In primary care, it will always be important to address the socio-demographic causes of disease and comorbidity.
- Dr Oliver van Hecke, DPhil Student and Oxfordshire-based GP
Genes play a key role in determining whether someone experiences multiple chronic diseases, according to new research from the Universities of Dundee and Oxford with Kings College, London.
Chronic pain, depression and heart disease are three of the commonest causes of disability, and are becoming more prevalent. People are also increasingly likely to suffer from more than one chronic disease, resulting in greater disability.
While age, gender, social circumstances and lifestyle are known to increase susceptibility to multiple causes of disability, the exact reason why some people suffer from several chronic diseases and others don’t is unknown. A new study, however, has found that genetics are also a key determinant.
Researchers examined two major existing population cohorts (Generation Scotland and TwinsUK), for the co-occurrence of chronic pain, depression and heart disease in both individuals and in their siblings. People who had one of these illnesses were found to be much more likely to have one or both of the others. Additionally, the brothers or sisters of people with one of these illnesses were much more likely to have one of the others, even after allowing for known social and demographic factors.
“These results have the potential to lead to a new model of chronic disease,” said Blair Smith, Professor of Population Science at Dundee’s School of Medicine. “They demonstrate, for the first time, that genes are important in determining the risk both of chronic disease itself, and of co-occurrence of disabilities.
“Our results strongly suggest that these chronic diseases, and potentially others, have shared common biological causes, in addition to known social and demographic factors. Further research is required to identify these causes, including the genes involved, in order that we can cut them off at an early stage.”
The findings may have implications for the early recognition of conditions in primary care.
“In primary care, it will always be important to address the socio-demographic causes of disability and comorbidity,” said the study’s lead author Dr Oliver van Hecke, DPhil student in Oxford University’s Nuffield Department of Primary Care Health Sciences and part-time Oxfordshire GP. “It is possible that a better understanding of the shared genetics of comorbidities may in the future allow for early recognition of conditions, preventative therapy, and the potential to target the underlying causes (such as stress or health inequalities) rather than the visible symptoms of the condition itself.”
The researchers found that people with depression were two and half times more likely to experience chronic pain, while people with both depression and heart disease were nine times more likely to do so. Siblings of people with heart disease were twice as likely to have chronic pain, while siblings of those with depression were twice as likely to suffer from heart disease.
Detailed modelling of data confirmed a genetic contribution to the co-occurrence of chronic widespread pain and heart disease in twins, in addition to important environmental contributions.
The results of the study are published today in the journal PLOS ONE and can be found at http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0170653.