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Completed

NCT Number: NCT03934255

Circadian Mechanisms Underlying Non-Dipping Blood Pressure in Blacks

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.

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Key information

Conditions

Circadian Rhythm Blood Pressure

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Alabama at Birmingham

Birmingham, Alabama, 35294-0017, United States

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Constant Routine Protocol

Other

Constant routine protocols are used in circadian research to examine underlying circadian rhythms in the absence of light, activity, and meals

Primary outcomes

  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 outcomes

  1. Cortisol phase

    Time frame: Cortisol phase during a 30-hour constant routine protocol

    Circadian phase of cortisol obtained rom saliva

  2. Cortisol amplitude

    Time frame: Cortisol amplitude during a 30-hour constant routine protocol

    Circadian amplitude of cortisol obtained rom saliva

Sponsors and collaborators

Lead sponsor

University of Alabama at Birmingham

Other

Collaborators

  • American Heart Association

Registry information

Official study title

Central and Peripheral Circadian Mechanisms Underlying Non-Dipping Blood Pressure in Blacks

Important dates

Study start
2020
Primary completion
2023
Study completion
2023
First posted
May 1, 2019
Registry last updated
Jun 8, 2023

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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