Researchers have informed that a study of British civil servants found overtime-induced work stress may contribute to a substantial proportion of cardiovascular disease.

Published online ahead of print in the European Heart Journal, the study also found that compared with government employees who didn't work overtime, workers who added 3 or more hours to the workweek -- but not 1 to 2 hours-- had a 60 percent higher risk of as death due to heart disease, non-fatal heart attacks and angina.

The study involved 4,262 men and 1,752 women, ages 39-61, whose normal workday was 7 hours, were tracked until 2002-04, with an average 11.2 years of follow-up.

There were, during the study period, 369 cases of fatal coronary heart disease, non-fatal heart attacks or angina.

The finding was independent of other risk factors such as smoking, being overweight or having high cholesterol, Marianna Virtanen, an epidemiologist at the Finnish Institute of Occupational Health, and colleagues in England and France said.

Virtanen further said, "Our findings suggest a link between working long hours and increased coronary heart disease risk but more research is needed before we can be confident that overtime work would cause coronary heart disease." (With Inputs from Agencies)