Aerobic Exercise for Older Adults at Increased Risk of Alzheimer's Disease and Related Dementias (BIMII)
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|ClinicalTrials.gov Identifier: NCT03035851|
Recruitment Status : Recruiting
First Posted : January 30, 2017
Last Update Posted : September 26, 2019
The estimated annual cost of dementia in Canada is $15 billion, with a projected cumulative economic burden of $800 billion by 2038. Effective prevention of dementia at a population level will need to include lifestyle factors such as promoting higher levels of physical activity. Physical inactivity is a modifiable risk factor for Alzheimer disease (AD) and cognitive decline, but the mechanisms by which physical activity exerts its protective effect on the brain remain unknown. Motivated by the need to develop strategies to prevent and treat AD and related dementias (ADRD), the investigators' overall research goal is to discover why the aging brain develops ADRD. To achieve this goal the investigators adopt a translational physiology approach (i.e., study of physiology from molecule/cell to population) to investigate how exercise improves cognitive performance, and the underlying mechanisms by which exercise prevents and/or slows down age-related declines in brain health and cognition. This approach allows the investigators to determine how physiological function is related to ADRD, with important implications for health. The investigators' prior work demonstrated a significant relationship between fitness, vascular regulation and cognition in older adults free of overt disease. These findings have implications for vascular cognitive impairment and ADRD, in which hypoperfusion and dysregulation of cerebral blood flow are thought to be important pathophysiological factors. The investigators' central hypothesis is that regular aerobic exercise mitigates age-related decreases in vascular function and cerebrovascular reserve, which in turn benefits cognition. Work by the investigators and others has provided the necessary data justifying a randomized controlled trial to evaluate the role of exercise in the prevention of ADRD.
The investigators are well equipped to undertake this trial; the investigators have dedicated institutional support and necessary expertise in vascular regulation, cognition, aging, neuroimaging and genetics.
The overall objective of this proposal is to test an exercise intervention for secondary prevention of ADRD in adults between 50 and 80 years old who are at increased risk for ADRD (with memory impairment symptoms but without dementia). The rationale for this trial is the urgent need for dementia prevention: an exercise intervention, which harnesses a translational physiology framework, holds such promise. The investigators will conduct this trial to determine the effects of aerobic exercise on the development of age-associated cognitive decline and dementia. The exercise intervention is designed with input from Alberta Health Services, the universal healthcare provider for Albertans, so that the intervention can be readily adopted into clinical practice if this trial is successful. The trial will address three specific aims.
SPECIFIC AIM 1: Determine the independent effect of exercise on cognitive performance in previously inactive older adults at increased risk of ADRD. The investigators hypothesize that participants randomized to our six-month aerobic exercise intervention will perform better on cognitive tests, compared to control participants randomized to a stretching-toning exercise group.
SPECIFIC AIM 2: Determine underlying biological mechanisms that influence cognitive performance after exercise training. The investigators hypothesize that exercise improves cognition due to changes at molecular/cellular (biomarkers), vascular (cerebral blood flow, cerebrovascular reserve), anatomical and functional (neuroimaging), and behavioural (sleep quality) levels. Further, the investigators hypothesize that ADRD-specific genetic risk scores, reflective of targeted genetic variants, moderate exercise-related cognitive and brain outcomes.
SPECIFIC AIM 3: Determine the extent to which changes in cognition, resting cerebral blood flow and cerebrovascular reserve persist 12 months after participants complete a 6-month exercise training intervention. The investigators hypothesize that the effects of improved aerobic fitness will be maintained over time as a function of persistent lifestyle changes and behavioural support programs. This trial will provide evidence needed to make clinical recommendations for exercise programs in adults at risk for ADRD, with the goal of preventing dementia. Given the investigators' extensive stakeholder input, this intervention will be easily translated to other jurisdictions. This research into the mechanisms of effect for exercise will identify patient subgroups most likely to benefit, surrogate outcome markers for use in future trials to refine intervention dose/duration, and new therapeutic targets for future interventions.
|Condition or disease||Intervention/treatment||Phase|
|Alzheimer Disease Dementia||Behavioral: Aerobic exercise Behavioral: Stretch and Strength||Not Applicable|
|Study Type :||Interventional (Clinical Trial)|
|Estimated Enrollment :||264 participants|
|Intervention Model:||Parallel Assignment|
|Masking:||Single (Outcomes Assessor)|
|Official Title:||Aerobic Exercise for Older Adults at Increased Risk of Alzheimer's Disease and Related Dementias: Harnessing Translational Physiology|
|Study Start Date :||January 2017|
|Estimated Primary Completion Date :||June 2024|
|Estimated Study Completion Date :||January 2025|
Experimental: Aerobic exercise
Participants will take part in a supervised 6-month-long aerobic (walk/jog) training program held 3 days/week. Each session will include a 5-min warm-up, 20-40 min of aerobic exercise (walking, jogging), 5-min cool-down, and stretching. Exercise prescriptions will follow current principles and guidelines established by ACSM/AHA, including sufficient warm-up, cool-down, and ongoing provision of safety precautions/exercise tips. As participants progress, the duration of aerobic exercise will increase from 20 (month 1) to 30 (months 2-3) and 40 min (months 4-6), with proportional increases to warm-up and cool-down periods. Exercise intensity will be based on individual maximal oxygen uptake (VO2 max), measured at baseline. Intensity will build from 30-45% (months 1-3) to mitigate the risk of injury and will progress to 60-70% (months 4-6) heart rate reserve (HRR).
Behavioral: Aerobic exercise
Stretch and Strength
A control group will meet on a similar schedule as the exercise group for sessions on stretching and toning but without aerobic exercise. Based on prior RCTs of similar interventions the investigators expect this control to be ineffective or minimally effective, but anticipate that it will increase participant enthusiasm and retention. All assessments will be conducted in this arm.
Behavioral: Stretch and Strength
- Change in Cognition Assessed by Neuropsychological Test Battery [ Time Frame: Measured at baseline, exercise intervention completion (6 months) and follow-up (18 months) ]
- Change in Cerebral Blood Flow Assessed by Transcranial Doppler Ultrasound [ Time Frame: Participants will be assessed at baseline, at the completion of the intervention (6 months) and at follow-up (18 months) phases of the study. ]
- Change in Maximal Oxygen Uptake (VO2max) Assessed by Metabolic Cart [ Time Frame: Participants will be assessed at baseline, at the completion of the intervention (6 months) and at follow-up (18 months) phases of the study. ]The change in aerobic fitness will be assessed by VO2max, determined by cardiopulmonary stress testing.
- Change in Blood Biomarkers Assessed by Elisa Assays [ Time Frame: Participants will be assessed at baseline, at the completion of the intervention (6 months) and at follow-up (18 months) phases of the study. ]blood sampling and analyses of the selected markers (e.g., neurotrophins, cytokines, inflammatory markers, cortisol, oxidative stress, NO and antioxidants).
- Change in Risk/protective factors Assessed by Questionnaires [ Time Frame: Participants will be assessed at baseline, at the completion of the intervention (6 months) and at follow-up (18 months) phases of the study. ]Measures include changes in dietary intake, food frequency, supplement intake, physical activity, cognitive activities, mood changes, social support and engagement.
- Change in Brain Structure and Function Assessed by Neuroimaging Modalities [ Time Frame: Participants will be assessed at baseline, at the completion of the intervention (6 months) and at follow-up (18 months) phases of the study. ]
- Change in Sleep Quality Assessed by Polysomnography, Actigraphy and Questionnaires [ Time Frame: Participants will be assessed at baseline, at the completion of the intervention (6 months) and at follow-up (18 months) phases of the study. ]
- Change in Health behaviour with appropriate support strategies [ Time Frame: Participants will be assessed at 6, 12 and 18 months. ]The investigators will assess whether, in the 12-month period following the 6-month exercise intervention, individually-tailored, telephone support for home-based exercise improves adherence and sustains the beneficial effects of exercise.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03035851
|Contact: Marc J Poulin, PhD, DPhilemail@example.com|
|University of Calgary||Recruiting|
|Calgary, Alberta, Canada|
|Contact: Marc J Poulin|
|Principal Investigator:||Marc J Poulin, PhD, DPhil||University of Calgary|