Clinical trial NCT03934255: Circadian Mechanisms Underlying Non-Dipping Blood Pressure in Blacks
Official title: Central and Peripheral Circadian Mechanisms Underlying Non-Dipping Blood Pressure in Blacks
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Circadian Rhythm
Blood Pressure
Lead sponsor: University of Alabama at Birmingham
Sponsor class: OTHER
Collaborators: name: American Heart Association
First posted: 2019-05-01
Enrollment: 32
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: NA
Intervention model: SINGLE_GROUP
Intervention model description: Constant routine protocol in Blacks with dipping and non-dipping blood pressure
Primary purpose: BASIC_SCIENCE

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.

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.

Eligibility 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

Primary outcomes:
measure: Melatonin phase
timeFrame: Melatonin phase during a 30-hour constant routine protocol
measure: Melatonin amplitude
timeFrame: Melatonin amplitude during a 30-hour constant routine protocol
measure: Core body temperature phase
timeFrame: Core body temperature phase during a 30-hour constant routine protocol
measure: Core body temperature amplitude
timeFrame: Core body temperature amplitude during a 30-hour constant routine protocol
measure: Buccal cell mRNA expression
timeFrame: Expression of Bmal1 and Period 3 during a 30-hour constant routine protocol
Secondary outcomes:
measure: Cortisol phase
timeFrame: Cortisol phase during a 30-hour constant routine protocol
measure: Cortisol amplitude
timeFrame: Cortisol amplitude during a 30-hour constant routine protocol
Other outcomes:
Locations:
city: Birmingham
country: United States
facility: University of Alabama at Birmingham
state: Alabama
Study officials:
References: