Night Shift Work, On-shift Napping, and Endothelial Function: A Pilot Study

Cardiovascular disease (CVD) and CVD risk factors such as high blood pressure (BP) are disproportionately higher among night shift workers, including those who work in public safety and healthcare. The purpose of this pilot study is to assess feasibility of collecting data germane to key indicators of cardiovascular health (i.e., ambulatory blood pressure) repeatedly during a simulated night shift protocol. The primary outcome measure will be the number of participants for which at least 70% of required ambulatory BP measures were collected. A result of at least 10 participants/subjects will be considered feasible.

Study Overview

• Status: Completed
• Conditions: Blood Pressure; Endothelial Dysfunction
• Intervention / Treatment: Behavioral: Brief on-shift nap

Detailed Description

Cardiovascular disease (CVD) and CVD risk factors such as high blood pressure (BP) are disproportionately higher among night shift workers, including those who work in public safety and healthcare. Risk of CVD events such as myocardial infarction and stroke are higher among shift workers than non-shift workers. Risk of atrial fibrillation is 1.22 times greater (95%CI 1.02, 1.45) among individuals that work 3-to-8 night shifts per month versus non-shift workers. A comprehensive explanation for why shift workers, especially night shift workers, are at greater risk of CVD is not yet available. However, some research suggests that night shift workers experience repeated exposure to sleep deprivation, which impacts normal patterns in BP and endothelial function. Endothelial dysfunction and disruption of normal BP patterns are independently linked to numerous indicators of CVD, including cardiac-related mortality.

The purpose of this pilot study is to assess feasibility of collecting data germane to key indicators of cardiovascular health (i.e., ambulatory blood pressure) repeatedly during a simulated night shift protocol. Investigators propose a laboratory-based pilot study whereby participants (volunteers) complete two conditions. Condition one will include a 12-hour simulated night shift in our lab with no napping. Condition two will involve a 12-hour simulated night shift in our lab with a 45 minute nap at 0200 hours. Participants will be asked to wear monitoring devices for approximately 48 total hours with the last 12 hours of monitoring (from 1900 to 0700) to be in our lab.

Aim 1: Assess the feasibility of collecting ambulatory BP measures (ABPM) and indicators of endothelial function at multiple time points prior to, during, and after simulated night shift work.

The primary outcome measure will be the number of participants for which at least 70% of required ambulatory BP measures were collected. A result of at least 10 participants/subjects will be considered feasible.

Aim 2: Characterize the impact of simulated night shift work and on-shift napping on BP dipping and endothelial function.

Secondary endpoints include quantifying descriptive statistics (e.g., means and standard deviations) for BP dipping and endothelial function.

• Study Type: Interventional
• Enrollment (Actual): 10
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Pennsylvania
    • Pittsburgh, Pennsylvania, United States, 15261
      • University of Pittsburgh

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 100 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

All participants will be working aged adults (18 years of age or older). Investigators are interested in enrolling public safety workers and healthcare workers given how often this group works night shifts.

Criteria that participants will need to address:

1. 18 years of age or older;
2. Currently licensed or certified as an EMS clinician, other public safety shift worker, or other type of healthcare clinicians and actively working in Western Pennsylvania as an EMT, Paramedic, Flight Nurse/Paramedic, other EMS clinician, firefighter, or other type of healthcare clinician (e.g., nurse, physician, physician assistants, patient care technician, or other healthcare clinician);
3. a 'no' answer to #2 above is not a criterion for exclusion.

Exclusion Criteria:

1. Having ever been diagnosed with the following: hypertension, cardiovascular disease, myocardial infarction, stroke/TIA, chronic kidney disease, liver disease, adrenal disease, thyroid disease, rheumatologic disease, hematologic disease, cancer of any type, dementia/memory loss, organ transplantation; major sleep problem; heavy alcohol use; sleep apnea or other diagnosis that is related to problems with breathing or the airway;
2. Current pregnancy;
3. Insomnia is NOT a criterion for exclusion.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: No-nap, then brief 45-minute nap; Participants will be monitored for a total of 48 hours, including a 12-hour simulated night shift. At baseline (consent), participants are randomized to a crossover study design with two study arms (no nap, brief 45-minute nap). In this sequence, participants will perform the 12-hour simulated night shift with no nap first, undergo a minimum of 1-week washout, then return complete the 48-hour protocol again with the brief 45-minute nap.	Behavioral: Brief on-shift nap; The brief nap opportunity will allow for a 45-minute nap between the hours of 0200 and 0300 during the in-lab 12-hour simulated night shift.
Experimental: The brief 45-minute nap, then no-nap; Participants will be monitored for a total of 48 hours, including a 12-hour simulated night shift. At baseline (consent), participants are randomized to a crossover study design with two study arms (no nap, brief 45-minute nap). In this sequence, participants will perform the 12-hour simulated night shift with the brief 45-minute nap, undergo a 1-week minimum washout, then return to complete the 48-hour protocol again with the no-nap	Behavioral: Brief on-shift nap; The brief nap opportunity will allow for a 45-minute nap between the hours of 0200 and 0300 during the in-lab 12-hour simulated night shift.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants for which at least 70% of required Ambulatory BP readings were collected	A result of at least 10 participants will be considered feasible	48 continuous hours for each arm/condition

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Average blood pressure while awake during simulated night shift	The mean and standard deviation of blood pressure measurements taken while participant is awake during the 12-hour simulated night shift	12 continuous hours for each arm/condition
Average blood pressure while napping during simulated night shift	The mean and standard deviation of blood pressure measurements taken while participant is napping (sleeping) during the 12-hour simulated night shift that includes the 45-minute nap condition.	45 minutes
Average Reactive Hyperemia Index (RHI) at baseline	The mean and standard deviation RHI score for the endothelial dysfunction measurement assessed at baseline	20-30 minutes for each arm/condition
Average Reactive Hyperemia Index (RHI) after simulated night shift	The mean and standard deviation RHI score for the endothelial dysfunction measurement assessed after the 12-hour simulated night shift	20-30 minutes for each arm/condition

Collaborators and Investigators

• Sponsor: University of Pittsburgh
• Investigators: Principal Investigator: P. Daniel Patterson, University of Pittsburgh

Study record dates

Study Major Dates

• Study Start (Actual): June 28, 2022
• Primary Completion (Actual): March 4, 2023
• Study Completion (Actual): March 4, 2023

Study Registration Dates

• First Submitted: June 23, 2022
• First Submitted That Met QC Criteria: June 23, 2022
• First Posted (Actual): June 29, 2022

Study Record Updates

• Last Update Posted (Estimated): January 8, 2024
• Last Update Submitted That Met QC Criteria: January 5, 2024
• Last Verified: January 1, 2024

More Information

Terms related to this study

• Keywords: Endothelial Dysfunction; Ambulatory Blood Pressure
• Other Study ID Numbers: STUDY22040156

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: The investigators do not have an existing plan to share data after the study has been completed. However, the investigators will develop a process to receive requests for de-identified data from outside investigators once the study has been completed.

Drug and device information, study documents

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