Cardiovascular Risk Factor, Hypertension
Conditions
Keywords
circadian rhythm
Brief summary
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.
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.
Interventions
BEHAVIORALForced Desynchrony
Participants will complete a 7-day circadian study protocol with numerous repeated blood pressure and other cardiovascular measures across the circadian cycle. 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.
Sponsors
Oregon Health and Science University
National Heart, Lung, and Blood Institute (NHLBI)
Study design
Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
30 Years to 60 Years
Healthy volunteers
Yes
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Nighttime Systolic Blood Pressure | Baseline Night Average | Systolic blood pressure measured via automatic sphygmomanometer every 30 minutes during sleep period at baseline. Readings recorded in units of mmHg. |
| Nighttime Diastolic Blood Pressure | Baseline Night Average | Diastolic blood pressure measured via automatic sphygmomanometer every 30 minutes during sleep period at baseline. Readings recorded in units of mmHg. |
| Daytime Systolic Blood Pressure | Baseline Daytime Average | Systolic blood pressure measured via automatic sphygmomanometer every 20 minutes during the daytime period at baseline. Readings recorded in units of mmHg. |
| Daytime Diastolic Blood Pressure | Baseline Daytime Average | Diastolic blood pressure measured via automatic sphygmomanometer every 20 minutes during the daytime period at baseline. Readings recorded in units of mmHg. |
| Change in Systolic Blood Pressure Across Sleep Period | 7 days in the laboratory | Change in systolic blood pressure per hour of scheduled sleep period measured via automatic sphygmomanometer every 30 minutes across each of the scheduled sleep periods while participants stayed 7-nights and days in the laboratory. Sleep was scheduled to occur at varied times across the entire circadian cycle so that the effects of the circadian cycle can be ignored (i.e., averaged out). |
| Change in Diastolic Blood Pressure Across Sleep Period | 7 days in the laboratory | Change in diastolic blood pressure per hour of scheduled sleep period measured via automatic sphygmomanometer every 30 minutes across each of the scheduled sleep periods while participants stayed 7-nights and days in the laboratory. Sleep was scheduled to occur at varied times across the entire circadian cycle so that the effects of the circadian cycle can be ignored (i.e., averaged out). |
| Circadian Amplitude of Systolic Blood Pressure When Awake | 7 days in the laboratory | Systolic blood pressure was assessed manually via sphygmomanometry during each scheduled wakefulness period while participants stayed 7-nights and days in the laboratory. Behaviors during wakefulness were standardized and scheduled to occur across the entire circadian cycle. Any systematic circadian rhythmicity was assessed by analysis of variance which revealed the underlying amplitude of the circadian rhythm of systolic blood pressure while controlling for (averaging out) any ongoing behaviors. |
| Circadian Amplitude of Diastolic Blood Pressure When Awake | 7 days in the laboratory | Diastolic blood pressure was assessed manually via sphygmomanometry during each scheduled wakefulness period while participants stayed 7-nights and days in the laboratory. Behaviors during wakefulness were standardized and scheduled to occur across the entire circadian cycle. Any systematic circadian rhythmicity was assessed by analysis of variance which revealed the underlying amplitude of the circadian rhythm of diastolic blood pressure while controlling for (averaging out) any ongoing behaviors. |
Countries
United States
Contacts
PRINCIPAL_INVESTIGATORSteven A Shea, PhD
Ore
Participant flow
Recruitment details
Participants were recruited from the general population using established methods via flyers across the OHSU campus, community bulletin boards, internet advertisements (ResearchMatch.com, OCTRI's research Data Warehouse, clinicaltrials.gov, Craigslist, Facebook-using lab or The Oregon Institute of Occupational Health Sciences accounts), and booths at community health fairs (see protocol for additional details).
Pre-assignment details
Nothing to report
Baseline characteristics
| Characteristic | — |
|---|---|
| Age, Continuous | 43.3 Years STANDARD_DEVIATION 9.7 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 0 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 5 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants |
| Race (NIH/OMB) Black or African American | 0 Participants |
| Race (NIH/OMB) More than one race | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants |
| Race (NIH/OMB) White | 19 Participants |
| Sex: Female, Male Female | 11 Participants |
| Sex: Female, Male Male | 3 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 25 | 0 / 5 |
| other Total, other adverse events | 8 / 25 | 4 / 5 |
| serious Total, serious adverse events | 0 / 25 | 0 / 5 |
Outcome results
None listed