Table 1.
Central clock markers in shift workers.
| References | Population | Tissue and Circadian Markers | Observations |
|---|---|---|---|
| Barnes et al. (1998) | Offshore oil-rig workers | Urine: 6-sulfatoxymelatonin | Phase: ~1.5 h/day partial phase shift |
| Goh et al. (2000) | Navy personnel | Saliva: Melatonin | Mesor: 17% ↓ Profile: 19% distorted peaks/troughs Phase: 52% profiles misaligned, 12% partial delay |
| Saliva: Cortisol | Profile: Disrupted peaks and troughs in night work | ||
| Zuzewicz et al. (2000) | Air traffic controllers | Urine: Cortisol | Mesor: ↓ during night vs. day shifts |
| Yamauchi et al. (2001) | Shift-working nurses | Urine: 6-sulfatoxymelatonin | Phase: ↓ at night for night vs. day shifts |
| Gibbs et al. (2002) | Offshore oil-rig workers | Urine: 6-sulfatoxymelatonin | Phase: 5.4 h phase delay after 7 night shifts |
| Lac and Chamoux (2004) | Process control worker | Saliva: Cortisol | Mesor: ↓ peak for night vs. day shifts Phase: Later peak on 3rd night vs. day shift (1100 h vs. 0700 h) |
| Hansen et al. (2006) | Nurses | Urine: 6-sulfatoxymelatonin | Mesor: ↓ for night vs. day shifts |
| Gibbs et al. (2007) | Offshore oil-rig workers | Urine: 6-sulfatoxymelatonin | Phase: 83% > 3 h phase delay after 7 night shifts |
| Kudielka et al. (2007) | Manufacturing workers | Saliva: Cortisol | Profile: ↓ awakening response after night shifts Phase: n.s. between fixed and rotating night workers |
| Grundy et al. (2009) | Nurses | Saliva: Melatonin | Phase: Peak between 2300 h and 0700 h for night and day shifts |
| Urine: 6-sulfatoxymelatonin | Profile: ↓ upon awakening after night vs. day shifts | ||
| Hansen et al. (2010) | Offshore oil-rig workers | Urine: 6-sulfatoxymelatonin | Phase: 4 h delay after 7 nights |
| Harris et al. (2010) | Offshore oil-rig workers | Saliva: Cortisol | Profile: ↓ awakening response when working nights vs. days. n.s. timing of peak relative to awakening |
| Grundy et al. (2011) | Nurses | Saliva: Melatonin | Phase: Peak between 2300 h and 0700 h for both night and day shifts |
| Urine: 6-sulfatoxymelatonin | Profile: Similar morning excretion after night vs. day shifts | ||
| Leichtfried et al. (2011) | Doctors and medical students | Urine: 6-sulfatoxymelatonin | Profile: ↓ peak between 1900 h and 2300 h of 24 h shifts Phase: Peak in same 4 h time bin before and after 24 h shifts |
| Dumont et al. (2012) | Telecommunication workers | Urine: 6-sulfatoxymelatonin | Mesor: Similar 24 h excretion in night and day shifts Profile: ↓ during day vs. night sleep periods |
| Ferguson et al. (2012) | Remote mining operators | Saliva: Melatonin | Phase: ~30 min delay after 7 night vs. day shifts |
| Peplonska et al. (2012) | Nurses and midwives | Urine: 6-sulfatoxymelatonin | Profile: Similar between 0600 h-0800 h after night or day shifts |
| Bostock and Steptoe (2013) | Short-haul airline pilots | Saliva: Cortisol | Profile: ↓ awakening response for late vs. early shifts |
| Mirick et al. (2013) | Health care workers | Urine: 6-sulfatoxymelatonin | Profile: ↓ during day vs. night sleep periods |
| Urine: Cortisol | Profile: ↑ during day vs. night sleep periods | ||
| Serum: Cortisol | Profile: ↓ morning levels after night shifts | ||
| Papantoniou et al. (2014) | Assorted occupations/industries | Urine: 6-sulfatoxymelatonin | Mesor: ↓ for night workers Amp.: ↓ for night workers Phase: Later for night vs. day workers (0842 h vs. 0536 h) |
| Gomez-Acebo et al. (2015) | Nurses and teachers | Urine: 6-sulfatoxymelatonin | Mesor: ↓ for rotating night workers Amp.: ↓ for rotating night workers Phase: Later for night vs. day shifts (0831 h vs. 0713 h) |
| Serum: Cortisol | Profile: n.s. morning levels for night and day workers | ||
| Niu et al. (2015) | Nurses | Saliva: Cortisol | Profile: ↓ awakening response for 4 night shifts |
| Bracci et al. (2016) | Nurses | Wrist skin temperature | Mesor: ↑ for shift workers Amp.: ↓ for shift workers Phase: n.s. |
| Saliva: Melatonin | Profile: n.s. Phase: Peak in same 3 h bin for shift and day workers |
||
| Saliva: Cortisol | Profile: ↓ peak for shift workers Phase: Peak in same 3 h bin for shift and day workers |
||
| Hung et al. (2016) | Hospital employees | Urine: Cortisol | Mesor: 16.7% ↓ for night vs. day workers Profile: Flatter rhythm for night vs. day shifts |
| Jensen et al. (2016) | Police officers | Saliva: Melatonin | Profile: ↓ peak after 4 nights Phase: n.s. |
| Saliva: Cortisol | Profile: n.s Phase: 8.83 h (2nd night) to 11.52 h (7th night) delay |
||
| Leung et al. (2016) | Hospital employees | Urine: 6-sulfatoxymelatonin | Mesor: ↓ after 1 night shift Phase: Earlier in night vs. day shifts (0343 h vs. 0423 h) |
| Morris et al. (2016) | Current self-identified shift workers | Blood: Melatonin | Phase: n.s. |
| Daugaard et al. (2017) | Assorted occupations/industries | Saliva: Melatonin | Mesor: 15% ↓ for night vs. day workers Phase: n.s. |
| Jang et al. (2017) | Manufacturing company employees | Wrist skin temperature | Mesor: n.s. Amp.: ↓ for shift vs. day workers Phase: Later for shift vs. day workers (0803 h vs. 0411 h) |
| Stone et al. (2018) | Physicians and nurses | Urine: 6-sulfatoxymelatonin | Phase: 1.1 h delay for 3rd/4th shifts (0421 vs. 0518 h) |
| Koshy et al. (2019) | Police officers | Saliva: Cortisol | Profile: ↓ difference between wake and bedtimes after 7 night shifts |
| Urine: 6-sulfatoxymelatonin | Mesor: ↓ after night shifts Amp.: ↓ after night shifts Phase: 7.6 h phase delay after 7 nights (0425 h vs. 1159 h) |
||
| Molzof et al. (2019) | Nurses | Core body temperature | Phase: Delayed for night vs. day shifts (0816 h vs. 0252 h) |
| Razavi et al. (2019) | Nurses | Urine: 6-sulfatoxymelatonin | Mesor: ↓ for night vs. day workers Profile: ↓ peak for night vs. day workers Phase: Delayed for night vs. day workers (0543 h vs. 0406 h) |
Abbreviation: n.s. = non-significant. Studies were screened for results on mesor, amplitude (amp.), and acrophase (phase). When the amplitude was not available, profile information, such as peak modifications and rhythm distortions, were reported. All studies were conducted in the field, with one exception (i.e., Morris et al., 2016). Clock times expressed in 24-h time format hhmm.