Anxiety and depression may significantly increase the risk of heart disease, stroke and arthritis, comparable to smoking and obesity, a study warns. Researchers from the University of California, San Francisco (UCSF) in the US looked at the health data of more than 15,000 older adults over a four-year period. The study, published in the journal Health Psychology, found that 16 per cent (2,225) suffered from high levels of anxiety and depression, 31 per cent (4,737) were obese and 14 per cent (2,125) were current smokers. Participants with high levels of anxiety and depression were found to face 65 per cent increased odds for a heart condition, 64 per cent for stroke, 50 per cent for high blood pressure and 87 for arthritis, compared to those without anxiety and depression. "These increased odds are similar to those of participants who are smokers or are obese," said Aoife O'Donovan from UCSF. "However, for arthritis, high anxiety and depression seem to confer higher risks than smoking and obesity," O'Donovan said. Unlike the other conditions investigated, the researchers found that high levels of depression and anxiety were not associated with cancer incidence. This confirms results from previous studies, but contradicts a prevailing idea shared by many patients, researchers said. "Our findings are in line with a lot of other studies showing that psychological distress is not a strong predictor of many types of cancer," O'Donovan said. "On top of highlighting that mental health matters for a whole host of medical illnesses, it is important that we promote these null findings. We need to stop attributing cancer diagnoses to histories of stress, depression and anxiety," O'Donovan said. The researchers discovered that symptoms such as headache, stomach upset, back pain and shortness of breath increased exponentially in association with high stress and depression. Odds for headache, for example, were 161 per cent higher in this group, compared with no increase among the participants who were obese and smokers. "Anxiety and depression symptoms are strongly linked to poor physical health, yet these conditions continue to receive limited attention in primary care settings, compared to smoking and obesity," said Andrea Niles from UCSF. "To our knowledge this is the first study that directly compared anxiety and depression to obesity and smoking as prospective risk factors for disease onset in long-term studies," Niles said.