Nonstandard time-schedules work are widespread in the world of work. Shift and night work have been shown to be responsible for a desynchronization of biological rhythms, associated with melatonin secretion impairment and sleep disturbances. However, while health consequences of night and shift work are widely recognized and represent a major public health concern (High Authority of Health 2012 Recommendations and National Agency for Public Health Food, Environment and Work 2016 Report), the mechanisms by which the circadian system is affected by shift work remain poorly understood. Indeed most of the studies in the fields are cross-sectional, based on few blood or urinary samples in a single work position, in workers whose shift work patterns are often misidentified and heterogeneous. Moreover, few studies have assessed melatonin secretion alterations in relation to objective sleep measurement (actigraphy). The aim of this study is to assess the dynamics of melatonin secretion adaptation in 12-hour shift work and to correlate these data to sleep-wake cycle recording.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
DIAGNOSTIC
Masking
NONE
Enrollment
15
The study will take place over 15 days during which the nurses will wear an actigraphic wristband and will fulfill a sleep log. During 3 periods of 24 hours selected during these 15 days, including a 12h day shift (Day 2), a 12h night shift (Day 8) and a rest (Day 13), the participants will collect their urine by 4 to 8 hour periods, note the corresponding urine volumes and for each period, sample a 5 mL tube which will be analyzed later (6-sulfatoxymelatonin and urinary cortisol assays). The subjects will complete questionnaires at the beginning of the study (Horne and Ostberg, Insomnia Severity Index, Epworth, Pichot, Hospital Anxiety and Depression) and the days corresponding to the urine sampling (Karolinska and St Mary Hospital).
Croix-Rousse Hospital
Lyon, France
total amount of melatonin excreted during the sleep period for the night shift
The impact of 12H shift work on melatonin secretion dynamics will be assessed by comparing the total amount of melatonin excreted during the sleep period between the 12h day shift condition and the 12h night shift condition
Time frame: at day 8 (night shift)
total amount of melatonin excreted during the sleep period for the day shift.
The impact of 12H shift work on melatonin secretion dynamics will be assessed by comparing the total amount of melatonin excreted during the sleep period between the 12h day shift condition and the 12h night shift condition
Time frame: at day 2 (day shift)
Total amount of melatonin excreted during the sleep period at rest
the total amount of melatonin excreted during the sleep period at rest will be compared to the total amount of melatonin excreted during the sleep period for the 12h day shift condition ant to the total amount of melatonin excreted during the sleep period for the 12h night shift condition
Time frame: at day 13 (rest)
Melatonin secretion dynamics in 12h day shift
Secretion of melatonin on sequential urinary specimens collected every 4 or 8 hours. Measure of total excretion (ng)
Time frame: at day 2 (day shift)
Melatonin secretion dynamics in 12h day shift
Secretion of melatonin on sequential urinary specimens collected every 4 or 8 hours. Measure of acrophase (h)
Time frame: at day 2 (day shift)
Melatonin secretion dynamics in 12h day shift
Secretion of melatonin on sequential urinary specimens collected every 4 or 8 hours. Measure of amplitude (ng)
Time frame: at day 2 (day shift)
Melatonin secretion dynamics in 12h day shift
Secretion of melatonin on sequential urinary specimens collected every 4 or 8 hours. Measure of mesor (ng)
Time frame: at day 2 (day shift)
Melatonin secretion dynamics in 12h night shift
Secretion of melatonin on sequential urinary specimens collected every 4 or 8 hours. Measure of total excretion (ng)
Time frame: at day 8 (night shift)
Melatonin secretion dynamics in 12h night shift
Secretion of melatonin on sequential urinary specimens collected every 4 or 8 hours. Measure of acrophase (h)
Time frame: at day 8 (night shift)
Melatonin secretion dynamics in 12h night shift
Secretion of melatonin on sequential urinary specimens collected every 4 or 8 hours. Measure of amplitude (ng)
Time frame: at day 8 (night shift)
Melatonin secretion dynamics in 12h night shift
Secretion of melatonin on sequential urinary specimens collected every 4 or 8 hours. Measure of mesor (ng)
Time frame: at day 8 (night shift)
Melatonin secretion dynamics at rest
Secretion of melatonin on sequential urinary specimens collected every 4 or 8 hours. Measure of total excretion (ng)
Time frame: at day 13 (rest)
Melatonin secretion dynamics at rest
Secretion of melatonin on sequential urinary specimens collected every 4 or 8 hours. Measure of acrophase (h)
Time frame: at day 13 (rest)
Melatonin secretion dynamics at rest
Secretion of melatonin on sequential urinary specimens collected every 4 or 8 hours. Measure of amplitude (ng)
Time frame: at day 13 (rest)
Melatonin secretion dynamics at rest
Secretion of melatonin on sequential urinary specimens collected every 4 or 8 hours. Measure of mesor (ng)
Time frame: at day 13 (rest)
Cortisol secretion dynamics in 12h day shift
Secretion of cortisol on sequential urinary specimens collected every 4 or 8 hours. Measure of total excretion (ng)
Time frame: at day 2 (day shift)
Cortisol secretion dynamics in 12h day shift
Secretion of cortisol on sequential urinary specimens collected every 4 or 8 hours. Measure of acrophase (h)
Time frame: at day 2 (day shift)
Cortisol secretion dynamics in 12h day shift
Secretion of cortisol on sequential urinary specimens collected every 4 or 8 hours. Measure of amplitude (ng)
Time frame: at day 2 (day shift)
Cortisol secretion dynamics in 12h day shift
Secretion of cortisol on sequential urinary specimens collected every 4 or 8 hours. Measure of mesor (ng)
Time frame: at day 2 (day shift)
Cortisol secretion dynamics in 12h night shift
Secretion of cortisol on sequential urinary specimens collected every 4 or 8 hours. Measure of total excretion (ng)
Time frame: at day 8 (night shift)
Cortisol secretion dynamics in 12h night shift
Secretion of cortisol on sequential urinary specimens collected every 4 or 8 hours. Measure of acrophase (h)
Time frame: at day 8 (night shift)
Cortisol secretion dynamics in 12h night shift
Secretion of cortisol on sequential urinary specimens collected every 4 or 8 hours. Measure of amplitude (ng)
Time frame: at day 8 (night shift)
Cortisol secretion dynamics in 12h night shift
Secretion of cortisol on sequential urinary specimens collected every 4 or 8 hours. Measure of mesor (ng)
Time frame: at day 8 (night shift)
Cortisol secretion dynamics at rest
Secretion of cortisol on sequential urinary specimens collected every 4 or 8 hours. Measure of total excretion (ng)
Time frame: at day 13 (rest)
Cortisol secretion dynamics at rest
Secretion of cortisol on sequential urinary specimens collected every 4 or 8 hours. Measure of acrophase (h)
Time frame: at day 13 (rest)
Cortisol secretion dynamics at rest
Secretion of cortisol on sequential urinary specimens collected every 4 or 8 hours. Measure of amplitude (ng)
Time frame: at day 13 (rest)
Cortisol secretion dynamics at rest
Secretion of cortisol on sequential urinary specimens collected every 4 or 8 hours. Measure of mesor (ng)
Time frame: at day 13 (rest)
Objective sleep quality
Measure of sleep latency assessed by sleep log
Time frame: 15 days
Objective sleep quality
Measure of sleep latency assessed by actigraphy
Time frame: 15 days
Objective sleep quality
Measure of sleep efficiency = total sleep / bedtime assessed by sleep log
Time frame: 15 days
Objective sleep quality
Measure of sleep efficiency = total sleep / bedtime assessed by actigraphy
Time frame: 15 days
Objective sleep quality
Measure of fragmentation index assessed by sleep log
Time frame: 15 days
Objective sleep quality
Measure of fragmentation index assessed by actigraphy
Time frame: 15 days
Objective sleep quality
Measure of intra-sleep wakefulness assessed by sleep log
Time frame: 15 days
Objective sleep quality
Measure of intra-sleep wakefulness assessed by actigraphy
Time frame: 15 days
Objective sleep duration
duration of sleep assessed by actigraphy
Time frame: 15 days
Excessive daytime sleepiness
This outcome will be assessed by the Epworth sleepiness Scale
Time frame: at day 1
Asthenia
This outcome will be assessed by the Pichot asthenia scale
Time frame: at day 1
Insomnia severity
This outcome will be assessed by the Insomnia Severity Index
Time frame: at day 1
Anxiety
This outcome will be assessed by the Hospital Anxiety and Depression scale
Time frame: at day 1
Depression
This outcome will be assessed by the Hospital Anxiety and Depression scale
Time frame: at day 1
Vigilance at awakening
This outcome will be assessed by the Karolinska scale
Time frame: at day 2, 8 and 13
Sleep subjective quality
This outcome will be assessed by the St Mary Hospital Questionary
Time frame: at day 2, 8 and 13
Chronotype
This outcome will be assessed by the Horne and Ostberg Questionary
Time frame: at day 1
Light exposition
This outcome will be assessed by the actigraphy
Time frame: 15 days
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