Health Disparities in Prevalence of Hypertension Between Black and White Americans

Sleep and Circadian Mechanisms Contributing to Disparity in Prevalence of Hypertension Between Black and White Americans

This study will be the first to distinguish the relative contributions of sleep, circadian and behavioral mechanisms to the non-dipping BP profile in Black adults and will lay the groundwork for optimizing therapies dependent on mechanisms, such as targeting sleep, targeting circadian rhythmicity, or targeting behaviors, and raising the possibility that ideal therapy for hypertension (HTN) may differ by race. This research will ultimately help to improve health and survival in black populations with HTN.

Study Overview

• Status: Recruiting
• Conditions: Hypertension; Cardiovascular Risk Factor
• Intervention / Treatment: Behavioral: Forced Desynchrony

Detailed Description

By studying standardized behaviors and regulators of BP during sleep and behavioral stresses across all circadian phases, this protocol will allow us specifically to:

1. To determine if poor sleep, while controlling for circadian phase, contributes to the higher overall BP and reduced nocturnal drop in BP in Blacks compared to Whites.
2. To determine if reduced BP responses to standardized behavioral changes across the day and night contribute to the higher overall BP and reduced nocturnal drop in BP in Blacks compared to Whites.
3. To determine if reduced circadian amplitude of BP contributes to the higher overall BP and reduced nocturnal drop in BP in Blacks compared to Whites.

• Study Type: Interventional
• Enrollment (Estimated): 52
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Nicole P Bowles, PhD; Phone Number: 5034942541; Email: bowlesn@ohsu.edu
• Study Contact Backup: Name: Latroy Robinson, BS; Phone Number: 5033463808; Email: robinlat@ohsu.edu

Study Locations

• United States
  • Oregon
    • Portland, Oregon, United States, 97239
      • Recruiting
      • Oregon Health & Science University
      • Contact: Nicole P Bowles, PhD; Phone Number: 503-494-2541; Email: bowlesn@ohsu.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 40 years to 60 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Self-identified Black or White
• 'normotensive' (resting systolic blood pressure (SBP) <140/90 mmHg) or uncomplicated stage 1 'hypertensive' (systolic BP between 140 and 160 mmHg or a diastolic (DBP) between 90 and 100 mmHg).
• free of all prescription and non-prescription drugs (including caffeine, nicotine, alcohol and herbal medications)

Exclusion Criteria:

• Currently treated with pharmacologic agents for hypertension
• Blood pressure >160/100 mmHg
• Smoked within the last year
• Regular night work or rotating shift work for the three months prior to the study
• Travel across more than three time zones during the three months prior to the study.
• Any acute, chronic or debilitating medical conditions, other than mild hypertension (140<SBP<160 or 90<DBP<100 mmHg) and severe renal disease (glomerular filtration rate <30)
• Moderate to severe obstructive sleep apnea (OSA)
• History of severe psychiatric illnesses or psychiatric disorders will be excluded, including alcoholism, drug dependency, major depression, manic depressive illness, schizophrenic disorders, panic disorder, generalized anxiety disorder, post-traumatic stress disorder, agoraphobia, claustrophobia, paranoid personality disorder, schizoid personality disorder, schizotypal personality disorder, borderline personality disorder, and antisocial personality disorder.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Forced Desynchrony; All participants will undergo a forced desynchrony protocol.	Behavioral: Forced Desynchrony; All sleep opportunities and other activities will be scheduled by the experimenter so that by the end of the study these activities are spread evenly across all phases of the internal body clock.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Blood pressure	Blood pressure will be measured via automatic and manual-operated sphygmomanometer. Readings will be recorded in units of mmHg.	7-day lab stay
Heart rate variability	Two channel ECG will be recorded for heart rate variability analysis.	7-day lab stay

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
venous epinephrine	Venous epinephrine will be measured for adrenal cortex contribution to sympathetic activity.	7-day lab stay
venous norepinephrine	venous norepinephrine will be measured for sympathetic nerve activity's contribution to sympathetic activity.	7-day lab stay
saliva cortisol	Saliva cortisol will be measured as a sympathetic potentiating hormone.	7-day lab stay
saliva melatonin	saliva melatonin will be measured as a sympathetic attenuating hormone.	7-day lab stay
venous aldosterone	venous aldosterone will be measured as an end point of renin-angiotensin and sympathetic nerve activation	7-day lab stay
venous endocannabinoids	venous endocannabinoids will be measured to estimate stress habituation.	7-day lab stay
flow mediated dilation	Flow mediated dilation will be measured as an indication of endothelial function.	7-day lab stay
beat-by-beat blood pressure	Beat-by-beat Blood Pressure will be measured in the fingers using a non-invasive blood pressure monitoring device.	7-day lab stay
24-hr ambulatory blood pressure	Ambulatory blood pressure will be measured with an automatic 24-hr blood pressure monitoring device to estimate of blood pressure dipping status.	2 day ambulatory period

Collaborators and Investigators

• Sponsor: Oregon Health and Science University
• Investigators: Principal Investigator: Steven A Shea, PhD, Ore

Study record dates

Study Major Dates

• Study Start (Actual): December 1, 2018
• Primary Completion (Estimated): July 1, 2024
• Study Completion (Estimated): July 1, 2025

Study Registration Dates

• First Submitted: June 5, 2018
• First Submitted That Met QC Criteria: June 5, 2018
• First Posted (Actual): June 15, 2018

Study Record Updates

• Last Update Posted (Actual): August 2, 2023
• Last Update Submitted That Met QC Criteria: July 31, 2023
• Last Verified: July 1, 2023

More Information

Terms related to this study

• Keywords: circadian rhythm
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Hypertension
• Other Study ID Numbers: IRB 16803

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No