Dementia Prevention Guidelines Should Explicitly Mention Deprivation

The Mediating Role of Lifestyle Activities in the Association Between Social Deprivation and Cognition in Older Adulthood: Results From the Health and Retirement (HRS) Study

Objectives: We aimed to investigate the mediating role of lifestyle activities in the association between social deprivation and cognition. Methods: To investigate, we analysed data of 3867 respondents (Mean Age: 73.37, SD: 5.57) in the U.S. Health and Retirement Study (HRS) using growth curve and path analysis, adjusted for demographic and health covariates. Results: Being in the high (vs. moderate) Social Deprivation Index group was associated with lower cognition scores (β = -2.63, [95 % CI: -2.90, -2.36]). Conversely, higher (vs. lower) Lifestyle Index scores were associated with higher cognition scores (β = 1.17, [95 % CI: 0.72, 1.63]). In mediation analysis, the Lifestyle Index score explained 27 % of the association of So Dep Index group on cognition at the final follow-up. Discussion: While lifestyle activities did mediate the association between social deprivation and cognition, factors not investigated accounted for the majority of the variation. These may include systemic disadvantages.

Experimental laboratory models as tools for understanding modifiable dementia risk

Experimental laboratory research has an important role to play in dementia prevention. Mechanisms underlying modifiable risk factors for dementia are promising targets for dementia prevention but are difficult to investigate in human populations due to technological constraints and confounds. Therefore, controlled laboratory experiments in models such as transgenic rodents, invertebrates and in vitro cultured cells are increasingly used to investigate dementia risk factors and test strategies which target them to prevent dementia. This review provides an overview of experimental research into 15 established and putative modifiable dementia risk factors: less early-life education, hearing loss, depression, social isolation, life stress, hypertension, obesity, diabetes, physical inactivity, heavy alcohol use, smoking, air pollution, anesthetic exposure, traumatic brain injury, and disordered sleep. It explores how experimental models have been, and can be, used to address questions about modifiable dementia risk and prevention that cannot readily be addressed in human studies. HIGHLIGHTS: Modifiable dementia risk factors are promising targets for dementia prevention. Interrogation of mechanisms underlying dementia risk is difficult in human populations. Studies using diverse experimental models are revealing modifiable dementia risk mechanisms. We review experimental research into 15 modifiable dementia risk factors. Laboratory science can contribute uniquely to dementia prevention.

Frailty trajectories preceding dementia: an individual-level analysis of four cohort studies in the United States and United Kingdom

Frailty may represent a modifiable risk factor for dementia, but the direction of that association remains uncertain. We investigated frailty trajectories in the years preceding dementia onset using data from 23,672 participants (242,760 person-years of follow-up, 2,906 cases of incident dementia) across four cohort studies in the United States and United Kingdom. Bayesian non-linear models revealed accelerations in frailty trajectories 4-9 years before incident dementia. Among participants whose time between frailty measurement and incident dementia exceeded that prodromal period, frailty remained positively associated with dementia risk (adjusted hazard ratios ranged from 1.20 [95% confidence interval, CI = 1.15-1.26] to 1.43 [95% CI = 1.14-1.81]). This observational evidence suggests that frailty increases dementia risk independently of any reverse causality. These findings indicate that frailty measurements can be used to identify high-risk population groups for preferential enrolment into clinical trials for dementia prevention and treatment. Frailty itself may represent a useful upstream target for behavioural and societal approaches to dementia prevention.

If deprivation worsens dementia outcomes, stimulation should improve them

It is still not known what causes Alzheimer's Disease (AD). In this period of uncertainty, an emerging literature on risk factors suggests that the concept of "stimulation" is a useful pragmatic tool both before and after diagnosis to improve cognitive health. Before diagnosis of AD, stimulation of the brain through education, exercise, and social stimulation provides fortification against later cognitive decline. After diagnosis, specific electrical stimulation of brain circuits may protect cognitive function, and non-specific stimulation through different kinds of environmental enrichment may help to compensate for cognitive decline. Pragmatic guidelines are offered here to maximise enabling stimulation (physical, cognitive, and social activity) and minimise disabling stimulation across the lifetime (e.g. stress, pollution, and poor diet). However, much deeper structural changes in society are needed to struggle against socioeconomic and environmental deprivation and the inaccessibility of education for women across the globe.