Shift work and pathological conditions

Downside of Helping Professions: A Comparative Study of Health Indicators and Health Behaviour among Nurses and Early Childhood Educators

The activities of health care workers and early childhood educators have received increased attention both in lay public discourse and in scientific discourse. These professional groups play a significant role in shaping the health behaviours of those they interact with; thus, understanding the patterns they convey is of paramount importance. The aim of our study is a comparative analysis of health conditions and health behaviours of professionals working in Hungarian early childhood education and nurses working in the healthcare system (n = 1591). We carried out our quantitative, cross-sectional research using convenience sampling among healthcare professionals working in nursing job positions (n = 581) and as early childhood educators (n = 1010), in south-west Hungary. Diagnosed chronic illnesses affect early childhood educators at a significantly higher rate (p < 0.05): the prevalence of musculoskeletal disorders is particularly high among them, as a result of which they reported a significant degree of physical limitation in relation to work. In the context of mental health, comparing the professional groups, nurses' indicators were significantly (p < 0.001) more unfavourable in all examined dimensions. Moreover, the comparison in terms of educational attainment directed attention to the worse indicators of non-graduates. In this context, early childhood educators are less affected by all three dimensions of burnout (p < 0.001). As for health behaviour, the smoking habits of nurses are more unfavourable (p < 0.05). Regarding screening tests, participation in cytological testing was significantly higher among nurses, whereas early childhood educators showed increased participation in mammography (p < 0.001). Our findings draw attention to the fact that early childhood educators are primarily affected by chronic musculoskeletal disorders, while healthcare workers are more affected by problems related to mental health. Mental well-being can be further endangered by the fact that both professional groups perceive low social appreciation for the work they carry out.

Impact of shift work on sleep and fatigue in Maritime pilots

This study examined how objective measures of sleep change across shift-cycles, and the impact of this on sleep quality and fatigue. Forty maritime pilots were recruited from Australian ports. Sleep wake-behaviour (timing and length), and self-reported sleep quality and fatigue, were assessed to determine any impact of roster status and 'on-call' status. On-roster pilots experienced reduced night time sleep duration compared to those off-roster (57 ± 8.8 min), while working on-call also diminished night time sleep duration (126 ± 11.3 min) and quality, compared to workers not on-call. Fatigue scores indicated that participants were not fully recovered prior to commencing rostered night shift, while sleep quality was significantly worse following sleep that occurred after a night shift, compared to after a day shift. These findings potentially support workplace negotiations to change future shift cycles, and to adopt monitoring systems that may mitigate the risk of fatigue-related accidents and chronic health outcomes. Practitioner summary: Long and irregular work hours of maritime pilotage can compromise worker performance and safety. This observational study found that on-roster pilots experience reduced sleep duration compared to those off-roster, while working on-call further diminishes sleep duration and quality. Future workload/fatigue monitoring systems may mitigate fatigue-related accidents and adverse chronic health outcomes. Abbreviations: ANOVA: analysis of variance; ANCOVA: analysis of covariance; BMI: body mass index; CVD: cardiovascular disease; h: hours; mins: minutes; SE: standard error of the mean; SD: standard deviation; SO: sleep opportunities; TST: total sleep time; WASO: wake after sleep onset.

Obesity and shift work: chronobiological aspects

The present review has the objective of summarising chronobiological aspects of shift work and obesity. There was a systematic search in PubMed databases, using the following descriptors: shift work; obesity; biological clock. Shift work is extremely frequent in several services and industries, in order to systematise the needs for flexibility of the workforce, necessary to optimise productivity and business competitiveness. In developing countries, this population represents a considerable contingent workforce. Recently, studies showed that overweight and obesity are more prevalent in shift workers than day workers. In addition, the literature shows that shift workers seem to gain weight more often than those workers submitted to a usual work day. In conclusion, there is considerable epidemiological evidence that shift work is associated with increased risk for obesity, diabetes and CVD, perhaps as a result of physiological maladaptation to chronically sleeping and eating at abnormal circadian times. The impact of shift work on metabolism supports a possible pathway to the development of obesity and its co-morbities. The present review demonstrated the adverse cardiometabolic implications of circadian misalignment, as occurs chronically with shift workers.

Physiological responses of the circadian clock to acute light exposure at night

Circadian rhythms in physiological, endocrine and metabolic functioning are controlled by a neural clock located in the suprachiasmatic nucleus (SCN). This structure is endogenously rhythmic and the phase of this rhythm can be reset by light information from the eye. A key feature of the SCN is that while it is a small structure containing on the order of about 20,000 cells, it is amazingly heterogeneous. It is likely that anatomical heterogeneity reflects an underlying functional heterogeneity. In this review, we examine the physiological responses of cells in the SCN to light stimuli that reset the phase of the circadian clock, highlighting where possible the spatial pattern of such responses. Increases in intracellular calcium are an important signal in response to light, and this increase triggers many biochemical cascades that mediate responses to light. Furthermore, only some cells in the SCN are actually endogenously rhythmic, and these cells likely do not receive strong direct input from the retina. Therefore, this review also considers how light information is conveyed from the retinorecipient cells to the endogenously rhythmic cells that track circadian phase. A number of neuropeptides, including vasoactive intestinal polypeptide, gastrin-releasing peptide and substance P, may be particularly important in relaying such signals, but other neurochemicals such as GABA and nitric oxide may participate as well. A thorough understanding of the intracellular and intercellular responses to light, as well as the spatial arrangements of such responses may help identify important pharmacological targets for therapeutic interventions to treat sleep and circadian disorders.

Serotonergic potentiation of photic phase shifts: examination of receptor contributions and early biochemical/molecular events

The 5-HT mixed agonist/antagonist 1-(2-methoxyphenyl)4-[4-(phthalimido)butyl]-piperazine hydrobromide (NAN-190) has been shown to greatly potentiate photic phase shifts in hamsters. The mechanism of this potentiation has yet to be determined. NAN-190 is believed to act primarily through the 5-HT(1A) receptor, but also binds to several other receptors, making it uncertain as to which receptor underlies its potentiation of photic phase shifts. Also uncertain are the intracellular changes in the suprachiasmatic nucleus (SCN) which are associated with such enhanced phase shifting. Here we examine the role of the 5-HT(1A) receptor as well as the physiological underpinnings, in terms of both gene expression and biochemical activation, in the behavioral responses to photic stimuli following pretreatment with NAN-190. Administration of NAN-190 to wildtype mice significantly potentiated late subjective night photic phase shifts, while mice lacking the 5-HT(1A) receptor (knockouts) exhibited an attenuated behavioral response to light when pretreated with NAN-190. In wildtype mice, the protein product of the immediate-early gene c-fos, induced following photic stimulation, was found to be significantly decreased with NAN-190 pretreatment. Similarly, the levels of phosphorylated CREB protein, involved in a biochemical pathway leading to gene transcription, were also attenuated by NAN-190 in the wildtype mice. However, activation of the extracellular signal-regulated kinase I/II (ERK) pathway in wildtype mice, following the light pulse, was not affected by NAN-190 pretreatment, nor was the expression of the circadian clock components Period1 and Period2. These findings suggest that the 5-HT(1A) receptor plays a critical role in the potentiation effect observed with NAN-190, and that NAN-190 may potentiate photic phase shifts at least partly by down-regulating the activity of some (but not all) genes and biochemical pathways involved in coupling the light signal to the output of the circadian clock.

Investigating the role of substance P in photic responses of the circadian system: individual and combined actions with gastrin-releasing peptide

The suprachiasmatic nucleus (SCN) contains the master mammalian circadian pacemaker. It is comprised of several phenotypically distinct cell groups, some of which are situated in the weakly rhythmic retinoresponsive ventrolateral region while others are found in the rhythmic, non-retinoresponsive dorsomedial region. The mechanism by which retinorecipient cells convey photic information to the dorsomedial clock cells is unclear. The ventrolateral SCN core contains a variety of cell phenotypes. Two neuropeptides, namely substance P (SP) and gastrin-releasing peptide (GRP) extensively colocalize with calbindin D28K, a marker for SCN cells that are strongly light-responsive. Previous studies have implicated these neuropeptides in photic phase shifting of the circadian system. The present study examines how these peptides interact to regulate photic responses of the circadian system. It was observed that 55.5 +/- 9.1% of SP cells colocalized GRP. SP did not enhance GRP-induced phase shifts in the early-subjective night, while it significantly attenuated GRP-induced phase shifts during the late-subjective night. SP induced significant phase shifts that did not resemble light in the early-subjective night, but was not necessary for light-induced phase shifts and Fos expression at this time. SP induced significant Fos expression only in the late subjective night. SP may not be a necessary component in the pathway(s) involved in photic phase shifting during the early-subjective night, but may modulate phase shifts during the late-subjective night. Distinct biochemical mechanisms that underlie behavioral phase shifts may account for the differences observed in the early- vs. late-subjective night.

Assessment of salivary human herpesvirus-6 and immunoglobulin a levels in nurses working shifts

PURPOSE

The purpose of the present study was to assess whether salivary human herpesvirus (HHV)-6 acted as a new sensitive stress marker, providing a reliable indicator of stress among shift work nurses. Salivary HHV-6, immunoglobulin (Ig) A and mood states were compared among nurses who worked day shifts only and nurses who worked different numbers of night shifts.

METHODS

Participants included 56 female nurses working in Japanese general hospitals. The 56 subjects were categorized into three groups: Group A (n = 7), which consisted of nurses who only worked day shifts; group B (n = 29), which consisted of nurses working shifts with £8 night shifts per month; and group C (n = 20), which consisted of nurses working shifts with (3) 9 night shifts per month. Mood was assessed using the Profile of Mood States Short Form Japanese version (POMS-SFJ). Salivary biomarker levels and mood were compared among the three groups.

RESULTS

Although the salivary HHV-6 level was significantly higher in group C than in group A (p < .05), salivary IgA and mood levels were not significantly different among the three groups.

CONCLUSION

Salivary HHV-6 level may be a more sensitive stress marker than salivary IgA or mood for assessing chronic fatigue in nurses working shifts. Improvement to shift assignments using assessment by salivary HHV-6 is required.