Study Finds Lack of Control Is Key Factor in Jobs Endangering Hearts

NEW YORK — Men whose jobs combine high psychological demands with little control over their work face two to three times the risk of heart attack that other male workers do, a new study suggests.

Cooks, waiters, computer operators, gas station attendants and some assembly line workers were among the high-risk jobs found in the analysis of nearly 5,000 men.

But employers may be able to redesign high-risk jobs to lower heart attack risk and improve productivity, said Robert Karasek, associate professor in the industrial and systems engineering department at USC.

Karasek reported the study’s findings in the August issue of the American Journal of Public Health, along with co-authors from Sweden, the State University of New York at Stony Brook, Cornell University Medical School and Columbia University.

Focus on Strain

The study focused on job strain, which results from having too little control over one’s work to deal satisfactorily with its psychological demands. Those demands included having to work quickly and facing heavy workloads.

Executive and professional jobs were not considered high-strain because they include a lot of control, Karasek said.

The study was based on heart attacks reported by men in two federal surveys. Too few women with heart attacks appeared in those surveys for a meaningful analysis of them, Karasek said.

One federal study, the Health Examination Survey in 1960-61, found 39 heart attacks among 2,409 employed men. The other, the Health and Nutrition Examination Survey, done from 1971 to 1975, counted 30 heart attacks among 2,424 employed men.

Job Conditions Studied

To assess job characteristics for all 4,838 men, researchers used federal studies of the conditions faced by workers on various jobs. Measurements for job traits such as control over the work were computed for 221 occupations.

Then those measurements were adjusted for each worker, based on his age, race, education, geographic region and whether he was self-employed or worked in a city.

The study gave two sets of findings, one from each of the large federal surveys:

--Men whose jobs put them in the top 20% for job strain had 2.48 times and 3.28 times the risk of heart attack of the other workers. The comparison took into account their age, which Karasek said was the most important influence on heart attack risk, but ignored other risk factors like smoking.

--Men in the top 10% for job strain ran 3.8 and 4.79 times the heart attack risk of men in the lowest 10%. Jobs in the top 10% included cashiers and waiters, while those in the bottom 10% included foresters, natural scientists and civil engineers.

This comparison took into account a list of heart attack risk factors: age, race, cigarette use, education, blood pressure and cholesterol levels.

--Job strain accounted for between one-fourth and one-third of heart attacks in the two surveys. This analysis accounted only for age, but Karasek said the results were similar when the other risk factors were also considered.

The study does not prove that job strain raises the risk of heart attacks, Karasek said, but the idea is supported by other research.

In this study, researchers did not know if workers were in their reported jobs when the heart attack occurred. But it is unlikely that a worker would have a heart attack in a low-strain job and later move into a high-strain one, Karasek said.

Giving workers more control has long been advocated as a means of increasing productivity, he said. It might also reduce job strain, along with letting workers use under-utilized skills and turning their jobs into platforms for learning new skills, he said.