Factors influencing health of workers and tolerance to shift work

Shift and night work are a well recognized risk factors for health and well-being, but the outcomes are not always in agreement and sometimes contradictory, due to both different working and living conditions of the groups examined, and to different approaches and methods used. Moreover, variations in historical and epidemiological relevance of the disorders, health perception and surveillance, as well as combined effects with other individual and social risk factors make the problem multifaceted and difficult to interpret properly. Consequently, also tolerance to shift and night work is a complex phenomenon, related to several aspects pertaining to different domains, dealing with personal characteristics and coping strategies, family and social conditions, working situations and, particularly, working hours organization. The result of their interactions depends not only on the specific load of each factor, but also on their temporal occurrence and duration in the worker's life. Thus, it is necessary to clarify as much as possible the interactions among individual aspects, social conditions and work organization, for an effective promotion of shift workers' health and well-being. The aim of the paper is to review the main factors that can intervene on such aspects trying to present 'lights and shadows' on this context.