Promoting diverse perspectives: Addressing health disparities related to Alzheimer's and all dementias

Dementia research lacks appropriate representation of diverse groups who often face substantial adversity and greater risk of dementia. Current research participants are primarily well-resourced, non-Hispanic White, cisgender adults who live close to academic medical centers where much of the research is based. Consequently, the field faces a knowledge gap about Alzheimer's-related risk factors in those other groups. The Alzheimer's Association hosted a virtual conference on June 14-16, 2021, supported in part by the National Institute on Aging (R13 AG072859-01), focused on health disparities. The conference was held entirely online and consisted of 2 days of core programming and a day of focused meetings centered on American Indian and Alaska Natives and on LGBTQIA+ populations. Over 1300 registrants attended discussions focused on the structural and systemic inequities experienced across diverse groups, as well as ways to investigate and address these inequities.

Alzheimer's disease research progress in Australia: The Alzheimer's Association International Conference Satellite Symposium in Sydney

The Alzheimer's Association International Conference held its sixth Satellite Symposium in Sydney, Australia in 2019, highlighting the leadership of Australian researchers in advancing the understanding of and treatment developments for Alzheimer's disease (AD) and other dementias. This leadership includes the Australian Imaging, Biomarker, and Lifestyle Flagship Study of Ageing (AIBL), which has fueled the identification and development of many biomarkers and novel therapeutics. Two multimodal lifestyle intervention studies have been launched in Australia; and Australian researchers have played leadership roles in other global studies in diverse populations. Australian researchers have also played an instrumental role in efforts to understand mechanisms underlying vascular contributions to cognitive impairment and dementia; and through the Women's Healthy Aging Project have elucidated hormonal and other factors that contribute to the increased risk of AD in women. Alleviating the behavioral and psychological symptoms of dementia has also been a strong research and clinical focus in Australia.

Using Genetic Information to Explore Whether Preclinical Alzheimer’s Disease Affects Hearing Difficulty

Underlying AD-related neurodegeneration or shared risk factors may influence hearing loss; in an innovative approach we tested whether genetic risk for AD also influences functional hearing loss. We studied 401,084 UK Biobank participants aged 40-70, with Caucasian genetic ancestry, and enrolled 2007-2010. Participants self-reported hearing difficulty and were followed for AD diagnosis until 2018. A genetic risk score for AD (AD-GRS) was calculated as a weighted sum of 23 AD risk variants. In age-, sex-, and genetic ancestry- adjusted models higher AD-GRS was associated with problem hearing in ages 60+(OR= 1.03; 95%CI:1.00, 1.05), but not ages <60 (p>0.05). Using the AD-GRS as an instrumental variable for AD diagnosis, we estimated that incipient AD increased probability of difficulty hearing at enrollment by 45% (95%CI: 1%, 93%). Higher AD-GRS was associated with slightly higher odds of hearing difficulty in older adults. Genetics that predispose for AD also influence late-life hearing difficulty.

Exploring the Risk and Protective Factors for the Mental Health of Sexual Minority Asian Americans

This study characterizes the mental health of Asian American older adults (aged 60+) who identify as sexual minorities (SM or lesbian, gay, bisexual) and compare to their non-Asian American and non-SM counterparts. Data were from the Research Program on Genes, Environment and Health (Aged 60+; N=185,478), a representative sample of healthcare members from Northern California. It includes SM (N=447) and heterosexual/non-SM (N=15,772) older adults who identify as Asian American (Chinese, Japanese, Filipino, and South Asian) and non-Asian American SM (N=3,890). Rates of dementia, anxiety, and PTSD were similar for both SM and non-SM Asian Americans. However, older lesbian and gay Asian Americans were more likely to have a depression diagnosis (30% vs. 18%, p=0.002) compared to non-SM. Overall, mental health outcomes were lower for Asian American SM compared to non-Asian American SM. We discuss need for understanding protective factors for mental health and implications for future interventions.

Perspective on the "African American participation in Alzheimer disease research: Effective strategies" workshop, 2018

The Washington University School of Medicine Knight Alzheimer Disease Research Center's "African American Participation in Alzheimer Disease Research: Effective Strategies" Workshop convened to address a major limitation of the ongoing scientific progress regarding Alzheimer's disease and related dementias (ADRD): participants in most ADRD research programs overwhelmingly have been limited to non-Hispanic white persons, thus precluding knowledge as to how ADRD may be represented in non-white individuals. Factors that may contribute to successful recruitment and retention of African Americans into ADRD research were discussed and organized into actionable next steps as described within this report.

World-Wide FINGERS Network: A global approach to risk reduction and prevention of dementia

Reducing the risk of dementia can halt the worldwide increase of affected people. The multifactorial and heterogeneous nature of late-onset dementia, including Alzheimer’s disease (AD), indicates a potential impact of multidomain lifestyle interventions on risk reduction. The positive results of the landmark multidomain Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) support such an approach. The World-Wide FINGERS (WW-FINGERS), launched in 2017 and including over 25 countries, is the first global network of multidomain lifestyle intervention trials for dementia risk reduction and prevention. WW-FINGERS aims to adapt, test, and optimize the FINGER model to reduce risk across the spectrum of cognitive decline—from at-risk asymptomatic states to early symptomatic stages—in different geographical, cultural, and economic settings. WW-FINGERS aims to harmonize and adapt multidomain interventions across various countries and settings, to facilitate data sharing and analysis across studies, and to promote international joint initiatives to identify globally implementable and effective preventive strategies.

First translational 'Think Tank' on cerebrovascular disease, cognitive impairment and dementia

As the human population continues to age, an increasing number of people will exhibit significant deficits in cognitive function and dementia. It is now recognized that cerebrovascular, metabolic and neurodegenerative diseases all play major roles in the evolution of cognitive impairment and dementia. Thus with our more recent recognition of these relationships and our need to understand and more positively impact on this world health problem, "The Leo and Anne Albert Charitable Trust" (Gene Pranzo, Trustee with significant support from Susan Brogan, Meeting Planner) provided generous support for this inaugural international workshop that was held from April 13-16, 2015 at the beautiful Ritz Carlton Golf Resort in North Naples, Florida. Researchers from SUNY Downstate Medical Center, Brooklyn, NY organized the event by selecting the present group of translationally inclined preclinical, clinical and population scientists focused on cerebrovascular disease (CVD) risk and its progression to vascular cognitive impairment (VCI) and dementia. Participants at the workshop addressed important issues related to aging, cognition and dementia by: (1) sharing new data, information and perspectives that intersect vascular, metabolic and neurodegenerative diseases, (2) discussing gaps in translating population risk, clinical and preclinical information to the progression of cognitive loss, and (3) debating new approaches and methods to fill these gaps that can translate into future therapeutic interventions. Participants agreed on topics for group discussion prior to the meeting and focused on specific translational goals that included promoting better understanding of dementia mechanisms, the identification of potential therapeutic targets for intervention, and discussed/debated the potential utility of diagnostic/prognostic markers. Below summarizes the new data-presentations, concepts, novel directions and specific discussion topics addressed by this international translational team at our "First Leo and Anne Albert Charitable Trust 'Think Tank' VCI workshop".

Early adult to midlife cardiovascular risk factors and cognitive function

BACKGROUND

Studies have linked midlife and late-life cardiovascular risk factors (CVRFs) to cognitive function, yet little is known about CVRF exposure in early adulthood and subsequent cognitive function. In addition, most studies rely on single assessments of CVRFs, which may not accurately reflect long-term exposure. We sought to determine the association between cumulative exposure to CVRFs from early to middle adulthood and cognitive function at midlife.

METHODS AND RESULTS

In a prospective study of 3381 adults (age, 18-30 years at baseline) with 25 years of follow-up, we assessed cognitive function at year 25 (2010-2011) with the Digit Symbol Substitution Test, Stroop Test, and Rey Auditory Verbal Learning Test analyzed with standardized z scores. The primary predictor was 25-year cumulative exposure estimated by areas under the curve for resting systolic and diastolic blood pressures, fasting blood glucose, and total cholesterol. Higher cumulative systolic and diastolic blood pressures and fasting blood glucose were consistently associated with worse cognition on all 3 tests. These associations were significant primarily for exposures above recommended guidelines; cognitive test z scores were between 0.06 and 0.30 points less, on average, for each 1-SD increase in risk factor area under the curve after adjustment for age, race, sex, and education (P<0.05 for all). Fewer significant associations were observed for cholesterol.

CONCLUSIONS

Cumulative exposure to CVRFs from early to middle adulthood, especially above recommended guidelines, was associated with worse cognition in midlife. The meaning of this association and whether it warrants more aggressive treatment of CVRFs earlier in life require further investigation.

The association of bone mineral density and depression in an older population

OBJECTIVE

To evaluate the association between bone mineral density (BMD) and measurements of depression in an older population.

DESIGN

Population-based, cross-sectional study.

SETTING

Study subjects were participants in the Cardiovascular Health Study (CHS), a longitudinal, long-term, follow-up study, at the University of California Davis (Sacramento, California) and the University of Pittsburgh (Pittsburgh, Pennsylvania) clinical centers.

PARTICIPANTS

A random sample of 1,566 Medicare enrollees age 65 and older enrolled in the CHS.

MEASUREMENTS

Total hip BMD, measured using dual energy x-ray absorptiometry (DEXA), after adjustment for multiple covariates, was compared with depression evaluated with the Center for Epidemiological Studies 10-item Depression Scale (CES-Dm). Risk factors for osteoporosis were compared in depressed and nondepressed participants. Potential correlates were entered into a regression model. Depression scores were compared in normal, osteopenic, and osteoporotic individuals.

RESULTS

Sixteen percent of participants were clinically depressed; 9% had BMDs in the osteoporotic range. Mean BMD was 40 mg/cm2 lower in those with clinical depression. High CES-Dm scores were associated with lower BMD (P < .001) when adjusted for body mass index (BMI), age, kilocalories of activity, estrogen use, gender, race, smoking and drinking. When stratified by race, this remained true for all Caucasians (P < .01), all African Americans (P < .05), and when stratified by race and gender the association remained only for all Caucasian women (P < .001). In women and Caucasian men there was an increase in depression scores among individuals with osteoporotic-range BMDs.

CONCLUSIONS

A significant association was found between BMD and depressive symptoms after adjustment for osteoporosis risk factors. In Caucasians, depressive symptoms were associated with both osteoporotic and osteopenic levels of BMD. Causality cannot be ascribed, with only one measurement of BMD. We postulate that there may be an unmeasured third factor, such as an endogenous steroid, that is responsible for both low BMD and depression.

Effects of albumin and apolipoprotein C-II on the acyl-chain specificity of lipoprotein lipase catalysis

In this study we used monoacid triacylglycerols of various acyl-chain lengths as substrates for probing the active-site structure and substrate specificity of lipoprotein lipase (LPL). An unexpected finding was that the albumin ligand binding site is accessible not only to long-chain fatty acids for its recognized functional role as a fatty acid acceptor, but also to short- and medium-chain monoacid triacylglycerol substrates. The observed striking inhibitory effect (99%) of albumin on the LPL-catalyzed hydrolysis of trihexanoylglycerol is probably the result of the high affinity interaction of albumin with this substrate. Spectrophotometric analyses indicated that there is one high affinity binding site per albumin molecule (apparent KD = 1.8 +/- 0.9 microM) for the interaction with trihexanoylglycerol. Despite LPL acyl-chain specificity being obscured by the substrate binding effect of albumin, a systematic study of the lipolysis reaction under various assay conditions demonstrated that tributyroylglycerol represents the best substrate for LPL, and the preferential order of LPL catalysis for both the basal and apoC-II-activated activities is: C4 > C6 > C8 > C10 > C12 > C18:1. In some assay conditions, the presence of albumin affects the above-mentioned order, which can be attributed to substrate binding by albumin, rather than an alteration in the specificity of LPL. The synergistic effect of apoC-II and albumin resulted in the preferential activation of LPL for the hydrolysis of long-chain triacylglycerols. Even with optimal assay conditions for the hydrolysis of long chain triacylglycerols, there is still a preferential reactivity of LPL with short- and medium-chain triacylglycerols.