Stress at work raises the risk of heart disease for women under 50, a Danish study suggests.
In industrialised countries, cardiovascular disease (CVD), including ischaemic heart disease (IHD), is the leading cause of death and affects as many women as men. In Denmark, more than one third of all deaths among women are caused by CVD. Many risk factors are similar for men and women, but gender differences are known to exist.
During the last decades, several studies have examined the impact of work-related psychosocial factors on IHD. A review from 2000 of cohort and case-control studies of men concluded that a combination of excessive psychological demands and lack of control (job strain) increases the risk of IHD. More recent reviews have found the evidence inconclusive, and only a few studies on women are available.
A Danish study in 1991 found that almost twice as many women as men were employed in jobs characterised by high job demands and a low degree of control, which in some studies have been found to have adverse health effects. Thus, many employed women are exposed to potentially hazardous factors at work.
It was in such a backdrop Dr Yrsa Andersen Hundrup, Research Centre for Prevention and Health, Glostrup University hospital and her colleagues took up a Danish Nurse Cohort Study, covering more than 12,000 female nurses aged between 45 and 64. The scientists tracked the health of the nurses for 15 years up to 2008, seeking to investigate the effect of work pressure and job influence on the development of IHD in women.
By the end of the study period, 580 nurses had been admitted to hospital with ischaemic heart disease, including 369 cases of angina and 138 heart attacks.
After accounting for risk factors such as smoking and diabetes, the researchers found that those who described pressure at work as "much too high" were 35% more likely to have developed heart disease than those who were comfortable with the pressure.
Nurses who reported work pressure to be much too high had an age adjusted 50% elevated risk of developing IHD compared to nurses who reported the work pressure to be suitable, whereas nurses who reported the work pressure to be a little too high had a smaller but still significant increased risk of developing IHD. It is noteworthy that the association between high work pressure and IHD was only significant among the younger nurses.
Furthermore, having work pressure that was much too high was a significant predictor of IHD even when angina pectoris was excluded both in age adjusted analyses and when controlling for traditional cardiovascular risk factors, shift work and physical activity at work.
A European prospective multi-centre study from 2006 found that men exposed to high psychosocial job demands had a nearly 50% increased risk of developing a coronary event. A contemporary Danish cohort study of men found a consistent association between psychological job demands and the risk of IHD, and in the Whitehall II Study high job demands increased the risk of coronary heart disease
events in both men and women.
More studies are needed to determine the extent to which duration and continuity of exposure may influence the size of the risk and whether the harm caused by work related stress is irreversible or attenuated as time passes since the exposure ceased. It is also important to study the mechanisms by which work related factors might lead to IHD, for example, whether the exposure causes atherosclerosis or whether it triggers IHD in individuals who already have atherosclerosis, the researchers said in their article published in Occupational and Environmental Medicine.
June Davison, a cardiac nurse with the British Heart Foundation, said people who were stressed at work should talk to colleagues or managers about how to manage the pressures.
"If you feel under pressure you should try and tackle it in a positive way and get active during work hours," she said.
"Using the stairs and walking some of the way to work could help act as a stress buster and boost heart health too."