COLUMBUS, Ohio - Job satisfaction in your late 20s and 30s has a link to overall health in your early 40s, according to a new nationwide study.

While job satisfaction had some impact on physical health, its effect was particularly strong for mental health, researchers found.

Those less than happy with their work early in their careers said they were more depressed and worried and had more trouble sleeping.

And the direction of your job satisfaction - whether it is getting better or worse in your early career - has an influence on your later health, the study showed.

The good news is that people whose job satisfaction started low but got better over the course of their early career didn't have the health problems associated with consistently low or declining satisfaction.

"We found that there is a cumulative effect of job satisfaction on health that appears as early as your 40s," said Jonathan Dirlam, lead author of the study and a doctoral student in sociology at The Ohio State University.

Dirlam conducted the study with Hui Zheng, associate professor of sociology at Ohio State. They presented their research Aug. 22 in Seattle at the annual meeting of the American Sociological Association.

Zheng said the results showed the importance that early jobs have on people's lives.

"You don't have to be near the end of your career to see the health impact of job satisfaction, particularly on your mental health," Zheng said.

The researchers used data from 6,432 Americans who participated in the National Longitudinal Survey of Youth 1979, which followed adults who were between the ages of 14 and 22 when the survey began in 1979.

The NLSY79 is conducted by Ohio State's Center for Human Resource Research for the U.S. Bureau of Labor Statistics.

For this study, the researchers examined job satisfaction trajectories for people from age 25 to 39. These participants then reported a variety of health measures after they turned 40.

Participants rated how much they liked their jobs from 1 (dislike very much) to 4 (like very much).

The researchers put participants in four groups: consistently low and consistently high job satisfaction, those whose satisfaction started high but was trending down and those who started low but were trending higher.

The average score of those classified as the low group was nearly 3 (indicating they liked their job "fairly well"), Dirlam noted. But there was a lot of variance in that group, meaning that it included all the people who said they disliked their jobs somewhat or very much.

About 45 percent of participants had consistently low job satisfaction, while another 23 percent had levels that were trending downward through their early career.

About 15 percent of people were consistently happy at their jobs (nearly 4 on the scale) and about 17 percent were trending upward.

Using those who were consistently happy as the reference, the researchers compared how the health of the other three groups compared.

Mental health was most affected by people's feelings about their jobs.

People who were in the low job satisfaction group throughout their early careers scored worse on all five of the mental health measures studied, study results showed.

They reported higher levels of depression, sleep problems and excessive worry. They were also more likely to have been diagnosed with emotional problems and scored lower on a test of overall mental health.

Those whose job satisfaction started out higher but declined through their early career were more likely than those with consistently high satisfaction to have frequent trouble sleeping and excessive worry, and had lower scores for overall mental health. But they didn't see an impact on depression scores or their probability of being diagnosed with emotional problems.

Those whose scores went up through the early career years did not see any comparative health problems.

The physical health of those who were unhappy with their jobs wasn't impacted as much as mental health. Those who were in the low satisfaction group and those who were trending downwards reported poorer overall health and more problems like back pain and frequent colds compared to the high satisfaction group. But they weren't different in physical functioning and in doctor-diagnosed health problems such as diabetes and cancer.

As was true for mental health, no effects were seen on physical health for those trending upward.

Zheng said it is important to remember that participants were studied when they were only in their 40s.

"The higher levels of mental health problems for those with low job satisfaction may be a precursor to future physical problems," Zheng said.

"Increased anxiety and depression could lead to cardiovascular or other health problems that won't show up until they are older."

Dirlam noted that the study ended before the Great Recession.

"The recession almost certainly increased job insecurity and dissatisfaction, and that could have resulted in more negative health effects," he said.