The purpose of the study is to find out the effects of neighborhood disadvantage and sleep disparities contribute to racial disparities in cardiometabolic health and blood pressure in young adults.
There are well-documented disparities between Black and white Americans in the incidence of cardiovascular disease, the leading cause of death in America. There are also disparities between Black and White Americans in the incidence of hypertension (high blood pressure; BP), which is the leading risk factor for cardiovascular disease. Our long-term goal is to determine effective strategies to prevent racial disparities in cardiovascular health. In this proposal, the investigators will focus on determining societal and biological mediators of racial disparities in young adults that can be targeted in future interventions. Poor sleep is associated with adverse cardiovascular events and hypertension. Moreover, recent meta-analyses demonstrate that Black adults have consistently poorer sleep health than White adults, including receiving fewer total sleep minutes and having worse overall sleep quality. Neighborhood socioeconomic environments influence health behaviors through both material resources (e.g., access to healthful foods and safe public space) and social norms (e.g. exercise, diet, smoking). A well-documented history of discriminatory policies and practices has resulted in black individuals living in more disadvantaged physical and social environments than whites. As such, they experience greater adverse exposures (e.g., racism, violence and stress), which negatively impact sleep, resulting in dysregulation of cardiometabolic health. Therefore, the investigators seek to determine the role of neighborhood disadvantage and sleep in contributing to racial disparities in cardiovascular health.
Study Type
OBSERVATIONAL
Enrollment
55
Kinesiology Building
Auburn, Alabama, United States
Flow-mediated dilation (FMD)
Flow-mediated vasodilation will be assessed using continuous measures of brachial artery diameter and velocity via duplex Doppler ultrasound (Hitachi Arietta 70). The brachial artery will be imaged in the longitudinal plane proximal to the medial epicondyle using a high-frequency (6-12 MHz) linear-array probe. The ultrasound probe will be stabilized using a custom-built clamp. Shear rate (sec-1) will be calculated as \[(blood flow velocity (cm\*s-1) \*4)/blood vessel diameter (mm)\] The image will be recorded throughout a 60-s baseline, a 300-s ischemic stimulus (250 mmHg), and 180 seconds post deflation. FMD will be expressed as % dilation (final diameter-baseline diameter/baseline diameter x 100) and also normalized to the shear stimulus. Allometric scaling will be used if appropriate, including if there are baseline differences in artery diameter by race or condition.
Time frame: Baseline racial comparison
Pulse wave velocity (arterial stiffness)
The investigators will use the SphygmoCor XCEL system to assess pulse wave velocity (PWV). A high-fidelity strain-gauge transducer is used to obtain the pressure waveform at the carotid pulse. Distances from the carotid artery sampling site to the femoral artery (upper leg instrumented with a thigh cuff for oscillometric sphygmomanometry), and from the carotid artery to the suprasternal notch will be recorded.PWV will be expressed as cm/s.
Time frame: Baseline racial comparison
Pulse wave analysis (arterial stiffness)
The investigators will use the SphygmoCor XCEL system to assess pulse wave analysis (PWA) using an upper arm blood pressure cuff. PWA will be expressed as % (calculated as augmentation pressure divided by the pulse pressure).
Time frame: Baseline racial comparison
24-hour ambulatory blood pressure
Participants will wear an Oscar2 (with SphygmoCor) ambulatory blood pressure monitor on their upper arm for up to 24-hours preceding their study visit to measure systolic and diastolic blood pressure. The purpose of the ambulatory blood pressure monitoring is to determine blood pressure regulation over an entire day. This blood pressure monitor will be set to automatically take blood pressure every 20 minutes. The monitor records and saves each blood pressure measurement automatically.
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Time frame: Baseline racial comparison
Blood pressure reactivity
The investigators will measure systolic and diastolic pressure using photoplethysmography at the finger. Systolic and diastolic blood pressure will be assessed at rest and during handgrip exercise. Blood pressure reactivity will be expressed as a change in pressure (mmHg) from baseline to a predetermined time during the stressor (e.g., minute one average and minute two average).
Time frame: Baseline racial comparison
Objective sleep duration and quality
Philips actiwatch spectrum will be used to quantify sleep duration. Participants will wear the watch units for 7 days. The investigators will cross-check actigraphy wear times with a sleep diary.
Time frame: Baseline racial comparison
Subjective sleep quality
The investigators will use the Pittsburgh Sleep Quality Index (PSQI) to asses sleep duration and perceived sleep quality reflective of the one month period leading into the study. The PSQI global score has a possible range of 0-21 points.
Time frame: Baseline racial comparison
Circulating reactive oxygen species
The investigators will use electron paramagnetic resonance to measure reactive oxygen species (spectra units) in whole blood samples treated with a spin probe.
Time frame: Baseline racial comparison
Blood biomarkers of nitric oxide bioavailability
The investigators will measure nitric oxide metabolites (nitrate and nitrite nanomolar concentration) using chemiluminescence
Time frame: Baseline racial comparison
Physical activity
Participants will wear an ActiGraph GT3X accelerometer for seven days to objectively quantify steps per day and metabolic equivalents per day.
Time frame: Baseline racial comparison
Mental health - social anxiety
The investigators will administer the Liebowitz Social Anxiety Scale. The scale starts at 0 (none) and ends at 3 (severe) for 24 questions related to anxiety and avoidance, and a cumulative score is calculated.
Time frame: Baseline racial comparison
Mental health - depression
The investigators will administer the Beck's Depression Inventory. The scale starts at 0 and ends at 3 for 21 questions related to depression.
Time frame: Baseline racial comparison
Neighborhood disadvantage
The investigators will ask participants to identify their home addresses with investigator assistance and Google maps and potential assistance from their guardians or parents during early- and mid-childhood and adolescence. The investigators will use the participant's address and census tract information to determine measures of neighborhood quality such as median income, crime rates, and median education level.
Time frame: Baseline racial comparison
Habitual dietary intake
The investigators will instruct participants to complete a diet log for 5 days which will be operationalized with Nutrition Data System for Research (NDSR).
Time frame: Baseline racial comparison