Reducing African Americans' Alzheimer's Disease Risk Through Exercise (RAATE)" (RAATE)

The RAATE proposal is designed to determine the effects of physical activity on risk factors for Alzheimer's Disease in older African American adults. The study will compare a physical activity program to an active control group. There are three main objectives of the protocol: 1) to determine if a physical activity intervention tailored to older African American adults is effective in modifying cognitive function associated with Alzheimer's Disease, 2) to determine if a physical activity intervention tailored to older African American adults is effective in modifying brain function and structure associated with Alzheimer's Disease, and 3) to determine if a physical activity promotion intervention tailored to African American adults is effective at enhancing physiological parameters. The primary endpoints for the study are episodic memory and executive functioning. The secondary outcomes include anthropometry, blood pressure, brain activation, cerebral blood flow, volume of whole brain and white matter hyperintensities, cardiorespiratory fitness, objectively measured physical activity, circulating hormones, and telomere length.

Alzheimer's disease is steadily increasing in prevalence, with a devastating public health impact. The prevalence of Alzheimer's Disease is higher in African Americans compared to white Americans, thereby constituting a health disparity. Interventions that prevent Alzheimer's disease or change the course of cognitive decline associated with Alzheimer's disease are needed. Most older adults do not achieve recommended levels of physical activity, and this includes African Americans. Regular physical activity has proven to be a safe and effective means to enhance cognitive function in older adults ranging from cognitively healthy to mildly cognitively impaired. Therefore, our study is focused on physical activity promotion, a potent approach to modifying multiple neurobiological pathways implicated in Alzheimer's Disease. We evaluate exercise benefits among elderly African Americans, who are understudied and in whom the natural course of neurodegeneration, exercise effects on neuroprotection and neurodegeneration, and resulting clinical phenotypes may differ. A large body of existing data suggests that exercise improves cardiovascular and cerebrovascular functioning, and thus has the potential to enhance perivascular clearance of amyloid and reduce chronic brain tissue ischemia, among other beneficial effects. At the same time, chronic exercise has been shown to decrease central levels of inflammatory markers and increase central levels of neurotrophic factors, which in turn promote protection against Alzheimer's Disease neurodegeneration pathways via a variety of mechanisms. While physical activity interventions have been shown to have positive effects on these factors and on resultant cognitive functioning in older adults, nearly all interventions have had a negligible representation of African Americans. Prior data suggests that African Americans enter their elderly years against a backdrop of different lifespan exposures to a variety of factors relevant to neuroprotection and neurodegeneration, including cardiovascular risk, exercise, diet, and education. In addition, prior data suggests that the key genetic risk factor for Alzheimer's Disease (APOE) may have differing consequences for Alzheimer's Disease risk among African Americans, and other genetic differences have the potential to influence the brain benefits of physical activity in this community. We will utilize a randomized clinical trial to addresses these questions. Participants will be randomized into a physical activity promotion intervention or a healthy aging information group for 52 weeks. All participants will be of normal cognitive function. We will assess cognitive function, brain structure and function, circulating hormones, objectively measured physical activity, cardiorespiratory fitness, and telomere length. Our study will take the first step toward understanding whether the hypothesized benefits of exercise for the brain carry over to elderly African Americans.

The intervention group will target 150 minutes of moderate to vigorous aerobic physical activity and two days of strength training, consistent with the current physical activity recommendations. Participants will engage in 2 days per week of supervised activity at community facilities. These participants will be requested to engage in an additional 30 minutes of moderate to vigorous aerobic physical activity two days per week at home.

The active control group will be based on a low-intensity activity program and a healthy aging educational component. The physical activities will include stretching, balance training, flexibility, relaxation, and practicing activities of daily living. The successful aging education component will cover topics including avoiding scams, fall prevention, living wills, and dementia awareness.

Seminars of health topics related to aging in African Americans with light stretching and low intensity activites

The Rey Auditory Verbal Learning Test (RAVLT) is a common neuropsychological tool used to evaluate episodic memory. The RAVLT involves providing participants with 15 unrelated words and asking them to recall the word list. There are 5 trials designed to determine short-term memory and then a 30 minute delay to assess long-term memory. The total words correct in both the short- and long-term trials are used as outcome measures.

The NIH Toolbox Executive Function subdomain consists of the Flanker Inhibitory Control and Attention Test and the Dimensional Change Card Sort Test. The Flanker test is a measure of one's ability to inhibit attention to irrelevant conditions. Participants must identify the direction of a central visual stimuli amongst flanking stimuli either congruent or incongruent with the central stimuli. There are 40 trials and scores range from 0 - 10. The Card Sort is a measure of the ability to shift attention based on rules. Participants must match a target visual stimuli to either a color or word stimuli and this matching shifts during the assessment.

The Actigraph WGT3X+ accelerometer (ActiGraph LLC, Pensacola, FL) will be worn by the participant for a 7-day period. The device provides both the number of steps per day as well as time in sedentary, light, moderate, and vigorous activity in 1-minute epochs (for adults) using the default filter.

All participants will perform a standardized graded exercise testing protocol administered on a treadmill. Fitness will be measured in terms of mL oxygen/kg/min.

Physical function will be assessed using the NIH-TB Motor assessment, which assesses dexterity, balance, locomotion, grip strength, and strength.

DNA will be extracted from the blood draw and amplified using real-time quantitative polymerase chain reaction (qPCR) to determine average relative telomere length represented by the telomere repeat copy number to single gene copy number (T/S) ratio in triplicate as previously described

Volumes of the cranial vault, brain tissue, gray matter, white matter, and cerebrospinal fluid, which will be provided as the primary brain structural outcome measures of interest from MRI.

Pre-selected inhibitory control ROIs (ACC for the Stroop; DLPFC, thalamus, superior frontal, inferior frontal, fusiform, and middle frontal gyri; and ACC and middle frontal gyri for the ANT) are of primary interest.

Physical function will be assessed using the the Short Physical Performance Battery (SPPB), which is a brief performance battery based on timed short distance walk, repeated chair stands and balance test.

Inclusion Criteria: self- identify as African American 60 years and older willing to accept randomization willing to attend group sessions lacking plans to move during the study period free of conditions that would make regular exercise unsafe (e.g. uncontrolled asthma, severe sickle cell disease, etc.) not engaged in regular physical activity Short Physical Performance Battery score >/= 4 physically capable of exercise, Exclusion Criteria: cognitive impairment that would interfere with participating in group interactions unwilling to give written informed consent inability to attend group sessions conditions that prevent regular exercise conditions that the medical or principal investigator determine to warrant exclusion

For all study data, Pennington Biomedical has a well-structured internal process for data sharing and transfer. The Office of Legal and Regulatory Compliance is responsible for all data agreements which includes data subject to the protection under HIPAA. As part of the Louisiana State University System, Pennington Biomedical ensures that data agreements are in place in the following circumstances: business associate agreements when the transfer of data contains all identifiers, data use agreements when the transfer of data contains those identifiers that constitute a limited data set and a data transfer agreement in instances where data is de-identified, but still may be subject of protection in order to protect intellectual property rights. Transmission of data to ensure proper safeguards are in place on the data in motion and data at reset are carried out with assistance of the Research Computing Group or the Office of Computing Services.