London: People who frequently experience violence or bullying at work may be at higher risk of heart attacks and stroke, a study has found.
The researchers looked at data from 79,201 working men and women in Denmark and Sweden, aged 18 to 65, with no history of cardiovascular disease (CVD), who were participants in three studies that started between 1995 and 2011.
Although the study does not show that workplace bullying or violence directly cause cardiovascular problems, researchers said that their results are robust and have important implications for employers and national governments.
"If there is a causal link between bullying or violence at work and cardiovascular disease, then the removal of workplace bullying would mean we could avoid five per cent of all cardiovascular cases, and the eradication of violence at work would avoid more than three per cent of all cases," said Tianwei Xu, a PhD student at the University of Copenhagen in Denmark.
When the participants joined the studies, the participants were asked about bullying and violence in the workplace and how frequently they experienced each of them.
Information on the number of cases of heart and brain blood vessel disease and deaths was obtained from nationwide registries.
Researchers also took account of other factors that could affect whether or not the participants were affected by CVD, such as body mass index, alcohol consumption, smoking, mental disorders and other pre-existing health conditions, shift working and occupation.
Nine per cent of participants reported being bullied at work and 13 per cent reported experiencing violence or threats of violence at work in the past year.
After adjusting for age, sex, country of birth, marital status and level of education, the researchers found that those who were bullied or experienced violence (or threats of violence) at work had a 59 per cent and 25 per cent higher risk of CVD respectively compared to people who were not exposed to bullying or violence.
The more bullying or violence that was encountered, the greater the risk of CVD.
People who reported being bullied frequently in the past 12 months had 120 per cent higher risk of CVD, while those who were exposed most frequently to workplace violence had a 36 per cent higher risk of cerebrovascular disease (such as stroke) than those not exposed to violence, but there did not appear to be a corresponding increase in heart disease.
"Workplace bullying and workplace violence are distinct social stressors at work. Only 10-14 per cent of those exposed to at least one type of exposure were suffering from the other at the same time," said Xu.
These stressful events are related to a higher risk of cardiovascular disease in a dose-response manner -- in other words, the greater the exposure to the bullying or violence, the greater the risk of cardiovascular disease.
The researchers are currently investigating what mechanisms, behavioural and biological, may be involved in increasing the risk of CVD in people who experience workplace bullying or violence.
They believe that high blood pressure is likely to be involved as it is known already that severe stress can increase blood pressure.
In addition, exposure to bullying and violence may lead to anxiety and depression which, in turn, can lead to over-eating and excessive alcohol consumption. Stress-induced changes to metabolism could also be involved.