Nursing staff take more sick days per year than most other public sector workers, research reveals.
Figures from the Healthcare Commission, based on 135,000 staff on 6,000 hospital wards, show on average staff have 16.8 days in every 12 months.
This means they take more time off than prison staff who took an average of 14.7 days off through ill health in 2004.
This compares with 11.3 days a year across seven other public sector groups, including police and teachers. Sick leave among ward staff costs about £470m a year.
Anna Walker, chief executive of the commission, said the causes were unclear, but factors such as stress, job satisfaction, workload and the physical nature of the job all may be part of the picture.
The Department of Health said reducing stress and sickness among staff was an important objective for NHS trusts.
The report also found that 13.2% of ward staffing expenditure was spent on bank and agency staff in the first quarter of 2004/05, a similar figure to 2000.