Monitoring Sleep, Wellbeing, and Glucose Metabolism in PGY1s

Study Overview
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Brief Summary
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Overnight on-call schedules can impact sleep, wellbeing, and alertness, which can be detrimental on the performance, physical and mental health of residents. Moreover, rotating shift work may have a long-term negative health impact (e.g. increased risk of diabetes). Within the National University Hospital (NUH), two different systems of rotating on-call schedules are implemented. In the night float system, residents work from 8 pm to 8 am for 5 - 7 consecutive nights once every month, compared to the traditional overnight on-call system, where each resident is on call for 4-6 nights per month (7 am - 5 pm, followed by overnight call until 8 am the next morning). The aim of the current study is to track sleep, wellbeing, and glucose metabolism during the different phases of the night float and traditional on-call schedules.

Detailed Description
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Overnight on-call schedules can impact sleep, wellbeing, and alertness, which can be detrimental on the performance, physical and mental health of residents. Moreover, rotating shift work may have a long-term negative health impact (e.g. increased risk of diabetes). Within the National University Hospital (NUH), two different systems of rotating on-call schedules are implemented. In the night float system, residents work from 8 pm to 8 am for 5 - 7 consecutive nights once every month, compared to the traditional overnight on-call system, where each resident is on call for 4-6 nights per month (7 am - 5 pm, followed by overnight call until 8 am the next morning). The aim of the current study is to track sleep, wellbeing, and glucose metabolism during the different phases of the night float and traditional on-call schedules. The availability of accurate mobile methodologies to monitor sleep and metabolic health provide new avenues for the improvement of sleep health and well-being. Wearable sleep tracking devices and smartphone apps provide remarkable opportunities for non-invasive, longitudinal sleep detection. Measurement of sleep during different stages of the shift schedule (baseline, on-call, recovery) can provide detailed insights into the temporal impact of the different schedules. Moreover, self-reported ratings of sleep quality, wellbeing, and time-use (delivered through phone-based e-diary methods) can further detail the mental health impact associated with these schedules. Wearable continuous glucose monitoring systems (CGMS) provide a minimally invasive means of passively tracking ambulant interstitial fluid glucose levels in real time.

Official Title
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Monitoring Sleep, Wellbeing, and Glucose Metabolism in Postgraduate Year 1 Doctors on Traditional and Float Call Shifts

Conditions
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Sleep, Glucose Metabolism Disorders

Intervention / Treatment
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* Device: CGM
* Device: Oura ring
* Behavioral: Cognitive tasks and questionnaires


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: NUHS Postgraduate year 1 doctors Above 21 years of age Completing their year 1 rotations in 2021 or 2022 Exclusion Criteria: As this is an observational study with minimal risk, in an restricted pool of participants, no further exclusion criteria will be applied for participation.

Ages Eligible for Study
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Minimum Age: 21 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Traditional call<br>In the traditional overnight on-call system, each resident is on call for 4-6 nights per month (7 am - 5 pm, followed by overnight call until 8 am the next morning) | Device: CGM<br>* Wearable continuous glucose monitoring systems (CGMS) provide a minimally invasive means of passively tracking ambulant interstitial fluid glucose levels in real time.<br>Device: Oura ring<br>* Wearable sleep tracking device<br>Behavioral: Cognitive tasks and questionnaires<br>* Participants will be prompted daily to fill out a short set of wellbeing questions and perform a short alertness test on their mobile phones and laptop.<br>|
| Float call<br>In the night float system, residents work from 8 pm to 8 am for 5 - 7 consecutive nights once every month | Device: CGM<br>* Wearable continuous glucose monitoring systems (CGMS) provide a minimally invasive means of passively tracking ambulant interstitial fluid glucose levels in real time.<br>Device: Oura ring<br>* Wearable sleep tracking device<br>Behavioral: Cognitive tasks and questionnaires<br>* Participants will be prompted daily to fill out a short set of wellbeing questions and perform a short alertness test on their mobile phones and laptop.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sleep | Sleep duration and timing will be measured | 8 weeks | 
| Wellbeing | Participants will complete a daily micro questionnaire delivered through a mobile phone-based application. The investigators will examine mood ratings and stress ratings. Participants will be asked to respond to questions such as How are you feeling right now?, rating their response from 'Negative' to 'Positive' on a 100-points sliding bar, How stressed are you feeling right now?, rating their response from 'Not at all stressed' to 'Very stressed' on a 100-points sliding bar. | 8 weeks | 
| Glucose monitoring | Blood glucose will be recorded using a wearable continuous glucose monitoring sensor (CGM: FreeStyle Libre Pro iQ by Abbott). CGM period will be individually scheduled to coincide with at least one cycle of day shift-night shift- recovery for each participant. | 2 weeks | 
| Alertness | Participants will complete a daily set of cognitive games, delivered through a mobile phone-based application. The outcome measure from the games is a 3-min psychomotor vigilance task measuring sustained attention. Specifically, the investigators examine median reaction time and lapses (reaction time > 500ms). | 8 weeks |