People who are bullied at work may have an increased risk of suffering a heart attack or stroke, the results of a new study suggest.

Researchers in Denmark looked at over 79,000 working men and women aged between 18 and 65, with no history of cardiovascular disease (CVD). All have been monitored since the 1990s as part of three ongoing studies.

Overall, 9% reported being bullied at work over the last year, while 13% said that they had experienced violence or threats of violence.

The study found that those who were bullied at work had a 59% increased risk of developing CVD, compared to those who were not bullied at work. Those who experienced violence or threats of violence had a 25% increased risk of developing CVD.

CVD includes all diseases of the heart and circulatory system, but most commonly refers to blood vessel conditions such as heart attack and stroke. It is the most common cause of death and disability in Ireland.

The researchers took into account other factors that may have affected the results, such as smoking, body mass index (BMI) and occupation. They also adjusted for factors such as age, marital status and level of education.

They found that the more bullying or violence a person was exposed to, the greater the risk of CVD. For example, people who said they were bullied almost every day in work over the last year had a 120% increased risk of developing CVD compared to those who were not bullied.

Meanwhile, those most often exposed to workplace violence had a 36% increased risk of suffering a cerebrovascular event, such as a stroke.

"Workplace bullying and workplace violence are distinct social stressors at work. These stressful events are related to a higher risk of CVD in a dose-response manner. In other words, the greater the exposure to the bullying or violence, the greater the risk of CVD.

"From this study we cannot conclude that there is a causal relation between workplace bullying or workplace violence and CVD, but we provide empirical evidence in support of such a causal relation, especially given the plausible biological pathway between workplace major stressors and CVD," commented the researchers from the University of Copenhagen.

They suggested that the effects of bullying and violence on the incidence of CVD within the general population is comparable to other risk factors, such as diabetes and the consumption of alcohol.

"It is important to prevent workplace bullying and workplace violence from happening, as they constitute major stressors for those exposed. It is also important to have policies for intervening if bullying or violence occurs.

"If there is a causal link between bullying or violence at work and CVD, then the removal of workplace bullying would mean we could avoid 5% of all cardiovascular cases, and the eradication of violence at work would avoid more than 3% of all cases," the researchers added.

They are currently investigating why bullying appears to increase the risk of CVD.

Details of these findings are published in the European Heart Journal.