Working long hours can greatly increase the risk of suffering injury or illness, a study says.

Workers who do overtime were 61% more likely to become hurt or ill, once factors such as age and gender were taken into account.

And working more than 12 hours a day raised the risk by more than a third, the University of Massachusetts found.

Report co-author Allard Dembe said risk was not necessarily associated with how hazardous（有危险的） the job was.

"The results of this study suggest that jobs with long working hours are not more risky merely because they are concentrated in inherently（内在地） hazardous industries or occupations."

And he said the findings, published in the Occupational and Environmental Health journal, supported initiative such as the 48-hour European Working Time Directive to cut the number of working hours.

From the records, researchers found 5,139 work-related injuries and illnesses, ranging from stress to cuts, burns and muscle injuries.

More than half of these injuries and illnesses occurred in jobs with extended working hours or overtime.

The researchers concluded that the more hours worked, the greater the risk of injury.

But they did not find that lengthy commutes to and from work had any impact on illness and injury.

In the UK 14% of the working population--3.6m--work more than 48 hours a week.