"Although the relationship between significant distress and the onset of arthritis, [chronic pulmonary obstructive disorder], cardiovascular disease, and diabetes is well established," says Prof. Catharine Gale, from the University of Southampton in the United Kingdom, "there is a significant gap in knowledge regarding the link between lower and moderate levels of distress and the development of chronic conditions."
Alongside Kyle McLachlan, at the University of Edinburgh in the U.K., Prof Gale conducted a study investigating whether exposure to low and moderate psychological distress — which includes symptoms of anxiety and depression — could increase the risk of developing a chronic disease.
The results, which have now been published in the Journal of Psychosomatic Research, indicate that we do not need to experience a lot of distress in order for our physical health to be endangered. A little distress will suffice, the authors warn.
Reducing distress may prevent disease onset
In the new study, the researchers analyzed relevant data collected from 16,485 adults for a period of 3 years. Prof. Gale and McLachlan obtain this information using the UK Household Longitudinal Study, which gathers data regarding the health status, well-being, and living conditions — among other things — of U.K. citizens.
They looked specifically for links between psychological distress and the development of four chronic diseases: diabetes, arthritis, lung disease, and cardiovascular disease.
They also investigated whether any such association could be explained by modifiable factors such as eating habits, exercise, or smoking, or by participants' socioeconomic status.
Prof. Gale and McLachlan's study found that, despite the fact that they are not considered clinically significant, even low to moderate levels of experienced distress can heighten the risk for a chronic condition later in life.
"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."
Prof. Catharine Gale
Compared with people who reported no symptoms of psychological distress, those who reported low distress levels were 57 percent more likely to develop arthritis.
Also, those experiencing moderate levels of distress were 72 percent more likely to develop this condition, and individuals reporting high distress levels were 110 percent more likely.
Similar associations were also found for cardiovascular disease and lung disease (specifically, chronic obstructive pulmonary disease [COPD]).
In fact, people with low levels of distress were 46 percent more likely to develop cardiovascular problems, those with moderate levels had a 77 percent higher risk, and those exposed to high levels of distress had a 189 percent higher risk.
For lung disease, the risk did not rise in people reporting low distress levels, but it was heightened by 125 percent in those with moderate distress levels, and by 148 percent in people with high distress levels.
However, the researchers found no significant links between psychological distress and the development of diabetes.
'Considerable public health implications'
The researchers note that the new study's results could change the way in which public health policies consider risk factors for chronic diseases.
"These findings have considerable clinical and public health implications," explains Prof Gale.
"Screening for distress," she explains, "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."
Distress is a potentially modifiable risk factor, so if the links found by this study are confirmed by further research, it could indicate a new pathway in terms of preventive strategies for chronic diseases.
Prof. Cyrus Cooper, the director of the Lifecourse Epidemiology Unit at the UK Medical Research Council, believes that Prof. Gale and McLachlan's findings have "the potential to have a major impact on the development and management of chronic diseases."
Dr. Iain Simpson, former president of the British Cardiovascular Society, states that "cardiovascular disease remains one of the major causes of death and disability," so "[the] knowledge that distress, even at low levels, is also a risk factor is an important finding which could have significant clinical implications."