Link found between brain structure, genetics and chronic pain

Genetic factors partly explain the link between brain structure and chronic pain, according to research led by The University of Queensland (UQ). Published in the journal Brain, the work marks a step towards understanding the complex relationship between the brain and human genome in how they influence and contribute to chronic pain — the leading cause of disability worldwide.

Dr Scott Farrell, from UQ’s RECOVER Injury Research Centre, said chronic pain affects around one in five Australian adults, while musculoskeletal disorders have the highest expenditure across disease groups in the country’s healthcare system. “By identifying the underlying biological causes of chronic pain,” he said, “we hope to improve the diagnosis, treatment of and health outcomes for sufferers of this highly debilitating condition.”

The new study used UK Biobank genetic data from nearly 200,000 people with various chronic pain conditions and a separate cohort of 34,000 people who had undergone scans measuring the size of different brain regions. The various chronic pain conditions included neck, shoulder, back, hip, knee, abdominal and widespread chronic pain.

Dr Farrell said the team found genetic differences contributed to both an increased risk of certain chronic pain types and a reduction in size of specific brain regions. While differences in brain structure have previously been reported in people with chronic pain, the research shows for the first time that this association is partly due to individual differences in people’s DNA.

“A decrease in size of certain brain regions was thought to be a consequence of chronic pain; however, we found that reduced thickness in one particular area, the insular cortex, may contribute to a higher risk of chronic abdominal pain,” Dr Farrell said. The insular cortex is known to be involved in a range of functions including empathic pain perception, visceral sensation, taste, emotional processing and individuals’ internal perceptions of their body.

“This result was quite unexpected because prior clinical studies suggested changes in brain structure occur after the onset of chronic pain,” Dr Farrell said.

“The application of statistical genetic methods to large-scale pain and brain imaging data has shed new light on clinical pain research.”

Dr Farrell said the work builds on several other large genetic studies that delivered findings in mental health and neurological disorders, which are often compounded in people with chronic pain. He revealed, “We are conducting further analyses to determine the genetic causal relationships across many clinical, lifestyle and psychosocial factors known to be associated with chronic pain, to help identify the underlying factors for clinical translation.”

Image credit: ©stock.adobe.com/au/Antonioguillem

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