Sleep disturbances increase the risk of work disability and may slow the return to work process. This is especially true in cases where work disability is due to mental disorders or musculoskeletal diseases. These results come from a recent study conducted by the Finnish Institute of Occupational Health in collaboration with the universities of Turku and London.

The research is being conducted as part of two major research projects on social capital in the workplace (Kunta10) and on well-being in the hospital workplace. The follow-up study is part of the Academy of Finland Research Programme on The Future of Work and Well-being (WORK) and the Responding to Public Health Challenges Research Programme (SALVE).

Sleep disturbances include difficulties initiating sleep, intermittent and non-restorative sleep, and waking up too early. The occurrence of these disturbances was studied in 56,732 public sector employees in Finland. During the three-year follow-up, 7 per cent of them were incapacitated for work. Data on work disability and sickness absences lasting 90 days or longer, disability pensions and deaths were obtained from national registers. The associations of sleep disturbances with returning to work were studied in employees who were on long-term sickness leave or retired on disability pension.

Just over one-fifth or 22 per cent of the employees studied reported sleep disturbances on at least five nights a week. A further 26 per cent reported sleep disturbances on 2𔃂 nights a week. In the former group, the risk of work disability for any reason was one and a half times greater than in employees who reported sleep disturbances once a week or less often.

The risk of work disability due to mental health problems or musculoskeletal disorders was elevated both in employees reporting mild and in those with severe sleep disturbances. Severe sleep disturbances were also associated with work disability due to cardiovascular diseases, neurological diseases and external reasons such as accidents.

Sixty per cent of the employees who were incapacitated returned to work within two years. The risk of a delayed return to work was higher among those whose work disability was due to musculoskeletal disorders. Among men whose incapacity was due to mental health diseases, both mild and severe sleep disturbances predicted a slower return to work.

The results of the study have been published in the latest issue of the Sleep journal, see www.journalsleep.org/ViewAbstract.aspx?pid=27917.