Working hours, health, well-being and participation in working life : Current knowledge and recommendations for health and safety

The characteristics and flexibility of working hours are changing rapidly in all the Nordic countries. Working hours are becoming more boundaryless among the higher socioeconomic groups, whereas every fifth employee still works shifts. Nordic countries share similar working life structures and bases for working hour regulations. The overall aim of the NordForsk-funded ‘Working hours, Health, Well-being and Participation in Working life’ project (WOW, 2015–2021) was to develop evidencebased models and solutions related to working hours to support health and work participation in the Nordic countries. The specific aims of WOW were to investigate the societal and socio-economical differences and trends of Nordic working hour patterns using representative national and European data to identify policy-relevant trends and vulnerable groups for targeted interventions. Secondly, we studied the effects of shift work and working time autonomy on health, incident chronic diseases, work-life balance and work participation using five prospective cohort studies in Denmark, Finland, Norway and Sweden. Finally, ten intervention and two diary-based studies were carried out to create and test different organizational and individual level countermeasures related to working hours in shift work, boundaryless expert work, and safety-critical 24/7 industries to generate criteria and tools to improve health, well-being and work participation. Through its high number of cohort and intervention studies, to date, WOW has produced over 100 scientific publications in international journals. The main findings indicate that compared to other European countries, Nordic countries have shorter average working hours and more working time control. However, they also have many differences. Earlier research has shown that working over 55 hours per week is associated with an increased risk of chronic health problems. These results were not replicated in Scandinavia in terms of chronic health and occupational injuries, possibly due to the lower number of people working such long weekly hours. However, reduced working hours, namely six-hour workdays or 30-hour weeks, with retained salary, has shown beneficial effects on subjective health, sleep and well-being. The WOW studies have lent new support to the associations between exposure to night shift work and several acute and chronic conditions such as the increased risk of fatigue and insomnia, occupational injuries, rheumatoid arthritis, type-2 diabetes, hypertension, miscarriage, and hypertension and preeclampsia during pregnancy, as well as short and long sickness absence and disability pensions. We have found mixed results regarding the association between night shift work and breast cancer, mortality and dementia, and no support for an association between night shift work and prostate cancer. The cohort and diary studies on working time control showed beneficial associations with work-life balance, mental and physical health, and sickness absence. The intervention studies showed that self-rostering, the use of participative shift scheduling among hospital employees, and the use of stress therapy among managers had positive effects on work-life balance and work participation. The use of rapidly forward-rotating 12-hour shift systems in industry showed beneficial effects on perceived health compared to 8-hour shift systems. In 24/7 safety-critical industries, the use of fatigue risk management systems was a promising way to reduce fatigue, in addition to the use of some working hour regulations or single countermeasures such as the use of training or nap breaks. In shift work, the appropriateness of bright light therapies likely depends on the number of consecutive night shifts, making this strategy difficult in quickly rotating shift work, which is common in the Nordic countries. Shift workers with insomnia may benefit from different nonpharmacological insomnia interventions performed by occupational health services. The WOW project has produced and updated cross-national working time recommendations, especially in terms of night shift work, flexible working hours and individual coping with unsocial working hours