Research

Background

Alzheimer’s disease (AD) is a global crisis facing the aging population and society as a whole. Despite studies suggesting that blacks may be at greater risk of developing AD, with 2-3 times higher prevalence rate of cognitive impairment than whites, there have been few studies investigating health disparities, and blacks have been underrepresented in many prominent U.S. AD biomarker studies and clinical trials. The current biomarker classification system (i.e., the ATN model) does not fully account for health disparities and can’t explain the increased prevalence among blacks of both AD and vascular risk factors for AD such as diabetes and hypertension when compared to whites. Research on cognitive aging has traditionally focused on how decline in various cortical and hippocampal regions influences cognition. However, tau pathology emerges decades before amyloid pathology, appearing first in the brainstem; particularly in the locus coeruleus (LC), the source of brain’s norepinephrine (NE). Our decade-long studies in humans using a norepinephrine transporter (NET)- selective radiotracer ([11C]MRB) have demonstrated a special vulnerability of LC to aging and stress. Our preliminary data reveals that the decline rate of NET, normally associated with aging due to loss in NET availability and cell death, is much faster among blacks starting in the mid-30s, particularly in black males.

Objective

As the LC plays a central role in the integration and orchestration of the adaptive CNS response to various stressors or challenges, we hypothesize that cumulative exposure to socioeconomic disadvantage and racial discrimination may cause long-lasting changes in LC function followed by LC neuronal loss, which would explain the different AD phenotypical clinical presentation among blacks (i.e., less tau burden but more LC loss and vascular damage). We propose to test this hypothesis by demonstrating that there will be age and race/ethnic differences on NET availability (measured with [11C]MRB) across midlife and late-life in the LC and its target brain regions (Aim 1), and that decreased NET availability is associated with stress levels and impaired cognition (Aim 2), as well as the predictive value of NET availability on longitudinal change in cognition (Aim 3). There is the potential to determine if dysfunction of the LC is: i) a potential marker for the increased AD pathology that is observed in normal aging; ii) a key contributor to the development of metabolic syndrome, vascular dysfunction, and cognitive decline, as result of chronic stress; iii) associated with increased prevalence of both AD and vascular risk factors for AD in blacks when compared to whites; iv) associated with everyday stress levels and cumulative stress burden; v) a key mechanism that contributes to the health disparities in AD expression. This innovative study will test whether loss of LC-NE function better predicts cognitive impairment than current ATN biomarkers, particularly among blacks, suggesting a novel approach to racial-dependent strategies for diagnosis and therapeutical interventions in AD.

Contact Us

For more information about this project, please contact TSCS@miami.edu

Reducing sleep health disparities was recognized as a priority area for intervention by the National Institutes of Health. Insufficient sleep, which unfairly affects minorities, is an important preventable and treatable disease that should be targeted as it is associated with increased cardiovascular risk and disease outcomes, including obesity, diabetes, hypertension, stroke, cardiac arrhythmia, and chronic heart failure.

The purpose of our Determinants of Insufficient Sleep Among Blacks and Effects on Disparities in Health Outcomes (ESSENTIAL) study is to develop profiles of Black people who are at increased risk of insufficient sleep through your participation in a home-based study and clinical visit. With the information collected, our research team can determine the combination of psychosocial and environmental modifications that will lead to reducing insufficient sleep and related health conditions among Black people.

Who Can Participate

Black individuals who are 18 years of age or older may qualify to participate. We aim to enroll more than 500 volunteers for the 5-year duration of this study. If you are interested in participating, please complete our REDCap survey, and a member of our study team will contact you.

Contact Us

For more information and to register as a potential volunteer, please contact ESSENTIAL@miami.edu

The Haitian Wellbeing Study is a longitudinal study to investigate mental health and wellbeing among Haitians in the United States and in Haiti. The large, prospective study aims first to identify the most important mental health, overall health, and sleep-related factors through focus groups. The researchers will also look at factors including employment, education level, income, immigration status, gender, genomic factors, and type and level of traumatic event exposure.
The results will then inform a survey designed to evaluate the impact of specific stressful factors among larger numbers of Haitians and Haitian Americans. The project could also reveal differences between Haitians, Haitian immigrants to the U.S., and Haitian American U.S. citizens who may be more acclimated to the culture in this country.

The ultimate goal is to enroll 1,000 participants in the study. Depending on funding, the study could follow even more people for up to 10 years to note any changes. The hope is that focus group feedback and survey responses will lead to effective solutions to boosting the well-being of Haitian populations.

For more information on the Haitian Well-Being Study, call 305-243-7452 or e-mail Haitianstudy@miami.edu.

The Nurturing Moms Project uses virtual reality to evaluate and reduce stress among Black and Latina expectant and postpartum women. The project, conducted in partnership with the Miller School’s Media and Innovation Lab, provides headsets preloaded with VR videos to women currently pregnant and to others who gave birth in the previous 12 months. Effectiveness is measured after each VR session and following completion of the year-long study to gauge the technology’s short- and long-term impact on maternal mental health. 

The VR videos are designed as an immersive experience that is part education, part mindfulness. 

For more information on the Nurturing Moms study, email nurturevr@miami.edu or call 305-243-7931 or 786-584-8003.

Latinos and Latinas, the largest minority ethnic group in the United States, appear to be most affected by the rural–urban divide in cardiovascular disease health outcomes. They are unequally more burdened by cardiovascular risks, such as excess weight and obesity, hypertension, dyslipidemia, diabetes, and cardiovascular mortality, compared with other racial and ethnic groups. Cardiovascular mortality alone accounts for 20 percent of deaths, the second-most leading cause of death, among Latinos and Latinas.

Your voluntary participation in our Determinants of Insufficient Sleep in Rural–Urban Settings (DORMIR) study will allow our research team to provide possible factors that have contributed to these negative health outcomes. These findings can lead to actionable clinical, lifestyle, and policy interventions that can improve the health of the Latino and Latina community.

Who Can Participate

Latinos and Latinas who are 18 years of age or older may qualify to participate. We are enrolling more than 500 volunteers in this 5-year study. If you are interested in participating, please complete our REDCap survey, and a member of our study team will contact you.

Contact Us

For more information and to register as a potential volunteer, please contact DORMIR@miami.edu

The Mechanisms of Sleep Deficiency and Effects on Brain Injury and Neurocognitive Functions Among Older Blacks (MOSAIC) study will attempt to look at the interaction between Alzheimer’s disease and sleep disruption. Adults displaying sleep deficiency, defined as poor sleep, sleep apnea, and circadian misalignment, have a greater risk of Alzheimer’s disease, cognitive decline, or preclinical Alzheimer’s disease. Sleep deficiency is a key target for preventing Alzheimer’s disease. This study will investigate a number of factors ranging from social capital to brain markers and neurocognitive function.

With your voluntary participation in our home-based study, our research team will attempt to determine some of the causes leading to sleep deficiency and describe their potential role in explaining the observed disparities in markers of brain health of older Black people.

Who Can Participate

Black individuals who are 55 to 85 years of age may qualify to participate. We aim to enroll more than 500 volunteers for the 4.5-year duration of this study. If you are interested in participating, please complete our REDCap survey, and a member of our study team will contact you.

Contact Us

For more information and to register as a potential volunteer, please contact MOSAIC@miami.edu

Background

Recent evidence suggests that older African Americans (AAs) are at a higher risk of developing amyloid deposition independently of vascular disease, which would partially account for the increased prevalence of dementia among AAs. We will extend prior work in this population to test whether poor slow wave sleep (SWS), which is more common among AAs when compared to whites, is one of the factors that explains these associations.

African Americans (AAs) have an increased prevalence of Alzheimer's disease (AD) compared to whites, which traditionally has been associated to the presence of vascular disease. However, a recent community- based study of non-demented elderly, as well as our preliminary data, suggest that AAs have higher amyloid burden after adjusting for vascular risk factors, which points to the presence of additional genetic or physiological differences on AD-risk by race. The purpose of this study is to test whether poor slow wave sleep (SWS) is one of these factors. Sleep disturbances vary between AAs and non-Hispanic whites. AAs take longer to fall asleep, have shorter sleep duration, lower sleep efficiency and, more characteristically, less SWS duration when compared to whites. Relatedly, amyloid positive healthy elderly, as well as those with mild cognitive impairment (MCI) and AD, experience more sleep fragmentation and decreased SWS and REM sleep duration than their healthy counterparts. This suggests: i) that disturbed sleep contributes to AD-neurodegeneration (or that sleep is particularly sensitive to amyloid deposition); and ii) that race-related sleep differences might contribute to the reported increases in amyloid burden in AAs.

Objective

The study has two goals: first, to confirm that black race is associated in vivo with longitudinal increases in amyloid-PET uptake and cognitive decline; second, to demonstrate that poor SWS at baseline is associated with these increases after controlling for the cardiovascular morbidity that is shared between sleep disturbances and dementia and might confound these associations. In consultation with community stakeholders, we will recruit 150 cognitively normal AA elderly (ages 55-75 years) and 60 whites balanced by age, sex, BMI, education, and other socio-demographic variables and from the same Brooklyn neighborhoods. Visit one will include a full clinical evaluation, neuropsychological tests, and clinical labs. Participants will later undergo home monitoring for OSA for two nights followed by 5 days of actigraphy. Subjects with normal sleep breathing will be invited to perform 2 nights of nocturnal polysomnography (NPSG) followed by a second final visit in which amyloid load and cerebrovascular morbidity will be analyzed by 11C-PiB PET-MR. All subjects will be invited to repeat both visits after 30 months.

This study has the potential to identify clinical (and treatable) predictors of amyloid burden in cognitively normal AA elderly and would be an important step towards the prevention of dementia in the black community as well as the reduction of health inequities.

Contact Us

For more information about this project, please contact TSCS@miami.edu