Compared to individuals who work during the day, shift workers are at higher risk of a range of metabolic disorders and diseases (eg, obesity, cardiovascular disease, peptic ulcers, gastrointestinal problems, failure to control blood sugar levels, and metabolic syndrome). At least some of these complaints may be linked to the quality of the diet and irregular timing of eating, however other factors that affect metabolism are likely to play a part, including psychosocial stress, disrupted circadian rhythms, sleep debt, physical inactivity, and insufficient time for rest and revitalization. In this overview, we examine studies on food and nutrition among shift workers [ie, dietary assessment (designs, methods, variables) and the factors that might influence eating habits and metabolic parameters]. The discussion focuses on the quality of existing dietary assessment data, nutritional status parameters (particularly in obesity), the effect of circadian disruptions, and the possible implications for performance at work. We conclude with some dietary guidelines as a basis for managing the nutrition of shift workers.

Nijp HH, Beckers DGJ, Geurts SAE, Tucker P, Kompier MAJ. Systematic review on the association between employee worktime control and work-non-work balance, health and well-being, and job-related outcomes. Scand J Work Environ Health. 2012;38(4):299-313. doi:10.5271/sjweh.3307 Objectives The aim of this review was to assess systematically the empirical evidence for associations between employee worktime control (WTC) and work-non-work balance, health/well-being, and job-related outcomes (eg, job satisfaction, job performance).Method A systematic search of empirical studies published between 1995-2011 resulted in 63 relevant papers from 53 studies. Five different categories of WTC measurements were distinguished (global WTC, multidimensional WTC, flextime, leave control, and "other subdimensions of WTC"). For each WTC category, we examined the strength of evidence for an association with (i) work-non-work balance, (ii) health/well-being, and (iii) job-related outcomes. We distinguished between cross-sectional, longitudinal, and intervention studies. Evidence strength was assessed based on the number of studies and their convergence in terms of study findings.Results (Moderately) strong cross-sectional evidence was found for positive associations between global WTC and both work-non-work balance and job-related outcomes, whereas no consistent evidence was found regarding health/well-being. Intervention studies on global WTC found moderately strong evidence for a positive causal association with work-non-work balance and no or insufficient evidence for health/well-being and job-related outcomes. Limited to moderately strong cross-sectional evidence was found for positive associations between multidimensional WTC and our outcome categories. Moderately strong cross-sectional evidence was found for positive associations between flextime and all outcome categories. The lack of intervention or longitudinal studies restricts clear causal inferences. ConclusionsThis review has shown that there are theoretical and empirical reasons to view WTC as a promising tool for the maintenance of employees' work-non-work balance, health and well-being, and job-related outcomes. At the same time, however, the current state of evidence allows only very limited causal inferences to be made regarding the impact of enhanced WTC.Key terms job motivation; job performance; stress; work-family conflict; work scheduling; worktime flexibility.1 Behavioural Science Institute, Radboud University Nijmegen, The Netherlands. 2 Stress Research Institute, Stockholm University, Sweden. 3 Psychology Department, Swansea University, United Kingdom.Correspondence to: Hylco Nijp, Behavioural Science Institute, Radboud University Nijmegen, PO Box 9104, 6500 HE, Nijmegen, the Netherlands. [E-mail: h.nijp@psych.ru.nl] During the past decades, organizations increasingly emphasized work-related flexibility in their organizational practices (1). One type of flexibility that has become more common is "temporal flexibility", ie, flexibility regarding working ti...

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Objectives-Shiftwork is now a major feature of working life across a broad range of industries. The features of the shift systems operated can impact on the wellbeing, performance, and sleep of shiftworkers. This paper reviews the current state of knowledge on one major characteristic of shift rotas-namely, shift duration. Evidence comparing the relative eVects of eight hour and 12 hour shifts on fatigue and job performance, safety, sleep, and physical and psychological health are considered. At the organisational level, factors such as the mode of system implementation, attitudes towards shift rotas, sickness absence and turnover, overtime, and moonlighting are discussed. Methods-Manual and electronic searches of the shiftwork research literature were conducted to obtain information on comparisons between eight hour and 12 hour shifts. Results-The research findings are largely equivocal. The bulk of the evidence suggests few diVerences between eight and 12 hour shifts in the way they aVect people. There may even be advantages to 12 hour shifts in terms of lower stress levels, better physical and psychological wellbeing, improved durations and quality of oV duty sleep as well as improvements in family relations. On the negative side, the main concerns are fatigue and safety. It is noted that a 12 hour shift does not equate with being active for only 12 hours. Conclusions-There can be considerable extension of the person's time awake either side of the shift. However, the eVects of longer term exposure to extended work days have been relatively uncharted in any systematic way. Longitudinal comparative research into the chronic impact of the compressed working week is needed. (Occup Environ Med 1998;55:217-229) Keywords: shift duration; health; sleep; 12 hour shifts In response to economic, technological, and social pressures a 24 hour organisation of the workplace is now common. This requires the workforce to accept and become adapted to many diVerent forms of shiftwork schedule. However, the adverse eVects of shiftworking are well chronicled.1-3 They include biological disruption to physiological processes, including the sleep-wake cycle 4 ; the impairment of physical health and psychological wellbeing 3 5 ; problems with alertness, performance, and safety, 6 7 and lastly, interference with social and domestic life. 8 9 The extent to which shiftwork aVects the individual person depends largely on the job being done, characteristics of the individual, the organisational and social environments, and features of the shift system. This potential impairment to functioning exists because daily rhythms in human physiology, hormone concentrations, biochemistry, and behaviour have become entrained to the most reliable and predictable cyclic changes in the physical and social environments. Under shiftworking conditions, and especially when required to work at night, the components of this system of circadian rhythms are regularly disrupted as a result of having to alter the activity-rest cycle.Many thousands of...

Shift work chronically impairs cognition, with potentially important safety consequences not only for the individuals concerned, but also for society.

This brief paper reviews the available published literature on shiftwork and safety that allows the relative risk of "accidents" or injuries associated with specific features of shift systems to be estimated. Three main trends in risk are discussed, namely that (i) risk is higher on the night shift, and to a lesser extent the afternoon shift, than on the morning shift, (ii) risk increases over a span of shifts, especially so if they are night shifts, and (iii) risk increases with increasing shift length over eight hours. We discuss that some of these trends are not entirely consistent with predictions derived from considerations of the circadian variations in sleep propensity or rated sleepiness, and consider factors relating to sleep that may underlie the observed trends in risk. Finally, the practical implications of the trends in risk for the design of safer shift systems are discussed.

Modern societies are dependent on people working shifts. This study systematically reviews literature on the consequences of quick returns (11.0 hours or less between two shifts). Quick returns have detrimental effects on acute health problems. However, the evidence regarding effects on chronic health is inconclusive.

Potential effects of shift work on health are probably related to the misalignment between the light-dark cycle and the human activity-rest cycle. Light exposure at night mediates these effects, including social misalignment and leads to an inversion of activity and rest, which, in turn, is linked to changes in behaviours. This article reviews the epidemiological evidence on the association between shift work and health, and possible mechanisms underlying this association. First, evidence from findings of the meta-analyses and systematic reviews published in the last 10 yr is presented. In addition, it reports the larger single-occupation studies and recent large population-based studies of the general workforce. Koch’s postulates were used to evaluate the evidence related to the development of disease as a result of exposure to shift work. Finally, we discussed limitations of the multiple pathways that link shift work with specific disorders and the methodological challenges facing shift work research. We concluded that the clearest indications of shift work being the cause of a disease are given when there is a substantial body of evidence from high quality field studies showing an association and there is good evidence from laboratory studies supporting a causal explanation of the link.