A study looking at the health of a cohort of 7,052 people has found that those who had anxiety about their health were much more likely to go on to develop ischaemic heart disease.

Researchers at Sandviken University Hospital in Norway looked at the link between health anxiety and heart disease after adjusting for factors such as blood pressure, weight, cholesterol levels and family history – all factors known to affect the risk of developing heart disease.

Aside from these factors, they found in the study – published in the journal BMJ – that there is another significant risk factor, which is health anxiety.

Of patients who did not have health anxiety, 3% developed ischaemic heart disease. Of those with health anxiety, just over 6% developed the condition. After adjusting for the known factors associated with heart disease, the increased risk for those with health anxiety was 70%.

"We didn't expect such a strong effect," study author Line Iden Berge, psychiatrist at Sandviken University Hospital, told IBTimes UK.

The epidemiological study only found a figure to put on the added risk due to anxiety, not the causes of it, Berge says. "But we reckon that there's something about the anxiety and how it works on biological processes in the body that can explain it," she says.

"For example other studies have shown that people with anxiety in general have reduced heart rate variability as well as increased rate of the atherosclerosis process. So we speculate that those mechanisms could be the ones working here."

The findings of Berge's study have implications for health professionals and patients, she says. There is too little awareness of the health problems that can be caused by anxiety in the long run, she says. A lack of communication of the risks associated with anxiety has led to poor public understanding of the problem, she says.

Berge urges people with anxiety to seek medical advice. "Patients with anxiety really need to acknowledge this and receive proper treatment."

The patients studied for the paper were part of the Norwegian Hordaland Health Study, a long term collaborative research project between the National Health Screening Service, the University of Bergen, and local health services.