and incident dementia in population-based samples. We examined the associations between parity, younger age at first birth, and older age at last birth with incident dementia over a 16-year period in a prospective sample of 15,361 men and women aged 51-100 years at baseline drawn from the Health and Retirement Study. We used Cox regression and the Fine and Gray model to obtain cause-specific hazard ratios (csHRs) and subdistribution hazard ratios for incident dementia from gender-stratified models, with the latter method accounting for the semicompeting risk of death. During the follow-up period (median 13.0 years), the crude incidence rate for dementia was 16.6 and 19.9 per 1,000 person-years for men and women, respectively. In crude models estimating csHRs, higher parity (vs parity 2) and younger age at first birth were associated with increased risk of dementia for both genders. These associations did not persist after adjusting for sociodemographic characteristics, smoking status, and health conditions, with much of the attenuation in estimates occurring after adjustment for sociodemographic characteristics. In this population-based, multiethnic cohort, we observed limited evidence for an association between measures of fertility history and incident dementia among men and women after adjusting for potential confounders.

Local Contrasts in Concentration of Ambient Particulate Air Pollution (PM2.5) and Incidence of Alzheimer's Disease and Dementia: Results from the Betula Cohort in Northern Sweden.

Exposure to fine particulate air pollution (PM2.5) is emerging as a risk factor for Alzheimer’s disease (AD), but existing studies are still limited and heterogeneous. We have previously studied the association between dementia (AD and vascular dementia) and PM2.5 stemming from vehicle exhaust and wood-smoke in the Betula cohort in Northern Sweden. The aim of this commentary is to estimate the association between total PM2.5 and dementia in the Betula cohort, which is more relevant to include in future meta-estimates than the source-specific estimates. The hazard ratio for incident dementia associated with a 1μg/m3 increase in local PM2.5 was 1.38 (95% confidence interval: 0.99 –1.92). The interpretation of our results is that they indicate an association between local contrasts in concentration of PM2.5 at the residential address and incidence of dementia in a low-level setting.

Comparison of dementia risk after age 50 between individuals with and without HIV infection.

To compare risk of dementia after age 50 by HIV status among individuals in a primary care setting. Observational cohort study; participants were identified from 2013 to 2017 and followed through 2019. Participants were people with HIV (PWH) on antiretroviral therapy (ART) and demographically similar people without HIV (PWOH), all at least 50 years old and with no prior diagnosis of dementia. The study setting was Kaiser Permanente Northern California, an integrated healthcare delivery system in the United States. Incident dementia diagnoses and baseline data on sociodemographics, smoking, alcohol use, other substance use, and clinical factors were gathered from the electronic health record. Cumulative proportion of incident dementia by HIV status was assessed using Kaplan--Meier curves. Unadjusted and adjusted hazard ratios for incident dementia by HIV status were generated using Cox proportional hazards models with age as the time scale. The study included 5381 PWH and 119 022 PWOH (average age at baseline: 57 and 58 years, respectively). Incident dementia was diagnosed in 117 PWH and 2427 PWOH. By age 80, 25.8% of PWH and 13.8% of PWOH had been diagnosed with dementia, corresponding with an unadjusted hazard ratio of 1.98 (95% CI 1.64-2.39). After adjustment for sociodemographic, substance use, and clinical factors, including frequency of outpatient visits, the risk of dementia among PWH remained elevated (vs. PWOH, adjusted hazard ratio = 1.58, 95% CI 1.31-1.92). Compared with PWOH, PWH were at 58% higher risk for dementia despite HIV treatment with ART. Research is needed to investigate the potential benefits of targeted risk factor management or earlier cognitive screening in this population.

Interaction of neuropsychiatric symptoms with APOE e4 and conversion to dementia in MCI patients in a memory clinic

AbstractBackgroundTo the date, scarce studies have been focused in the impact of the convergence of neuropsychiatric symptoms (NPS) and APOE e4 on conversion to dementia in Mild Cognitive Impaired patients (MCI). None of them taking into account clinical settings of MCI patients. The objective was to determine the predictive value of additive and multiplicative interactions of NPS and APOE e4 status on the prediction of incident dementia among MCI patients monitored in a Memory Clinic.Method1512 patients (aged 60 and older) with prevalent MCI have been followed for a mean of 2 years. Neuropsychiatric symptoms were assessed at baseline using the Neuropsychiatric Inventory Questionnaire. Cox proportional hazards models were calculated, and several clinical variables were used as an adjusting factors, including the memory impairment condition, the attributed etiological pattern, and the antidepressant and anxiolytic medication used.ResultAdditive interactions for depression, apathy, anxiety, agitation, appetite, or irritability and a positive ε4 carrier status were obtained, increasing significantly the hazard ratios of incident dementia (HR range 1.3 – 2.03).ConclusionSynergistic interactions between NPS and APOE e4 are identified among MCI patients when predicting incident dementia. The combination of the behavioral status and the genetic trait could be considered a useful strategy to identify the most vulnerable MCI patients to dementia conversion in a Memory Clinic.

Interaction of neuropsychiatric symptoms with APOE \u03b54 and conversion to dementia in MCI patients in a Memory Clinic

To date, very few studies have been focused on the impact of the convergence of neuropsychiatric symptoms (NPS) and APOE ε4 on the conversion to dementia in patients with Mild Cognitive Impairment patients (MCI), and none has been based in a clinical setting. The objective of the study is to determine the predictive value of additive and multiplicative interactions of NPS and APOE ε4 status on the prediction of incident dementia among MCI patients monitored in a Memory Clinic. 1512 patients (aged 60 and older) with prevalent MCI were followed for a mean of 2 years. Neuropsychiatric symptoms were assessed at baseline using the Neuropsychiatric Inventory Questionnaire. Cox proportional hazards models were calculated. Additive interactions for depression, apathy, anxiety, agitation, appetite, or irritability and a positive ε4 carrier status were obtained, significantly increasing the hazard ratios of incident dementia (HR range 1.3–2.03). Synergistic interactions between NPS and APOE ε4 are identified among MCI patients when predicting incident dementia. The combination of the behavioral status and the genetic trait could be considered a useful strategy to identify the most vulnerable MCI patients to dementia conversion in a Memory Clinic.

Periodontal disease and incident dementia: The Atherosclerosis Risk in Communities Study (ARIC).

To test the hypothesis that periodontal disease would be associated with increased risk for dementia and mild cognitive impairment (MCI) by assessing dementia/MCI outcomes after a baseline periodontal examination. Participants enrolled in the Atherosclerosis Risk in Communities study with a clinical periodontal examination (or edentulous participants) at visit 4 (1996-1998; mean ± SD age 63 ± 6 years, 55% female, 21% black) and adjudicated dementia outcomes through 2016 were included (n = 8,275). A subgroup of 4,559 participants had adjudicated dementia and MCI assessments at visit 5 (2011-2013). Participants received a full-mouth periodontal examination and were classified into periodontal profile classes (PPCs) based on the severity and extent of gingival inflammation and attachment loss. MCI and dementia were determined via neurocognitive testing, neurological examination and history, informant interviews, and brain MRI in a subset. Cox proportional hazards models regressed incident dementia on PPCs. Relative risk regression models were used for the composite of MCI/dementia. The cumulative incidence and incidence density of dementia during follow-up (average 18.4 years) were 19% (n = 1,569) and 11.8 cases per 1,000 person-years. Multivariable adjusted hazard ratios for incident dementia among participants with severe PPC or edentulism (vs periodontal healthy) were 1.22 (95% confidence interval [CI] 1.01-1.47) and 1.21 (95% CI 0.99-1.48), respectively. For the combined dementia/MCI outcome, adjusted risk ratios among participants with mild/intermediate PPC, severe PPC, or edentulism (vs periodontal healthy) were 1.22 (95% CI 1.00-1.48), 1.15 (95% CI 0.88-1.51), and 1.90 (95% CI 1.40-2.58). Results were stronger among younger (≤62 years) participants (p for interaction = 0.02). Periodontal disease was modestly associated with incident MCI and dementia in a community-based cohort of black and white participants.

Joint impact of common risk factors on incident dementia: A cohort study of the Swedish Twin Registry.

As common risk factors of dementia, nine factors (low education, hearing loss, obesity, hypertension, smoking, depression, physical inactivity, diabetes and social isolation) were proposed. However, the joint impact of these factors on incident dementia is still uncertain; hence, we aimed to examine this impact. We conducted a cohort study of 9017 cognitively intact individuals aged≥65years in the Swedish Twin Registry. The main exposure was the total number of reported risk factors (ranging from 0 to 9). Data on dementia diagnoses were based on clinical workup and national health registers. After estimating the adjusted hazard ratios of incident dementia, the population attributable fraction (PAF) was calculated. We then conducted additional analyses, including APOE ε4 status in a genotyped subsample (n=2810) to check the relative impact of the main exposure and discordant twin pair (n=1158) analysis to consider confounding by familial effects (shared genetic or familial environmental factors). The number of dementia cases was 1950 (21.6%). A dose-response relationship between the number of risk factors and incident dementia was observed; hazard ratio (95% confidence interval) per one-unit increment in number of risk factors was 1.07 (1.03 to 1.11). The PAF for the combination of the nine risk factors was 10.4%. The PAF of all nine risk factors was smaller than that of APOE ε4 genotype (20.8%) in the subsample. Discordant pair analysis suggested that the observed association was notlikely explained by familial effects. The nine risk factors may have considerable impact as modifiable factors on incident dementia.

Vitamin D status, cognitive decline and incident dementia: the Canadian Study of Health and Aging.

Vitamin D could prevent cognitive decline because of its neuroprotective, anti-inflammatory and antioxidant properties. This study aimed to evaluate the associations of plasma 25-hydroxyvitamin D (25(OH)D) concentrations with global cognitive function and incident dementia, including Alzheimer's disease (AD). The Canadian Study of Health and Aging is a 10-year cohort study of a representative sample of individuals aged 65 yearsor older. A total of 661 subjects initially without dementia with frozen blood samples and follow-up data were included. Global cognitive function was measured using the validated Modified Mini-Mental State (3MS) examination. A consensus diagnosis of all-cause dementia and AD was made between the physician and the neuropsychologist according to published criteria. Cognitive declinefor a 5-year increase in age at specific 25(OH)D concentrations was obtained using linear mixed models with repeated measures. Hazard ratios of incident dementia and AD were obtained using semi-parametric proportional hazards models with age as time scale. Over a mean follow-up of 5.4years, 141 subjects developed dementia of which 100 were AD. Overall, no significant association was found between 25(OH)D and cognitive decline, dementia or AD. Higher 25(OH)D concentrations were associated with an increased risk of dementia and AD in women, but not in men. This study does not support a protective effect of vitamin D status on cognitive function. Further research is needed to clarify the relation by sex.

Anaemia and incidence of post stroke dementia

ObjectivesTo assess the impact of anaemia on incidence of post-stroke dementia. Patients and MethodsWe used data from a UK regional stroke register. To be eligible, patient must have survived to discharge and had anaemia by WHO criteria. Dementia status and other prevalent co-morbidities were assessed using ICD-10 codes. Patients were followed till May 2015 (mean follow-up 3.7 years, total person years = 27,769). Hazard Ratio for incident dementia was calculated using Cox-proportional hazards model controlling for potential confounders. Fine and Gray model was additionally constructed using mortality as the competing risk. ResultsA total of 7454 stroke patients were included with mean age SD of 75.912.3 years 50.2 % men). Those with anaemia were older, has higher disability and co-morbidity burden prior to stroke. We observed a large amount of variation in the dementia incidence rates over time and that the hazard ratio increased every year. The significant association between anaemia and dementia incidence was lost after controlling for pre-stroke Modified Rankin score (HR1.17(0.97,1.40)). With every 20 g/dL increase in Hb was associated with a significant reduction in the risk of dementia after adjustment for age, sex, stroke factors and disability but lost significance after adjustment for vascular risk factors. Competing risk analyses showed similar results. ConclusionWhilst we found no evidence of anaemia as a risk factor for post-stroke dementia, the findings may be limited by potential under recognition of post stroke dementia.

Favorable Cardiovascular Health at Young and Middle Ages and Dementia in Older Age-The CHA Study.

BackgroundData are sparse on the association of cardiovascular health (CVH) in younger/middle age with the incidence of dementia later in life.Methods and ResultsWe linked the CHA (Chicago Heart Association Detection Project in Industry) study data, assessed in 1967 to 1973, with 1991 to 2010 Medicare and National Death Index data. Favorable CVH was defined as untreated systolic blood pressure/diastolic blood pressure ≤120/≤80 mm Hg, untreated serum total cholesterol <5.18 mmol/L, not smoking, bone mass index <25 kg/m2, and no diabetes mellitus. International Classification of Diseases, Ninth Revision (ICD‐9) codes and claims dates were used to identify the first dementia diagnosis. Cox models were used to estimate hazard ratios of incident dementia after age 65 years by baseline CVH status. Among 10 119 participants baseline aged 23 to 47 years, 32.4% were women, 9.2% were black, and 7.3% had favorable baseline CVH. The incidence rate of dementia during follow‐up after age 65 was 13.9%. After adjustment, the hazard ratio for incident dementia was lowest in those with favorable baseline CVH and increased with higher risk factor burden (P‐trend<0.001). The hazards of dementia in those with baseline favorable, moderate, and 1‐only high‐risk factor were lower by 31%, 26%, and 20%, respectively, compared with those with ≥2 high‐risk factors. The association was attenuated but remained significant (P‐trend<0.01) when the model was further adjusted for competing risk of death. Patterns of associations were similar for men and women, and for those with a higher and lower baseline education level.ConclusionsIn this large population‐based study, a favorable CVH profile at younger age is associated with a lower risk of dementia in older age.

Association of Retinal Neurodegeneration on Optical Coherence Tomography With Dementia

Retinal structures may serve as a biomarker for dementia, but longitudinal studies examining this link are lacking. To investigate the association of inner retinal layer thickness with prevalent and incident dementia in a general population of Dutch adults. From September 2007 to June 2012, participants from the prospective population-based Rotterdam Study who were 45 years and older and had gradable retinal optical coherence tomography images and at baseline were free from stroke, Parkinson disease, multiple sclerosis, glaucoma, macular degeneration, retinopathy, myopia, hyperopia, and optic disc pathology were included. They were followed up until January 1, 2015, for the onset of dementia. Inner retinal layer thicknesses (ie, retinal nerve fiber layer [RNFL]) and ganglion cell-inner plexiform layer (GC-IPL) thicknesses measured on optical coherence tomography images. Odds ratios and hazard ratios for incident dementia per SD decrease in retinal layer thickness adjusted for age, sex, education, and cardiovascular risk factors. Of 5065 individuals eligible for optical coherence tomography scanning, 3289 (64.9%) (mean [SD] age 68.9 [9.9] years, 1879 [57%] women) were included in the analysis. Of these 3289 individuals, 41 (1.2%) already had dementia. Thinner GC-IPL was associated with prevalent dementia (odds ratio per SD decrease in GC-IPL, 1.37 [95% CI, 0.99-1.90]). No association was found of RNFL with prevalent dementia. During 14 674 person-years of follow-up (mean [SD], 4.5 [1.6] years), 86 individuals (2.6%) developed dementia of whom 68 (2.1%) had Alzheimer disease. Thinner RNFL at baseline was associated with an increased risk of developing dementia (hazard ratio per SD decrease in RNFL, 1.44 [95% CI, 1.19-1.75]), which was similar for Alzheimer disease (hazard ratio, 1.43 [95% CI, 1.15-1.78]). No association was found between GC-IPL thickness and incident dementia (hazard ratio, 1.13 [95% CI, 0.90-1.43]). Thinner RNFL is associated with an increased risk of dementia, including Alzheimer disease, suggesting that retinal neurodegeneration may serve as a preclinical biomarker for dementia.

Combined effects of mild cognitive impairment and slow gait on risk of dementia.

Mild cognitive impairment (MCI) is a high risk of conversion to dementia and gait dysfunction is also a risk for dementia. The goal of the study was to examine if co-occurrence of MCI and slow gait (SG) increases the risk of dementia. A prospective study was conducted in 3937 older adults who did not have dementia at baseline. Participants were classified into groups based on status of MCI and SG: without MCI and SG (control), without MCI and with SG (SG), without SG and with MCI in a single domain (sMCI) or multiple domains (mMCI), sMCI and SG (sMCI + SG), and mMCI and SG (mMCI + SG). Incident dementia was followed monthly. Cox proportional hazards regression models were used to calculate the hazard ratio for incident dementia in each group. During a mean follow-up period of 43 months, 182 subjects had incident dementia. MCI was a risk factor for dementia and SG increased the risk, even after adjusting for covariates (SG: HR = 1.31 (0.81-2.14), 95% CI = 0.276, sMCI: HR = 1.87, 95% CI = 1.21-2.88, p = .005; mMCI: HR = 3.36, 95% CI = 1.98-5.71, p < .001; sMCI + SG: HR = 3.33, 95% CI = 1.92-5.77, p < .001; mMCI + SG: HR = 5.02, 95% CI = 2.75-9.14, p < .001). Co-occurrence of MCI and SG has a high risk of dementia compared to that of each condition alone. Evaluation of both gait and cognition is useful in risk assessment of dementia.

Education and risk of incident dementia during the premotor and motor phases of essential tremor (NEDICES).

Individuals with late-onset essential tremor (ET) (e.g., older adults) seem to have an increased prevalence of mild cognitive impairment and dementia, and a higher risk of incident dementia. It is well-known that education has a protective role against dementia in individuals without a pre-existing neurologic disorder, but evidence regarding the maintenance of this effect during the premotor and motor phases of ET is unknown. Our aim was to determine the influence of education on the risk of dementia in a population-based cohort of ET patients and controls. In a prospective study (Neurological Disorders in Central Spain), participants ≥65 years old were evaluated twice: at baseline (1994–1995) and at follow-up (1997–1998). There were 3 groups: premotor (i.e., participants first diagnosed with incident ET at follow-up), prevalent ET (i.e., participants diagnosed with ET at baseline and at follow-up), and controls. Participants were stratified into lower education (≤primary studies) versus higher education (≥secondary studies) categories. Dementia risk was estimated using Cox proportional-hazards models (higher education control group = reference category). Among the participants, 3878 had a mean duration of follow-up of 3.2 years. Eight (16.7%) of 48 lower education premotor ET patients developed incident dementia versus 1 (3.3%) of 30 higher education premotor ET patients, 9 (7.1%) of 126 lower education prevalent ET patients, 7 (8.8%) of 80 higher education prevalent ET patients, and 92 (4.9%) of 1892 lower education controls (P < 0.001). In comparison to the higher education controls, the adjusted hazard ratios for incident dementia were 5.84 (lower education premotor ET, P < 0.001); 1.36 (higher education premotor ET, P = 0.76); 2.13 (lower education prevalent ET, P = 0.04); 2.79 (higher education prevalent ET, P = 0.01); and 1.66 (lower education controls, P = 0.01). Our results suggest that a higher educational attainment may ameliorate the risk of incident dementia during the premotor phase of ET, but not in the motor phase.

Positive affect and incident dementia among the old

Background: We investigated the association between positive affect and incident dementia among the old. Studies have reportedthe role positive affect has on maintaining health. Still, no longitudinal studies have assessed the association between positiveaffect and incident dementia. Methods: We used the Aichi Gerontological Evaluation Study (AGES) data. Participants were older adults (65 +) who did notreceive benefits from Japan’s public Long-Term Care Insurance System at baseline (N = 14,286) in 6 municipalities. They werefollowed from 2003 to 2007 for dementia onset. Dementia onset was determined according to the criteria used in the Long-TermCare Insurance System. Positive affect was assessed by sub-scales of the Geriatric Depression Scale (GDS-15). Cox hazardproportional models stratified by sex were employed to calculate hazard ratios for incident dementia. Results: Of 14,286 participants (6,813 men and 7,473 women), 333 men (4.9%) and 468 women (6.3%) developed dementiaduring the 4 year follow-up. In age adjusted Cox models, positive affect was significantly associated with lower risk of dementiaboth among men and women. Even after adjusting for health status, health behaviors, social engagement, and low education,positive affect persisted as a significant protector against dementia. Conclusions: We observed a protective role of positive affect against cognitive decline. Factors associated with higher positiveaffect scores were healthier life style, social engagement, and physical health. This implies the importance of maintaining suchactivities to promote cognitive health among the old. In doing so, the role of positive affect merits attention.

Spectrum of cognition short of dementia: Framingham Heart Study and Mayo Clinic Study of Aging.

To understand the neuropsychological basis of dementia risk among persons in the spectrum including cognitive normality and mild cognitive impairment. We quantitated risk of progression to dementia in elderly persons without dementia from 2 population-based studies, the Framingham Heart Study (FHS) and Mayo Clinic Study of Aging (MCSA), aged 70 to 89 years at enrollment. Baseline cognitive status was defined by performance in 4 domains derived from batteries of neuropsychological tests (that were similar but not identical for FHS and MCSA) at cut scores corresponding to SDs of ≤-0.5, -1, -1.5, and -2 from normative means. Participants were characterized as having no cognitive impairment (reference group), or single or multiple amnestic or nonamnestic profiles at each cut score. Incident dementia over the following 6 years was determined by consensus committee at each study separately. The pattern of hazard ratios for incident dementia, rates of incident dementia and positive predictive values across cognitive test cut scores, and number of affected domains was similar although not identical across the FHS and MCSA. Dementia risks were higher for amnestic profiles than for nonamnestic profiles, and for multidomain compared with single-domain profiles. Cognitive domain subtypes, defined by neuropsychologically derived cut scores and number of low-performing domains, differ substantially in prognosis in a conceptually logical manner that was consistent between FHS and MCSA. Neuropsychological characterization of elderly persons without dementia provides valuable information about prognosis. The heterogeneity of risk of dementia cannot be captured concisely with one test or a single definition or cutpoint.