Low levels of psychological distress can increase the risk of developing some chronic diseases including arthritis, and types of heart and lung disease, according to new research.
The study, led by Catharine Gale, a professor of cognitive epidemiology at the Medical Research Council's Lifecourse Epidemiology Unit at Southampton General Hospital, assessed 16,485 UK adults over a three-year period.
Results, published in the Journal of Psychosomatic Research, showed that distress, even at low or moderate levels, was a significant risk factor in developing conditions such as chronic obstructive pulmonary disease (COPD), arthritis and cardiovascular disease.
The chances of developing arthritis were 57% higher in those with low levels of distress, 72% higher in those with moderate levels and 110% higher in those with high levels
Psychological distress is a term that describes a wide range of mental health symptoms, from mild anxiety and depression to severe psychiatric disease.
Prof. Gale said: "Although the relationship between significant distress and the onset of arthritis, COPD, cardiovascular disease and diabetes is well established, there is a significant gap in knowledge regarding the link between lower and moderate levels of distress and the development of chronic conditions.
"Our findings show that even low levels of distress, below the level usually considered clinically significant, appear to increase the risk of developing a chronic disease, so intervention to reduce symptoms of anxiety and depression may help to prevent the onset of these illnesses for some people."
The study used data from the UK Household Longitudinal Study (UKHLS) to examine whether level of psychological distress was linked with the later development of several chronic diseases and whether any link was explained by health habits - such as diet, exercise and smoking - or socioeconomic status.
The UKHLS began in 2009 and gathers data on health, psychological factors, and socioeconomic status annually from a population sample selected from 39,802 UK households, with participants asked to indicate how frequently they experience 12 common symptoms of psychological distress.
The study found that compared to people with no symptoms of distress, the chances of developing arthritis were 57% higher in those with low levels of distress, 72% higher in those with moderate levels and 110% higher in those with high levels.
For cardiovascular disease, compared to people with no symptoms of distress, the risk of developing this condition was 46% higher in those with low levels of distress, 77% higher at moderate levels and 189% higher in those with high levels, while for COPD the risk was only increased in those with moderate (125%) or high (148%) levels of distress.
There were no significant associations between psychological distress and risk of diabetes.
Prof. Gale added: "These findings have considerable clinical and public health implications. Screening for distress may help to identify those at risk of developing arthritis, COPD and cardiovascular disease, while interventions to improve distress may help to prevent and limit progression of disease, even for people with low levels of distress."
Cyrus Cooper, a consultant rheumatologist and director of the Medical Research Council's Lifecourse Epidemiology Unit, said: "This fascinating data has the potential to have a major impact on the development and management of chronic diseases, which could not only save and change lives but also significantly reduce costs across the health service."