Simply worrying about losing your job can cost you your health, a new investigation of data from two long-term studies finds.

Surprisingly, the effect is worse than actually losing your job, the research suggests.

"Based on how participants rated their own physical and mental health, we found that people who were persistently concerned about losing their jobs reported significantly worse overall health in both studies and were more depressed in one of the studies than those who had actually lost and regained their jobs recently," said Sarah Burgard, a sociologist at the University of Michigan.

"In fact, chronic job insecurity was a stronger predictor of poor health than either smoking or hypertension in one of the groups we studied," Burgard said.

One simple reason: the stress caused by insecurity. Other research has shown that stress can be deadly, leading to a range of poor health conditions that can shorten one's life.

Burgard and colleagues examined data from two nationally representative sample surveys of the U.S. population; each survey was based on two interviews with each of the study participants. One of the surveys was conducted between 1986 and 1989, the other between 1995 and 2005.

The results were announced today and published in the journal Social Science & Medicine.

"Dramatic changes in the U.S. labor market have weakened bonds between employers and employees and fueled perceptions of job insecurity," Burgard argues, citing other studies that support this contention. She admits, though, that the research into this claim could be more robust.

"We need more and better data on this," she told LiveScience.

Why would insecurity be worse for health than getting fired?

"Ongoing ambiguity about the future, inability to take action unless the feared event actually happens, and the lack of institutionalized supports associated with perceived insecurity are among them," she said.

The researchers controlled for other factors - race, marital status, neurotic tendencies, education and job characteristics - to make sure the apparent link between insecurity and health was not actually based on something else. For example, they ruled out the possibility that poor health was the cause of insecurity.

"When you consider that not only income but so many of the important benefits that give Americans some peace of mind-including health insurance and retirement benefits-are tied to employment for most people, it's understandable that persistent job insecurity is so stressful," Burgard said.

The work offers food for thought for employees, employers and policy makers during this time of high unemployment, the researchers note.

"Certainly job insecurity is nothing new, but the numbers experiencing persistent job insecurity could be considerably higher during this global recession, so these findings could apply much more broadly today than they did even a few years ago."

Burgard and her colleagues, James House at the University of Michigan and Jennie Brand at the University of California, were supported by the Robert Wood Johnson Foundation and the National Institute of Child Health and Human Development. They drew from the Americans' Changing Lives Study, supported in part by the National Institute on Aging, and from the Midlife in the United States Study, funded in part by the John D. and Catherine T. MacArthur Foundation.

If you're feeling good about your job's prospects, here's one more thing to stress about: Other research has shown that the stress of a tough job - long hours and high pressure to perform - can also ruin your health.

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