There is increasing evidence that shift work, an occupational exposure affecting about one-fourth of the working population, increases the risk of major chronic disease outcomes, such as cardiovascular disease and cancer.1–4 Currently, there is an open discussion on whether shift work should be included in national lists of occupational hazards for compensation purposes. Denmark was the first (and to date only) country to consider breast cancer an occupational disease in shift workers, and to compensate women with over 20 years of night work who developed breast cancer. Chronic disease risk reduction and prevention in shift workers is an emerging field, which points to the need for more intervention studies. Whether and how companies or governments translate existing evidence into real-world policy or preventive actions currently remains largely unknown.

The study by Hall et al5 is a unique effort and first step to investigate the extent to which companies from across occupational sectors in the Canadian province of British Columbia implement programmes with potential health impact for their employees. In this exploratory survey the authors describe a number of organisational factors that are associated with three key shift work practices: long working hours (≥12 hours), shift work educational materials/training for the employees and company night-time light policies. Their study showed that about two-thirds of all participating companies provided at least one policy, while the remaining one-third provided none. Larger companies were more likely to provide educational materials, although it is unknown if these materials reached their employees and if their use had any effect. As expected, company size and type of sector were associated with long shifts, while companies with a history of non-day accidents were more likely to use night-time lighting policies. Half of the organisations reported that their concern for employee health influenced shift work scheduling. However, current attempts of companies to help their shift workers cope and remain healthy seem of limited range and underline the need for action. Moving forward, shift workers may also benefit from enrolment into health monitoring and screening programmes. Such programmes may in addition help assess the impact of any implemented practices on circadian adaptation, sleep and health and allow the development of tailored interventions.

Shift work intervention research is a new and evolving field with many gaps and needs novel approaches. More workplace interventions assessing health-related outcomes among night shift workers are needed.6 Laboratory-based shift work simulations are useful but have limited ability to extrapolate findings to real-life shift workers. Often due to their short follow-up time, studies have focused on sleep, fatigue, well-being and other more immediate outcomes, which may be important for occupational safety and attractive to the employer, but perhaps not of greatest relevance for chronic disease prevention. Shift work schedules are complex—remarkably, Hall et al reported over 400 distinct shift schedules among 88 participating companies—and results are often difficult to compare across studies, making it hard to decide which intervention would best be suited to improve shift workers’ short-term and/or long-term health. Behavioural interventions targeting lifestyle changes appear to improve cardiometabolic health in some studies, and are a promising area for further investigation.6 Also, shift workers may require specific dietary counselling: studies have shown that although total energy intake may not differ between shift workers, meal timing and eating at the wrong time can still enhance circadian disruption.7 Further, shift work interventions at the work site (eg, regulating light at night) may be complemented by workers’ preventive behaviour outside of work hours (eg, the use of goggles to prevent light exposure during commuting time after a night shift). Therefore, in addition to organisational characteristics, a number of individual characteristics that relate to shift work tolerance are important for personalised prevention.8 These comprise chronotype9 and genetic phenotypes10 and could potentially be integrated into future occupational screening programmes targeting individual disease risk factors. Finally, with the increasing use of smart phones it has been possible to use mobile applications for disease prevention. In a recent study, airline company employees who received personalised advice through their mobile application coped better with irregular flight schedules and circadian disruption compared to their colleagues who only had access to the company's online educational material.11 Future shift-work interventions may benefit from custom-made mobile applications.

It is clear that action needs to be taken at multiple levels. First, there is a need for larger workplace interventions with longer follow-up periods and a focus on chronic disease prevention among shift workers. Second, future interventions should consider workers’ characteristics in addition to organisational features. Finally, evidence-based recommendations need to be translated into health prevention strategies implemented by companies, but workers will also benefit from enrolment into health monitoring and screening programmes. With more studies like the one by Hall et al, such actions are likely to become more common place in the everyday life of shift workers, and will ultimately contribute to a reduced disease burden in shift workers.