Predicting Circadian Response to Abrupt Phase Shift: 6-Sulphatoxymelatonin Rhythms in Rotating Shift Workers Offshore

Gibbs, M.; Hampton, Shelagh M.; Morgan, Linda; Arendt, Joséphine

doi:10.1177/0748730407302843

Cited by 45 publications

(59 citation statements)

References 10 publications

(13 reference statements)

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“…While this may be a potential limitation to the research, the method is well-established in the literature as a suitable real-world assessment of circadian phase, of which the techniques and protocols used here have been applied successfully in several prior studies of shift workers on North Sea oil rigs, [45][46][47][48][49] in shift working nurses, [50][51][52] in shift workers living in Antarctica, 53,54 and in many clinical populations and experimental protocols. 35,[55][56][57][58] To assess the potential impact of light on aMT6s, in a previous study we compared aMT6s with urinary cortisol (which is much less confounded by light) in a subset of sighted individuals (n = 7) and found a strong relationship between the phase estimates (average Pearson r ± SD, 0.98 ± 0.01, p < 0.05).…”

Section: Discussionmentioning

confidence: 99%

Ocular Measures of Sleepiness Are Increased in Night Shift Workers Undergoing a Simulated Night Shift Near the Peak Time of the 6-Sulfatoxymelatonin Rhythm

Ftouni

Nicholas

Kennaway

et al. 2015

Journal of Clinical Sleep Medicine

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Study Objectives:The study examined the relationship between the circadian rhythm of 6-sulphatoxymelatonin (aMT6s) and ocular measures of sleepiness and neurobehavioral performance in shift workers undergoing a simulated night shift. Methods: Twenty-two shift workers (mean age 33.4, SD 11.8 years) were tested at approximately the beginning (20:00) and the end (05:55) of a simulated night shift in the laboratory. At the time point corresponding to the end of the simulated shift, 14 participants were classifi ed as being within range of 6-sulphatoxymelatonin (aMT6s) acrophasedefi ned as 3 hours before or after aMT6s peak-and 8 were classifi ed as outside aMT6s acrophase range. Participants completed the Karolinska Sleepiness Scale (KSS) and the auditory psychomotor vigilance task (aPVT). Waking electroencephalography (EEG) was recorded and infrared refl ectance oculography was used to collect ocular measures of sleepiness: positive and negative amplitude/velocity ratio (PosAVR, NegAVR), mean blink total duration (BTD), the percentage of eye closure (%TEC), and a composite score of sleepiness levels (Johns Drowsiness Scale; JDS).Results: Participants who were tested within aMT6s acrophase range displayed higher levels of sleepiness on ocular measures (%TEC, BTD, PosAVR, JDS), objective sleepiness (EEG delta power frequency band), subjective ratings of sleepiness, and neurobehavioral performance, compared to those who were outside aMT6s acrophase range. Conclusions:The study demonstrated that objective ocular measures of sleepiness are sensitive to circadian rhythm misalignment in shift workers. Keywords: oculometrics, circadian misalignment, shift work, performance, sleepiness Citation: Ftouni S, Sletten TL, Nicholas CL, Kennaway DJ, Lockley SW, Rajaratnam SM. Ocular measures of sleepiness are increased in night shift workers undergoing a simulated night shift near the peak time of the 6-sulfatoxymelatonin rhythm. J Clin Sleep Med 2015;11(10):1131 -1141 .pii: jc-00268-14 http://dx.doi.org/10.5664/jcsm.5086 S hift work has become a ubiquitous part of labor practices due to the increasing pressure for 24-hour provision of goods and services. This drive for round-the-clock productivity, however, has resulted in negative consequences to health, safety, and performance.1 Such consequences have been welldocumented in a number of occupational sectors in which peak functioning during the night shift is critical, for example, commercial transport, mining, emergency services, and health care. The impairment to alertness that occurs during night shift work is mainly attributed to misalignment of the imposed sleep-wake cycle from the internally generated circadian (~24-hour) rhythm of sleepiness, 3 often against a background of chronic sleep defi ciency and prolonged periods of wakefulness. Alertness and neurobehavioral performance peak when the circadian pacemaker promotes wakefulness during the daytime, and decline markedly during the night, particularly between 03:00 and 06:00, 4 as the circadian pacemaker strongly promotes...

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Section: Discussionmentioning

confidence: 99%

Ocular Measures of Sleepiness Are Increased in Night Shift Workers Undergoing a Simulated Night Shift Near the Peak Time of the 6-Sulfatoxymelatonin Rhythm

Ftouni

Nicholas

Kennaway

et al. 2015

Journal of Clinical Sleep Medicine

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“…Morning preference has been associated with an earlier melatonin peak time (26,27,39,42). Individual circadian phase assessed by melatonin timing (21,25) and chronotype has been associated with workers' adaptability to shift-work schedules (24). Evening types report better tolerance for night work and quicker adaptation (shift of the circadian rhythms) than morning types (20).…”

Section: <0001mentioning

confidence: 99%

“…Diurnal preference is suggested to affect shift work adaptation (24). Evening types (subjects with a later melatonin peak) may adapt faster to night shift work by phase delaying their circadian rhythms (21,(25)(26)(27), but this is still an understudied hypothesis.…”

Section: Introductionmentioning

confidence: 99%

Circadian Variation of Melatonin, Light Exposure, and Diurnal Preference in Day and Night Shift Workers of Both Sexes

Papantoniou

Pozo

Espinosa

et al. 2014

Cancer Epidemiology, Biomarkers &Amp; Prevention

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Background: Light-at-night has been shown in experimental studies to disrupt melatonin production but this has only partly been confirmed in studies of night shift workers. In this cross-sectional study, we examined the circadian variation of melatonin in relation to shift status, individual levels of light-at-night exposure, and diurnal preference, an attribute reflecting personal preference for activity in the morning or evening.Methods: One hundred and seventeen workers (75 night and 42 day) of both sexes, ages 22 to 64 years, were recruited from four companies. Participants collected urine samples from all voids over 24 hours and wore a data logger continuously recording their light exposure. Sociodemographic, occupational, lifestyle, and diurnal preference information were collected by interview. Concentrations of urinary 6-sulfatoxymelatonin (aMT6s), the main melatonin metabolite, were measured.Results: Mean aMT6s levels were lower in night [10.9 ng/mg creatinine/hour; 95% confidence interval (CI), 9.5-12.6] compared with day workers (15.4; 95% CI, 12.3-19.3). The lowest aMT6s levels were observed in night workers with morning preference (6.4; 95% CI, 3.0-13.6). Peak time of aMT6s production occurred 3 hours later in night (08:42 hour, 95% CI, 07:48-09:42) compared with day workers (05:36 hour, 95% CI, 05:06-06:12). Phase delay was stronger among subjects with higher light-at-night exposure and number of nights worked.Conclusions: Night shift workers had lower levels and a delay in peak time of aMT6s production over a 24-hour period. Differences were modified by diurnal preference and intensity of light-at-night exposure.Impact: Night shift work affects levels and timing of melatonin production and both parameters may relate to future cancer risk. Cancer Epidemiol Biomarkers Prev; 23(7); 1176-86. Ó2014 AACR.

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“…Four out of five prospective cohort studies among women without night work have shown increased risk of breast cancer related to low urine levels of the melatonin metabolite, 6-sulfatoxymelatonin in morning spot samples or 24 hour samples (12)(13)(14)(15)(16). Unfortunately there are only few studies that in some detail outline the melatonin exposure profile (peak, amplitude, duration, timing) among people working night shifts (17)(18)(19)(20) except among nurses working in fastforward-rotating shifts (21). These studies report a small reduction (typically less than 20%) in melatonin secretion and a flattened secretion profile among night compared to day workers.…”

Section: Light Circadian Rhythms and Melatoninmentioning

confidence: 99%

Work at night and breast cancer – report on evidence-based options for preventive actions

Bonde¹,

Hansen²,

Kolstad³

et al. 2012

Scand J Work Environ Health

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Predicting Circadian Response to Abrupt Phase Shift: 6-Sulphatoxymelatonin Rhythms in Rotating Shift Workers Offshore

Cited by 45 publications

References 10 publications

Ocular Measures of Sleepiness Are Increased in Night Shift Workers Undergoing a Simulated Night Shift Near the Peak Time of the 6-Sulfatoxymelatonin Rhythm

Ocular Measures of Sleepiness Are Increased in Night Shift Workers Undergoing a Simulated Night Shift Near the Peak Time of the 6-Sulfatoxymelatonin Rhythm

Circadian Variation of Melatonin, Light Exposure, and Diurnal Preference in Day and Night Shift Workers of Both Sexes

Work at night and breast cancer – report on evidence-based options for preventive actions

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