Variable interactions in risk factors for dementia

Current estimates predict 1 in 3 people born today will develop dementia, suggesting a major impact on future population health. As such, research needs to connect specialist clinicians, data scientists and the general public. The In-MINDD project seeks to address this through the provision of a Profiler, a socio-technical information system connecting all three groups. The public interact, providing raw data; data scientists develop and refine prediction algorithms; and clinicians use in-built services to inform decisions. Common across these groups are Risk Factors, used for dementia-free survival prediction. Risk interactions could greatly inform prediction but determining these interactions is a problem underpinned by massive numbers of possible combinations. Our research employs a machine learning approach to automatically select best performing hyperparameters for prediction and learns variable interactions in a non-linear survival-analysis paradigm. Demonstrating effectiveness, we evaluate this approach using longitudinal data with a relatively small sample size

Variable interactions in risk factors for dementia

Current estimates predict 1 in 3 people born today will develop dementia, suggesting a major impact on future population health. As such, research needs to connect specialist clinicians, data scientists and the general public. The In-MINDD project seeks to address this through the provision of a Profiler, a socio-technical information system connecting all three groups.\ud The public interact, providing raw data; data scientists develop and refine prediction algorithms; and clinicians use in-built services to inform decisions. Common across these groups are Risk Factors, used for dementia-free survival prediction. Risk interactions could greatly inform prediction but determining these interactions is a problem underpinned by massive numbers of possible combinations. Our research employs a machine learning approach to automatically select best performing hyperparameters for prediction and learns variable interactions in a non-linear survival-analysis paradigm. Demonstrating effectiveness, we evaluate this approach using longitudinal data with a relatively small sample size

Predeath Grief, Resourcefulness, and Perceived Stress Among Caregivers of Partners With Young-Onset Dementia

More than 200,000 Americans are currently diagnosed with young-onset dementia (YOD). YOD is dementia diagnosed prior to the age of 65. Most persons of YOD are cared for by their partners. Using the theoretical framework of Resilience Theory, this cross-sectional, correlational study examined the moderating effects of personal and social resourcefulness on the relationship between predeath grief and perceived stress among 104 YOD caregiving partners (life partners/spouses) using an online survey platform. Results indicated a large positive correlation between predeath grief and caregiver perceived stress (r = .65; p \u3c .001). Together predeath grief, personal resourcefulness and social resourcefulness explained 51.5% of the variance in perceived stress. Personal resourcefulness did not moderate the relationship. Social resourcefulness did positively moderate this relationship between predeath grief and perceived stress. These findings allow for a better understanding of the caregiving experience for a partner with YOD and creates opportunities for future research studies

Effects of Positive Thinking on Dementia Caregivers’ Burden and Care-Recipients’ Behavioral Problems

Most dementia care is provided at home by family members. This caregiving places an additional burden on the family members, which can negatively impact their physical and psychological well-being. The caregivers’ burden can also contribute to behavioral problems in the care-recipients. The purpose of this study was to examine the mediating/moderating effects of positive thinking (PT) on the relationship between caregivers’ burden (embarrassment/anger, patient’s dependency, and self-criticism) and their care-recipients’ behavioral problems (memory, depression, and disruption) in a sample of 100 dementia caregivers. Results indicated that caregivers’ embarrassment, self-criticism, and perception of patient dependency predicts depression in care-recipients, and these relationships are moderated by PT. Results also indicated that as PT increases, the relationship between embarrassment and disruption goes down as well as does the relationship between self-criticism and depression. The study provided direction for the development of a PT training intervention to help caregivers to combat their burden

Use of Antihypertensives, Blood Pressure, and Estimated Risk of Dementia in Late Life

ImportanceThe utility of antihypertensives and ideal blood pressure (BP) for dementia prevention in late life remains unclear and highly contested.ObjectivesTo assess the associations of hypertension history, antihypertensive use, and baseline measured BP in late life (age >60 years) with dementia and the moderating factors of age, sex, and racial group.Data Source and Study SelectionLongitudinal, population-based studies of aging participating in the Cohort Studies of Memory in an International Consortium (COSMIC) group were included. Participants were individuals without dementia at baseline aged 60 to 110 years and were based in 15 different countries (US, Brazil, Australia, China, Korea, Singapore, Central African Republic, Republic of Congo, Nigeria, Germany, Spain, Italy, France, Sweden, and Greece).Data Extraction and SynthesisParticipants were grouped in 3 categories based on previous diagnosis of hypertension and baseline antihypertensive use: healthy controls, treated hypertension, and untreated hypertension. Baseline systolic BP (SBP) and diastolic BP (DBP) were treated as continuous variables. Reporting followed the Preferred Reporting Items for Systematic Review and Meta-Analyses of Individual Participant Data reporting guidelines.Main Outcomes and MeasuresThe key outcome was all-cause dementia. Mixed-effects Cox proportional hazards models were used to assess the associations between the exposures and the key outcome variable. The association between dementia and baseline BP was modeled using nonlinear natural splines. The main analysis was a partially adjusted Cox proportional hazards model controlling for age, age squared, sex, education, racial group, and a random effect for study. Sensitivity analyses included a fully adjusted analysis, a restricted analysis of those individuals with more than 5 years of follow-up data, and models examining the moderating factors of age, sex, and racial group.ResultsThe analysis included 17 studies with 34 519 community dwelling older adults (20 160 [58.4%] female) with a mean (SD) age of 72.5 (7.5) years and a mean (SD) follow-up of 4.3 (4.3) years. In the main, partially adjusted analysis including 14 studies, individuals with untreated hypertension had a 42% increased risk of dementia compared with healthy controls (hazard ratio [HR], 1.42; 95% CI 1.15-1.76; P = .001) and 26% increased risk compared with individuals with treated hypertension (HR, 1.26; 95% CI, 1.03-1.53; P = .02). Individuals with treated hypertension had no significant increased dementia risk compared with healthy controls (HR, 1.13; 95% CI, 0.99-1.28; P = .07). The association of antihypertensive use or hypertension status with dementia did not vary with baseline BP. There was no significant association of baseline SBP or DBP with dementia risk in any of the analyses. There were no significant interactions with age, sex, or racial group for any of the analyses.Conclusions and RelevanceThis individual patient data meta-analysis of longitudinal cohort studies found that antihypertensive use was associated with decreased dementia risk compared with individuals with untreated hypertension through all ages in late life. Individuals with treated hypertension had no increased risk of dementia compared with healthy controls

Utilization of cognitive support in episodic free recall as a function of apolipoprotein E and vitamin B12 or folate among adults aged 75 years and older

Apolipoprotein E (APOE), vitamin B12, and folate were examined in relation to free recall among 167 community-based older adults. Cognitive support at encoding and retrieval was also taken into account. Participants were classified as APOE e4 or non-e4 allele carriers and as either low or normal vitamin B12 or folate status. A significant association was identified between low vitamin B12 and the e4 genotype in respect to free recall, but only in circumstances of low cognitive support. This result remained after removing dementia cases that occurred up to 6 years after testing. A similar, but nonsignificant, trend was evident in relation to folate. The research is discussed with reference to vulnerability models and genetic influences on brain reserves

Genes of the serotonergic and dopaminergic pathways and their interaction affect the expression of Behavioural and Psychological Symptoms in Dementia (BPSD).

Although there is evidence for the involvement of genes of serotonergic and dopaminergic systems in the manifestation of the Behavioural and Psychological Symptoms in Dementia (BPSD), genetic association studies are contradictory. We used 1008 probable AD patients from the UK and applied a Multiple Indicators Multiple Causes (MIMIC) approach to investigate the effect of 11 polymorphisms in the serotonergic and dopaminergic systems, on four behavioural sub-phenotypes, namely "psychosis"," moods", "agitation" and "behavioural dyscontrol", as well as on 12 NPI items. Significant findings included the association of DRD1 A48G with "psychosis" (p=0.037), the association of DAT1 VNTR with "agitation" (p=0.006) and the association of DRD4 with "moods" sub-phenotype (p=0.008). In addition, associations were identified between DRD1 A48G and DAT1 VNTR with aberrant motor behaviour (AMB) symptoms (p=0.001 and p=0.015 respectively), between DRD4 and sleep disturbances (p=0.018) and between 5HTTLPR and apathy (p=0.033). Finally, significant interactions were observed between COMT Val158Met and 5HTTLPR with "psychosis" (p=0.026), between HTTLPR and STin2 with "psychosis" (p=0.005), between DAT1 3'UTR VNTR and COMT Val158Met with "agitation" (p=0.0001) and between DAT1 3'UTR VNTR and 5HTTLPR with the "moods" factor (p=0.0027). The complexity of the interrelations between genetic variation, behavioural symptoms and clinical variables was efficiently captured by this MIMIC model