There is a life-expectancy gap in America. One report, using actuarial data, found that white-collar workers live longer than blue-collar workers. Another study confirmed this, finding that high-income workers have longer life expectancy than low-income ones. Does the the kind of job someone has contribute to, or detract from, their longevity? And, if so, how?

A new study that looks at the effects of workplace stress on the human lifespan offers a possible explanation. Working from the premise that better-paid jobs are associated with better health outcomes, a team of researchers from Harvard Business School and Stanford University used data from the General Social Survey and the American Community Survey to measure harmful workplace conditions’ influence on disparities in life expectancy. To calculate the stressfulness of a given workplace, they considered the probability of getting laid off, the length of working hours, the option to have employer-provided health insurance, and several other proxies.

The study found that stressful workplaces did make it more likely for workers to die earlier, although the size of the effect differed based on race and educational background. The effect was smaller for well-educated people: Five to 10 percent of their mortality was associated with exposure to these stressful workplace factors, whereas for those with less schooling the effect was between 12 and 19 percent.