The feasibility of a multidomain dementia risk reduction randomised controlled trial for people experiencing cognitive decline: the Body, Brain, Life for Cognitive Decline (BBL-CD)

OBJECTIVES

To evaluate the feasibility of a proof-of-concept multidomain dementia risk reduction intervention.

METHOD

An 8-week, parallel-group RCT, focused on increasing adherence to lifestyle domains of Mediterranean diet (MeDi), Physical Activity (PA), and Cognitive Engagement (CE). Feasibility was evaluated against the Bowen Feasibility Framework objectives of: Acceptability of the intervention, compliance with the protocol, and efficacy of the intervention to change behaviour in the three domains of interest.

RESULTS

High acceptability of the intervention was demonstrated through a participant retention rate of 80.7% (Intervention: 84.2%; Control: 77.4%). Compliance to the protocol was strong with 100% of participants completing all educational modules and all MeDi and PA components, with 20% compliance for CE. Linear mixed models demonstrated efficacy to change behaviour through significant effects of adherence to MeDi (χ2 = 16.75, df = 3, p < .001) and CE (χ2 = 9.83, df = 3, p =.020), but not PA (χ2 = 4.48, df = 3, p =.211).

CONCLUSION

Overall the intervention was shown to be feasible. Recommendations for future trials in this area are: The implementation of practical, one-on-one sessions as they are more effective than passive education at eliciting behaviour change; use of booster sessions to increase likelihood of lifestyle changes being sustained; and collection of qualitative data to identify barriers to change.

Cost-Effectiveness of Dementia Prevention Interventions

BACKGROUND

Assessment of cost-effectiveness of interventions to address modifiable risk factors associated with dementia requires estimates of long-term impacts of these interventions which are rarely directly available and must be estimated using a range of assumptions.

OBJECTIVES

To test the cost-effectiveness of dementia prevention measures using a methodology which transparently addresses the many assumptions required to use data from short-term studies, and which readily incorporates sensitivity analyses.

DESIGN

We explore an approach to estimating cost-effective prices which uses aggregate data including estimated lifetime costs of dementia, both financial and quality of life, and incorporates a range of assumptions regarding sustainability of short- term gains and other parameters.

SETTING

The approach is addressed in the context of the theoretical reduction in a range of risk factors, and in the context of a specific small-scale trial of an internet-based intervention augmented with diet and physical activity consultations.

MEASUREMENTS

The principal outcomes were prices per unit of interventions at which interventions were cost-effective or cost-saving.

RESULTS

Taking a societal perspective, a notional intervention reducing a range of dementia risk-factors by 5% was cost-effective at $A460 per person with higher risk groups at $2,148 per person. The on-line program costing $825 per person was cost-effective at $1,850 per person even if program effect diminished by 75% over time.

CONCLUSIONS

Interventions to address risk factors for dementia are likely to be cost-effective if appropriately designed, but confirmation of this conclusion requires longer term follow-up of trials to measure the impact and sustainability of short-term gains.

Oxidative stress, inflammation and mild cognitive impairment

Introduction

Oxidative stress (OS) and inflammation are processes known to be implicated in neurodegeneration. Moreover, risk factors for dementia (depression, obesity, sedentary lifestyle, diabetes, etc.) are associated with up-regulation of pro-inflammatory cytokines. OS has been found in animal models to contribute to cerebral amyloid angiopathy. However, investigations of the associations between OS, inflammation and MCI, typically in small clinical samples have produced mixed results.

Objectives

Clarify associations, between OS, inflammation and MCI in a large cohort of community-living individuals.

Methods

Cognitively healthy individuals (n = 211, 44% female, 75.2 years) and with MCI (n = 23, 44% female, 75.2 years) from a population sample were included. MCI diagnosis was established based on a detailed neuropsychological assessment. Inflammatory (IL1b, IL4, IL6, IL8, IL10, TNF-a) and OS (total anti-oxidants, NO, neopterin) markers were assessed in plasma samples. Associations between biomarkers, MMSE, and MCI status were tested with multiple linear and logistic regression analyses.

Results

Univariate analyses showed that log IL4 (estimate: −0.175, SE: 0.085, P = 0.041) and NO (estimate: 0.015, SE: 0.006, P = 0.017) were the only markers associated with MMSE scores. MCI status was predicted by log IL4 (estimate: 0.822, SE: 0.357, P = 0.021) and total anti-oxidants (estimate: −0.007, SE: 0.003, P = 0.014). Controlling for pro-inflammatory conditions (T2D, BMI, depression, hypertension) removed the associations with inflammation but not with OS.

Conclusions

These results indicate that increased systemic inflammation and increased OS were associated with lower MMSE scores and higher odds of having MCI. This confirms that systemic pro-inflammatory processes are associated with impaired cognition and should be specifically considered in treatment and risk-reduction interventions.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Oxidative stress, inflammation and risk of neurodegeneration in a population sample

BACKGROUND AND PURPOSE

Inflammation and oxidative stress (OS) have been clearly linked to neurodegeneration. However, studies investigating the associations between peripheral markers of inflammation and cognitive decline have produced mixed results. This is possibly due to the fact that markers are typically tested individually despite the fact that biologically they function interactively. Thus, the aim of this study was to investigate the association between a combination of OS/inflammation markers and outcomes including mild cognitive impairment (MCI) diagnosis, cognitive decline and hippocampal atrophy.

METHODS

Oxidative stress/inflammation status was assessed in 380 older community-living individuals. Thirteen blood markers were assayed. Principal component analysis (PCA) of all markers was conducted to identify the more salient inflammatory components. Associations between significant principal components, MCI diagnosis, previous change in Mini-Mental State Examination (MMSE) score and hippocampal atrophy were investigated through logistic and linear multiple regression.

RESULTS

Two factors (PC1 and PC2) reflecting predominantly broad pro-inflammatory activity and two factors (PC3 and PC4) reflecting predominantly OS activity were identified by PCA analysis. PC3 and PC4 were predictive of MCI. PC3 was also predictive of prior MMSE change. PC1, PC2 and PC3 were significantly associated with hippocampal atrophy.

CONCLUSIONS

Combined analysis of complex and interacting biomarkers revealed a protective association between antioxidant activity and MCI that is consistent with lifestyle factors shown to reduce risk of cognitive decline. OS and broad systemic inflammation were also found to be associated with hippocampal atrophy further highlighting the benefits of the PCA methodology applied in this study.

Trajectories of BMI change impact glucose and insulin metabolism

BACKGROUND AND AIMS

The aim of this study was to examine, in a community setting, whether trajectory of weight change over twelve years is associated with glucose and insulin metabolism at twelve years.

METHODS AND RESULTS

Participants were 532 community-living middle-aged and elderly adults from the Personality and Total Health (PATH) Through Life study. They spanned the full weight range (underweight/normal/overweight/obese). Latent class analysis and multivariate generalised linear models were used to investigate the association of Body Mass Index (BMI, kg/m²) trajectory over twelve years with plasma insulin (μlU/ml), plasma glucose (mmol/L), and HOMA2 insulin resistance and beta cell function at follow-up. All models were adjusted for age, gender, hypertension, pre-clinical diabetes status (normal fasting glucose or impaired fasting glucose) and physical activity. Four weight trajectories were extracted; constant normal (mean baseline BMI = 25; follow-up BMI = 25), constant high (mean baseline BMI = 36; follow-up BMI = 37), increase (mean baseline BMI = 26; follow-up BMI = 32) and decrease (mean baseline BMI = 34; follow-up BMI = 28). At any given current BMI, individuals in the constant high and increase trajectories had significantly higher plasma insulin, greater insulin resistance, and higher beta cell function than those in the constant normal trajectory. Individuals in the decrease trajectory did not differ from the constant normal trajectory. Current BMI significantly interacted with preceding BMI trajectory in its association with plasma insulin, insulin resistance, and beta cell function.

CONCLUSION

The trajectory of preceding weight has an independent effect on blood glucose metabolism beyond body weight measured at any given point in time.

Combining Geospatial Analysis with Dementia Risk Utilising General Practice Data: A Systematic Review

Geographical information systems (GIS) and geospatial analysis techniques will help to identify significant dementia risk clusters (hotspots) across communities and will enable policy makers to target prevention interventions to the right place. This review synthesises the published literature on geospatial analysis techniques for quantifying and mapping dementia risk, and reviews available dementia risk assessment tools. A systematic literature review was undertaken in four medical and life sciences databases (PubMed, Cochrane Central, Embase, and Web of Sciences) from their inception to March 2017 for all articles relating to dementia. The search terms included: 'dementia', 'Alzheimer's disease', 'general practice database', 'family physician', 'AD risk assessment tools', 'Geographical Information Systems' and 'geospatial analysis', 'geographical variation' and 'spatial variation'. To date, most geospatial studies on dementia have been carried out retrospectively using population based data. An alternative approach is utilisation of a rich source of general practice (family physician) databases to predict dementia risk based on available dementia risk assessment tools. In conclusion, the estimated risks of dementia can thus be geo-attributed and mapped at a small scale using geographical information systems and geospatial analysis techniques to identify dementia risk clusters across the communities and refine our understanding of the interaction between socio-demographic and environmental factors, and dementia risk clusters.   .

Body mass index is associated with cortical thinning with different patterns in mid- and late-life

OBJECTIVE

High BMI at midlife is associated with increased risk of dementia as well as faster decline in cognitive function. In late-life, however, high BMI has been found to be associated with both increased and decreased dementia risk. The objective of this study was to investigate the neural substrates of this age-related change in body mass index (BMI) risk.

METHODS

We measured longitudinal cortical thinning over the whole brain, based on magnetic resonance imaging scans for 910 individuals aged 44-66 years at baseline. Subjects were sampled from a large population study (PATH, Personality and Total Health through Life). After attrition and exclusions, the final analysis was based on 792 individuals, including 387 individuals aged 60-66 years and 405 individuals aged 44-49 years. A mixed-effects model was used to test the association between cortical thinning and baseline BMI, as well as percentage change in BMI.

RESULTS

Increasing BMI was associated with increased cortical thinning in posterior cingulate at midlife (0.014 mm kg^-1 m^-2, confidence interval; CI=0.005, 0.023, P<0.05 false discovery rate (FDR) corrected). In late-life, increasing BMI was associated with reduced cortical thickness, most prominently in the right supramarginal cortex (0.010 mm kg^-1 m^-2, CI=0.005-0.016, P<0.05 FDR corrected), as well as frontal regions. In late-life, decreasing BMI was also associated with increased cortical thinning, including right caudal middle frontal cortex (0.014 mm kg^-1 m^-2 (CI=0.006-0.023, P<0.05 FDR corrected).

CONCLUSIONS

The pattern of cortical thinning-in association with increasing BMI at both midlife and late-life-is consistent with known obesity-related dementia risk. Increased cortical thinning in association with decreasing BMI at late-life may help explain the 'obesity paradox', where high BMI in midlife appears to be a risk factor for dementia, but high BMI in late-life appears, at times, to be protective.

Online memory screening--are older adults interested and can it work?

Subjective memory concerns are common in older adults and may prompt the use of web-based cognitive screening. Websites which purport to provide memory screening are numerous and can influence health behaviours; however there is currently limited evidence regarding their validity. The current research aims to assess potential user's attitudes and motivations regarding online cognitive screening and to evaluate the preliminary evidence for the feasibility and validity of two subjective online cognitive measures. The sample consisted of community-based older adults, 30 with, and 30 without, memory concerns. Participants rated their likelihood of their accessing online cognitive screening and gave rationales. Participants' performance on objective pen and paper measures of cognition was compared to performance on subjective online screening measures. The majority of participants indicated they would access online cognitive screening. A total of 100% of participants were able to use the online tools without assistance. None of the online measures was positively associated with the pen and paper screening measures. Anxiety and depression were significantly associated with subjective memory concerns. This study provided no supporting evidence for the validity of either subjective online screening measure assessed. Anxiety and depression were significantly associated with subjective cognition, indicating that, although they may not predict objective cognition, complaints about memory in older adults should be taken seriously by health professionals.

Body mass index in midlife and late-life as a risk factor for dementia: a meta-analysis of prospective studies

The relationship between body mass index (BMI) (in midlife and late-life) and dementia was investigated in meta-analyses of 16 articles reporting on 15 prospective studies. Follow-ups ranged from 3.2 to 36.0 years. Meta-analyses were conducted on samples including 25 624 participants evaluated for Alzheimer's disease (AD), 15 435 participants evaluated for vascular dementia (VaD) and 30 470 followed for any type of dementia (Any Dementia). Low BMI in midlife was associated with 1.96 [95% confidence interval (CI): 1.32, 2.92] times the risk of developing AD. The pooled relative risks for AD, VaD and Any Dementia for overweight BMI in midlife compared with normal BMI were 1.35 (95% CI:1.19, 1.54), 1.33 (95% CI: 1.02, 1.75) and 1.26 (95% CI: 1.10, 1.44), respectively. The pooled relative risks of AD and Any Dementia for obese BMI in midlife compared to normal BMI were 2.04 (95% CI: 1.59, 2.62) and 1.64 (95% CI: 1.34, 2.00), respectively. Continuous BMI in late-life was not associated with dementia. Small numbers of studies included in pooled analyses reduce generalizability of findings, and emphasize the need for publication of additional findings. We conclude that underweight, overweight and obesity in midlife increase dementia risk. Further research evaluating late-life BMI and dementia is required.