Sleep and Circadian Treatments for Shift Workers

NCT03813654 | Terminated Results

• 2 other identifiers: 2018-P-002341R01AG044416
• Study Type: interventional
• Target: 33
• Locations: 1 country
• Sites: 1

Brief Summary

There are three components to this study: a Field Trial, a Shift Worker Survey, and Focus Groups. The Investigators will study the effectiveness, feasibility, and acceptability of an 8-h sleep intervention in older night workers in an operational environment. The overall goal of the Field Trial is to minimize sleep deficiency and negative outcomes resulting from that, including sleepiness and performance impairments during night shift work. The Shift Worker Survey is designed to understand some of the demographic and operational factors that enable or inhibit the ability of individual shift workers to adopt this intervention. The Focus Groups are designed to glean in-depth information from older shift workers who indicate that they are unable or unwilling to adopt an 8-h sleep timing intervention. Understanding these factors will assist in refining and targeting the intervention to those individuals who will be most likely to benefit from the intervention sleep timing strategy.

Conditions

Shift-Work Sleep Disorder; Shift-Work Related Sleep Disturbance

Keywords

sleep; attention; vigilance; aging; shift work

Outcome Measures

Primary Outcomes (11)

• Total Sleep Time (TST)

  TST is calculated as minutes of sleep in the main sleep episode between shifts, derived from actigraphy data collected in 60 s epochs. The investigators will use a commercial software package to score the sleep. For control group participants who will sleep ad-lib, TST will be calculated for the major sleep episode but also will be summed across sleep episodes if they sleep in more than one bout.

  The TST averaged for up to 3 intervention nights (in minutes) will be compared between groups.

• Sleep Fragmentation Index (FI)

  FI will be calculated as the number of times that sleep was terminated after 1 minute, expressed as a percentage of total estimated sleep time, using actigraphy data and commercial software to calculate it.

  The FI averaged for intervention nights 2 and 3 will be compared between groups.

• Wake After Sleep Onset (WASO)

  WASO is an objective sleep quality measure and will be calculated as the duration (in minutes) of all awakenings during the main sleep episode measured with actigraphy, and calculated using commercial software.

  The WASO averaged for intervention nights 2 and 3 will be compared between groups.

• Subjective Sleep Quality

  Participants will report their subjective sleep quality daily upon awakening from the main sleep episode. Multiple measures of subjective sleep quality will be assessed, but the investigators will report how refreshed the participant feels after awakening as the outcome. This is rated on a 7-point scale, where 7 is the best and 1 is the worst.

  Subjective Sleep quality (refreshment) averaged for intervention nights 2 and 3 will be compared between groups.

• Subjective Alertness Via Karolinska Sleepiness Scale (KSS)

  Participants will complete the Karolinska Sleepiness Scale (KSS) as a measure of subjective alertness immediately following each night shift. The KSS is a Likert scale ranging from 1, extremely alert, to 9, extremely sleepy.

  The KSS score taken at the end of the final night shift (night shift 3) during the intervention block will be compared to that at baseline.

• Sustained Attention

  The psychomotor vigilance task (PVT) is a test of visual reaction time (RT) in which the participant is asked to maintain the fastest possible RTs to a simple visual stimulus for several minutes. The inter-stimulus interval varies randomly between 2-10 seconds. While there are a number of standard performance metrics that can be obtained from each PVT, we have looked at the slowest 10% of responses.

  PVT mean of slowest 10% of responses measured at the start of the final night shift (night shift 3) during the intervention block will be compared between groups.

• Subjective Energy

  A Visual Analogue Scale (VAS) will be used to assess subjective energy level. The VAS consists of a 100mm horizontal line with each end of the line labeled with the extremes of a subjective continuum, e.g. energetic-sluggish. The Participant indicates a position on the line that best describes how they feel at that moment. Distance from the left end of the scale (0) to the indicated point will be measured in mm and reported as subjective energeticness. Thus, scores on the scale range from 0 to 100 with lower scores indicating greater subjective energy.

  Subjective Energy measurements taken at the end of the final night shift (night shift 3) in the intervention block will be compared between groups.

• Subjective Stress Via Visual Analog Scale (VAS)

  A Visual Analogue Scale (VAS) will be used to assess subjective stress.The VAS consists of a 100mm horizontal line with each end of the line labeled with the extremes of a subjective continuum, e.g. relaxed-stressed. The Participant indicates a position on the line that best describes how they feel at that moment. Distance from the left end of the scale (0) to the indicated point will be measured in mm and reported as Subjective Stress. Thus, scores on the scale range from 0 to 100 with higher scores indicating greater subjective stress.

  Subjective Stress via VAS measurements taken at the end of the final night shift (night shift 3) in the intervention block will be compared between groups.

• Subjective Calmness Via Visual Analog Scale (VAS)

  A Visual Analogue Scale (VAS) will be used to assess subjective Calmness. The VAS consists of a 100mm horizontal line with each end of the line labeled with the extremes of a subjective continuum, e.g. calm-excited. The Participant indicates a position on the line that best describes how they feel at that moment. Distance from the left end of the scale (0) to the indicated point will be measured in mm and reported as Subjective Calmness. Thus, scores on the scale range from 0 to 100 with lower scores indicating greater subjective calmness.

  Subjective Calmness via VAS measurements taken at the end of the final night shift (night shift 3) in the intervention block will be compared between groups.

• Subjective Health Via Visual Analog Scale (VAS)

  Visual Analogue Scales (VAS) will be used to assess subjective health. VAS consist of a 100mm horizontal line with each end of the line labeled with the extremes of a subjective continuum, e.g. healthy-sick. The Participant indicates a position on the line that best describes how they feel at that moment. Distance from the left end of the scale (0) to the indicated point will be measured in mm and reported as Subjective Health. Thus, scores on the scale range from 0 to 100 with lower scores indicating greater subjective health.

  Subjective Health via VAS measurements taken at the end of the final night shift (night shift 3) in the intervention block will be compared between groups.

• Subjective Alertness Via Visual Analog Scale (VAS) - DATA NOT COLLECTED

  Participants will complete the Visual Analog Scale (VAS) as a measure of subjective alertness three times per night shift: Once just before the night shift, once during their shift break, and once immediately following the night shift. The VAS consists of a 100mm horizontal line with each end of the line labeled with the extremes of a subjective continuum, e.g. sleepy-alert. Participants will indicate a position on the line that best describes how they feel at that moment. Distance from the left end of the scale to the indicated point will be measured in mm and reported as Subjective Alertness with higher scores indicating greater subjective alertness.

  Subjective Alertness via VAS measurements taken at the end of the final night shift (night shift 3) in the intervention block will be compared between groups.

Secondary Outcomes (4)

• Fatigue and Inter-Shift Recovery

  OFER15 scores from the end of the third night shift in the Baseline to the end of the Intervention block will be compared between groups.

• Subjective Stress

  Subjective stress will be assessed immediately after the third night shift in the Baseline and Intervention blocks and the change will be compared between groups.

• Subjective Quality of Life: WHOQOLBref

  WHOQOL-Bref will be taken at Baseline and immediately after the third night shift in the Intervention block and will be compared between groups.

• Salivary Cortisol Level NOTE THAT THIS AIM WAS DROPPED WHEN THE STUDY WENT TO FULLY REMOTE DUE TO COVID

  Salivary Cortisol will be assessed immediately after the third night shift in the Intervention block and levels will be compared between groups.

Study Arms (3)

Control (Group A)

NO INTERVENTION

During the intervention block of the Field Trial, at the end of the first night shift, the participant will be told about their randomization group. In the control group (Group A), participants will not be given any instructions about the timing or duration of their sleep, but will be instructed to follow their usual night shift sleep routine.

8-h Afternoon-Evening Sleep (Group B)

EXPERIMENTAL

In the 8-h afternoon-evening sleep intervention group (Group B), participants will be instructed to go to bed between 13:00 and 14:00 (depending on their individual commute time) and to remain in bed attempting to sleep for 8 hours (until 21:00-22:00) before the next two night shifts.

Behavioral: 8-h Afternoon-Evening Sleep

8-h Free Sleep (Group C)

EXPERIMENTAL

In the 8-h free sleep group (Group C), participants will be instructed to remain in bed for 8 continuous hours before the next two night shifts, but will not be given any instruction regarding which 8 hours they should sleep.

Behavioral: 8-h Free Sleep

Interventions

8-h Afternoon-Evening Sleep BEHAVIORAL

8 consecutive hours time in bed during the afternoon/evening.

8-h Afternoon-Evening Sleep (Group B)

8-h Free Sleep BEHAVIORAL

8 consecutive hours time in bed at any time.

8-h Free Sleep (Group C)

Eligibility Criteria

• Age: 50 Years - 65 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age 50-65 years
• Health care workers who work a minimum of 4 night shifts (8-4) per month
• Must live in the greater Boston area
• Must report an ability to work three successive 8-h night shifts during two weeks
• Must report an ability to spend 8 consecutive hours in bed attempting to sleep prior to the final two successive night shifts in the second study week
• Must have a typical commute time between home and place of work of less than one hour

You may not qualify if:

• Non-optional activities that would interfere with the participant's ability to remain in bed attempting to sleep if randomized to an 8-h sleep group
• Prescription or over-the-counter medication(s) known to affect sleep \[e.g., hypnotics\] or alertness \[e.g., antihistamines\]

Sponsors & Collaborators

• Brigham and Women's Hospital: lead
• National Institute on Aging (NIA): collaborator
• University of Massachusetts, Lowell: collaborator

Study Sites (1)

Brigham and Women's Hospital

Boston, Massachusetts, 02115, United States

Location

MeSH Terms

Conditions

Sleep Disorders, Circadian Rhythm

Condition Hierarchy (Ancestors)

Chronobiology Disorders; Nervous System Diseases; Dyssomnias; Sleep Wake Disorders; Occupational Diseases; Mental Disorders

Limitations and Caveats

Enrollment in the study was hindered by the COVID-19 pandemic, and we had fewer participants than originally planned. We changed the study to be fully remote due to COVID and had to drop the salivary cortisol aim. Due to lower enrollment than planned, we could not address many of the secondary aims.

Results Point of Contact

• Title: Jeanne F. Duffy, Principal Investigator
• Organization: Brigham and Women's Hospital

jduffy@bwh.harvard.edu

617-732-7995

Study Officials

• Jeanne F Duffy, MBA, PhD

  Brigham and Women's Hospital

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: No
• Restrictive Agreement: No

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: HEALTH SERVICES RESEARCH
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Model Details: The interventional study design describes the Field Trial only.

Study Record Dates

• First Submitted: January 8, 2019
• First Posted: January 23, 2019
• Study Start: August 20, 2020
• Primary Completion: October 1, 2023
• Study Completion: December 31, 2023
• Last Updated: August 15, 2025
• Results First Posted: August 15, 2025

Record last verified: 2025-07

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)