• Whether a person was employed at all, long working hours, shift work and the extent to which work conflicts with a person's family life.
• Social support and social opportunities, the 'organisational justice' (the perceived level of fairness in the workplace).
• How much control employees have over their work, the demands of the job and the availability of health insurance (considered vital in the US).
They then investigated how these stressors affect four outcomes.
The outcomes were:
• How a person rates their physical health
• How a person rates their mental health
• Whether they are more likely to be diagnosed with a medical condition by a doctor
• Whether they are more likely to die of an early death
The researchers presented their findings using odds ratios, showing how much an individual stressor was likely to raise the odds of a negative health outcome, such as an early death.
The study found that factors like being unemployed, having little control in a job or having no health insurance are all more likely to put a person in an early grave than being exposed to second-hand smoke.
Working long hours and having a job that heavily conflicts with family life also raised the risk of an early death more than second-hand smoke exposure, each increasing the odds of this by 20 per cent.
Having no health insurance, feeling that the workplace is unfair, having a demanding job carried a higher risk of being diagnosed with a disease by a doctor than second-hand smoke.
For example, feeling as though the workplace is unfair increases this risk by 50 per cent.
Doing shift work or being unemployed also carries a higher risk of being diagnosed with an illness than smoke exposure.
Writing in the study, the researchers said: "Our results suggest that many workplace conditions profoundly affect human health.
"In fact, the effect of workplace stress is about as large as that of second-hand tobacco smoke, an exposure that has generated much policy attention and efforts to prevent or remediate its effects."
"When you think about how much time individuals typically spend at work, it's not that surprising," Joel Goh, an assistant professor at Harvard Business School, and the study's co-author, told CNN.
He said many companies now have "wellness programmes" which include exercise and yoga classes at lunchtimes.
But the focus shouldn't solely be on the employee's actions, companies should also think about the effects managers have on their staff, he added.
"Wellness programs are great at doing what they're designed to do," he told the Boston Globe.
"But they're targeting [employee behaviour], not targeting the cause of stress.
"There are two sides of the equation and right now we focus on one side.
"We're trying to call attention to the other side, which is the effect of managerial practices."
- Daily Mail