London, August 21:

Long working hours increase your chances of illness and injury, irrespective of what job you do, an American study said. Routinely working at least 12 hours a day posed a 37 per cent extra risk over those working fewer hours, while a 60-hour week was associated with a 23 per cent increased risk, according to its authors. They studied the responses of nearly 11,000 Americans to annual surveys of employment history, work schedules and sick leave betwen 1987 and 2000. Lengthy commuting to work had no effect on the accident or illness rate, and the impact of overtime and the long hours culture did not depend on how hazardous the job was, the researchers at the University of Massachussets medical school reported. They said their findings were consistent with a hypothesis that working longer hours indirectly caused workplace accidents through fatigue and stress, although they did not investigate the specific ways in which this might have happened.

A number of studies have suggested an increased risk of occupational injuries by specific workers, including builders, nurses, vets and other healthcare professionals, long-distance lorry drivers, miners, firefighters and nuclear power plant workers. The study, reported in the journal Occupational and Environmental Medicine, draws on more than 110,000 work records and reports of 5,139 work-related injuries and illnesses. More than half of those occurred in jobs with extended hours or overtime. In the US, up to a third of overtime worked is compulsory. The researchers said people who worked overtime were 61 per cent more likely to suffer occupational injuries and illnesses than those who did not. During the 1990s, there was a decline in overall work-related illness and injury. This might not only be down to safer working or a transfer from manufacturing to service jobs.

The cohort of people in the study were aged 23 to 31 at the start and 35-43 in 2000. Younger workers generally have a higher incidence of accidents than older ones. “This study supports initiatives of the EU and other governments to regulate the length of working schedules,” the authors said. People working overtime needed protection, by periodic safety inspections of workplaces, for instance. But changes in work patterns might be needed as well — rest breaks, recruitment of more people to do fewer hours and by redesigning schedules to avoid the need for overtime. Changes in individual behaviour — plenty of sleep, good nutrition, daily exercise and an avoidance of drugs and alcohol — might help too, although further research was needed in these areas.