Job loss is a possible trigger for heart attack, putting at risk older people and those with serious medical conditions such as high blood pressure and obesity, a new U.S. study said.

Published Monday by the Archives of Internal Medicine journal, the study commissioned by the National Institute of Aging said that losing employment at age 50 and above leads to sufficient stress development that leaves one susceptible to cardiac complications.

The 18-year study, which was supervised by Prof Matthew Dupre of Duke University, tracked the medical and employment history of volunteer respondents, who supplied information such as their health situation and job status.

The report noted that all the participants have admitted of employment issues, with about 70 per cent listing of at least one incident of job loss throughout the course of the study while another 10 per cent experienced four or more cases of employment severance.

Those interviewed also shared medical conditions and lifestyles that could influence their healthy disposition but according to Prof Dupre, volunteers that suffered heart attacks prior to the study's start were dropped from the final analysis.

By the end of the monitoring, 1061 heart attacks were recorded by researchers and it was determined that male and female were equally at risk by the parameters defined by the research.

However, it was observed too that the frequency of job loss seemed to heighten the risk of heart ailment, with those losing employment more than four times likely to deal with 60 per cent high risk of suffering heart attack.

The likelihood of going through the same dangerous condition is only 22 per cent for participants with only a single incident of losing job, the report said.

Albeit not measured by numbers, Prof Dupre said that the manner a person loses job is also a noteworthy factor, adding that being fired or laid off could prove too much for a person already nursing a fragile health situation.

The heavy reality of losing one's source of livelihood could act as the fuse for an already ticking health-bomb, the study suggested.

This position was supported by University of Michigan researcher Sarah Burgard, who was not part of the study.

"There probably are differences in consequences of job loss when it's voluntary or more or less expected," Ms Burgard told The Associated Press (AP).