Like High Cholesterol, Overtime Work Boosts Heart Disease

April 5, 2011— -- For almost 30 years, Jim worked 11 hours a day as a Wall Street trader. Then a heart attack forced him into early retirement.

"You had to work long hours and there was no way around it," said Jim, who asked to be identified by his first name only. "If you're doing it, it's the lifestyle you selected."

Jim's stressful work day included long commutes to and from Manhattan. And even when he was home, work was on his mind.

"You can leave some of it behind, but you can't leave all of it," Jim said. "You're too wound up."

New research suggests Jim's workaholic lifestyle may have contributed his heart attack.

A study of 7,095 British civil service workers revealed that those who toiled 11 or more hours per day had a 67 percent higher risk of coronary heart disease than their 9-to-5 officemates.

"We knew there was an association between working long hours and coronary heart disease, but we were really surprised that it was such a strong predictor," said Mika Kivimaki, professor of epidemiology and public health at University College London and lead author of the study published in the Annals of Internal Medicine.

Currently a person's risk for heart disease is calculated based on age, gender, blood pressure, blood sugar, cholesterol and cigarette smoking. But adding work hours into the mix boosted the risk calculator's predictive value by 4.7 percent. That means that of the 1.2 million Americans who will have a heart attack this year, 56,000 might have a better idea of their risk if doctors asked about their work hours, according to Kivimaki.

Coronary heart disease is caused by a build-up of fatty plaques (atherosclerosis) inside the blood vessels that feed the heart. It's the leading cause of death in the United States, according to the American Heart Association.

"What we cannot say is that the long hours cause coronary heart disease," Kivimaki said. "It could be other things related to working long hours."

It could be, for example, that people who work long hours exercise less or eat more irregularly. It could also be that workaholics get less sleep and are more stressed.

"If you work very long hours for a long time it clearly seems to be associated with an increased risk of sleep problems and depression and other adverse effects that can also affect physical heath," Kivimaki said.

The study adds to growing evidence that psychosocial factors, such as work stress, depression and lack of social support, are important contributors to heart disease risk.

"It's yet another weight in the balance that we really do need to expand our assessment of risk beyond the usual suspects of smoking, cholesterol and high blood pressure," said Dr. Redford Williams, professor of medicine and director of the Behavioral Medicine Research Center at Duke University, in Durham, N.C.