A new study from the Centers for Disease Control and Prevention shows that certain jobs—particularly blue-collar jobs or work in the service industry—can increase your risk of heart attack and stroke.

For every U.S. worker, there is a different set of workplace hazards and sources of stress. Construction workers are often exposed to dangerous chemicals, car exhaust, dust, secondhand smoke, and high levels of noise. Waiters and waitresses must deal with high levels of stress, constant movement, and the hazard of slippery floors or clutter.

“There is increasing interest in workplace-based disease prevention, health promotion and wellness programs as a means of improving health,” said Dr. Gregg Fonarow, a professor of cardiology at the University of California, Los Angeles.

Of all workers surveyed under age 55, 1.9 percent had a history of heart disease or stroke. Many of these cases stem from pre-existing factors, such as high cholesterol or blood pressure, but they can be exacerbated by workplace stress.

“It’s probably a combination of personal and work factors,” said lead researcher Dr. Sara Luckhaupt of the National Institute for Occupational Safety and Health. “Don’t forget the job factors,” Luckhaupt said. “The noise, the air pollution and job stress could be contributing to the personal risk factors, like difficulty quitting smoking.”

However, unemployed workers are not safe from occupational stress, according to the study. The rate of stroke and heart attack among unemployed workers was 2.5 percent.

“It may be that the stress of unemployment and the lack of access to health care may be contributing to their health problems,” she said.

But the cause-and-effect relationship is hard to prove for unemployed workers. At this point, it is impossible to tell whether these workers have health problems because of unemployment (and the resulting lack of access to health care) or if they are unemployed because of ongoing health problems.

“Health professionals, employers and workers should take proactive steps to improve their heart health, implement and take advantage of comprehensive workplace wellness programs and better utilize effective interventions to prevent heart disease and stroke,” Dr. Fonarow said.

Another factor that can contribute to increased health risk is a worker’s shift schedule. Nearly 15 million Americans work full time on evening shift, night shift, rotating shifts, or other irregular schedules, according to the Bureau of Labor Statistics. Work hours in the U.S. exceed Japan and most of western Europe, and this high-pressure, high-productivity environment can be dangerous for workers’ health. Extended shifts have been linked to car accidents, high blood pressure, and psychological problems down the road.

Heart disease and stroke, the main focus of the study, continue to present a serious danger to U.S. workers. Heart disease and stroke, the No. 1 and No. 3 causes of death, respectively, account for one-third of all U.S. deaths.

The study was published in the August 1 issue of Morbidity and Mortality Weekly Report using data from the 2008-2012 National Health Interview Survey.