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Circadian Mechanisms Underlying Non-Dipping Blood Pressure in Blacks

  • Clinicaltrials.gov identifier

    NCT03934255

  • Recruitment Status

    Recruiting

  • First Posted

    May 1, 2019

  • Last update posted

    April 28, 2020

Study Description

Brief summary:

This study seeks to examine central and peripheral circadian mechanisms in Blacks with appropriately dipping systolic blood pressure (blood pressure that dips by at least 10%) compared with non-dipping systolic blood pressure (blood pressure that dips by less than 10%) using a constant routine protocol. Constant routine protocols are commonly used in the field of circadian biology to examine rhythms in biological processes while controlling the entraining effects of light, activity, and diet.

  • Condition or Disease:Blood Pressure
    Circadian Rhythm
  • Intervention/Treatment: Other: Constant Routine Protocol
  • Phase: N/A

Detailed Description

This study will enroll a total of 40 participants (n=20 non-dippers; n=20 dippers) to complete a 30-hour constant routine protocol. Participants will undergo baseline testing that includes anthropometric measurements, clinic blood pressure measurements, completion of self-report questionnaires on sleep and mood, be fitted with an ambulatory blood pressure monitor and actigraphy watch, and be provided with home sleep testing (HST) equipment. Following completion of baseline assessment, eligible participants will be scheduled for the 30-hour constant routine protocol. The 30-hour constant routine protocol will allow for the hourly collection of saliva, collection of buccal cells every 4 hours, and constant monitoring of core body temperature, all of which are primary outcomes in the assessment of central and peripheral circadian clock markers. Amplitude and phase of these outcomes will be assessed in non-dippers versus dippers.

Study Design

  • Study Type: Interventional
  • Estimated Enrollment: 40 participants
  • Intervention Model: Single Group Assignment
  • Intervention Model Description: Constant routine protocol in Blacks with dipping and non-dipping blood pressure
  • Masking: None (Open Label) ()
  • Primary Purpose: Basic Science
  • Official Title: Central and Peripheral Circadian Mechanisms Underlying Non-Dipping Blood Pressure in Blacks
  • Actual Study Start Date: January 2020
  • Estimated Primary Completion Date: March 2022
  • Estimated Study Completion Date: March 2022

Arms and interventions

Arm Intervention/treatment
Experimental: Constant Routine Protocol
Participants will be kept in constant conditions for 30 hours to observe circadian physiology in the absence of light, physical activity, and meals.
Other: Constant Routine Protocol
Constant routine protocols are used in circadian research to examine underlying circadian rhythms in the absence of light, activity, and meals

Outcome Measures

  • Primary Outcome Measures: 1. Melatonin phase [ Time Frame: Melatonin phase during a 30-hour constant routine protocol ]
    Circadian phase of melatonin obtained from saliva
  • 2. Melatonin amplitude [ Time Frame: Melatonin amplitude during a 30-hour constant routine protocol ]
    Circadian amplitude of melatonin obtained from saliva
  • 3. Core body temperature phase [ Time Frame: Core body temperature phase during a 30-hour constant routine protocol ]
    Circadian phase of core body temperature recorded and transmitted wirelessly
  • 4. Core body temperature amplitude [ Time Frame: Core body temperature amplitude during a 30-hour constant routine protocol ]
    Circadian amplitude of core body temperature recorded and transmitted wirelessly
  • 5. Buccal cell mRNA expression [ Time Frame: Expression of Bmal1 and Period 3 during a 30-hour constant routine protocol ]
    Expression of Bmal1 and Period 3 obtained from buccal cell mRNA
  • Secondary Outcome Measures: 1. Cortisol amplitude [ Time Frame: Cortisol amplitude during a 30-hour constant routine protocol ]
    Circadian amplitude of cortisol obtained rom saliva
  • 2. Cortisol phase [ Time Frame: Cortisol phase during a 30-hour constant routine protocol ]
    Circadian phase of cortisol obtained rom saliva

Eligibility Criteria

  • Ages Eligible for Study: 18 Years and older (Adult, Older Adult)
  • Sexes Eligible for Study: All
  • Accepts Healthy Volunteers: Yes

Criteria

Inclusion Criteria:

- Black or African American race

- Age 18 years or older

Exclusion Criteria:

- Work alternating or night shifts

- Pregnant or nursing

- Current illicit drug use

- History of severe mental illness

- Medical conditions that would be contraindicated for a constant routine protocol

- Take anti-hypertensive medications or beta-blockers

- Severe obstructive sleep apnea

Contacts and Locations

Contacts

Contact: Stephen J Thomas, PhD 205-934-3367 sjthoma@uabmc.edu

Locations

United States, Alabama
University of Alabama at Birmingham
Birmingham

Sponsors and Collaborators

University of Alabama at Birmingham

American Heart Association

More Information

  • Responsible Party: University of Alabama at Birmingham
  • ClinicalTrials.gov Identifier: NCT03934255 History of Changes
  • Other Study ID Numbers: IRB-300003266
  • First Posted: May 1, 2019 Key Record Dates
  • Last Update Posted: April 28, 2020
  • Last Verified: April 2020
  • Individual Participant
    Data (IPD) Sharing
    Statement:

  • Plan to Share IPD: Undecided
  • Plan Description: Details regarding sharing IPD are undecided. Protocols and consent forms will be shared. Requests may be made to the study PI.
  • Studies a U.S. FDA-regulated Drug Product: No
  • Studies a U.S. FDA-regulated Device Product: No