A comprehensive meta-analysis of data from the UK Biobank found a different genetic basis for chronic pain in women compared to men.
The results are still preliminary, but to date it is one of the largest genetic studies on chronic pain to analyze the female and male sex separately.
“Our study highlights the importance of considering sex as a biological variable and has shown subtle but interesting gender differences in the genetics of chronic pain,” says population geneticist Keira Johnston of the University of Glasgow in Scotland.
Chronic pain conditions are one of the most common, unfit and expensive conditions in public health. In the United States, chronic pain affects more people than joint heart disease, diabetes, and cancer, and yet it receives a fraction of the total funding.
Even when studies are done, the underlying gender differences are often overlooked, and this is a major and detrimental oversight. Compared to men, women are much more likely to develop multiple chronic pain disorders, and yet 80 percent of all pain studies have been done on male mice or male humans. This means that we know very little about how and why women suffer more and what treatments can best help them.
Although there are probably several biological and psychosocial processes in this gender diversity, the current genome-wide study indicates that there is also a genetic factor in the mixture.
Comparing gene variants associated with chronic pain in 209,093 women and 178,556 men from the UK Biobank, researchers tried to find at least part of the answer in our biology.
Finally, researchers found 31 genes associated with chronic pain in women and 37 genes associated with chronic pain in men with barely any overlap. The authors admit that some of the differences here are due to their lower sample size, but the results are nonetheless interesting.
When researchers tested the expression of all these genetic variants in different tissues of mice and humans, they noticed that the vast majority were active in a group of nerves within the spinal cord, known as the dorsal root ganglion, which carry messages from the body to the body transfer. brain.
Several genes in the list for males or females only are associated with psychiatric problems or immune function, but only one gene, known as DCC, was in both lists.
DCC encodes a receptor that binds to a protein that is essential for the development of the nervous system, especially the dopaminergic system; Besides being a reward center, it has recently been linked to pain modulation in the body.
DCC is also thought to be a risk gene for the pathology of depression, and DCC mutations occur in those with congenital mirror movement disorder, leading to repetitive movements on one side of the body on the other.
Exactly how DCC is linked to chronic pain remains unclear, but the authors believe their results support a number of theories about strong nervous system and immune involvement in chronic pain in both sexes, hoping to develop better treatments in the future.
If chronic pain is more strongly associated with immune function in women, the side effects of medicines that are immune can be very different from men. On the other hand, treatments such as chronic opioid use can also have different outcomes. Opioids are known to adversely affect immune function, suggesting that it may make things worse and not better for women with chronic pain.
For now, these are just ideas. Much more research needs to be done on pain, and much more needs to be done among women before we can really begin to understand the real gender differences and what we can do about them.
“All of this evidence suggests putative central and peripheral neuronal roles for some of these genes, many of which have not been historically well studied in the field of chronic pain,” the authors conclude.
The study was published in PLOS Genetics.