Pain sensitivity influenced by lifestyle, environment: twin study suggests

Sensitivity to pain could be altered by a person's lifestyle and environment throughout their lifetime, according to a new study published on Tuesday in Nature Communications. Pain sensitivity was previously thought to be relatively inflexible, however, researchers at King's College London challenged this view with their twin study. They suggested that it can change as a result of genes being switched on or off by lifestyle and environmental factors. The process was called "epigenetics", which chemically alters the expression of genes. Identical twins share 100 percent of their genes. Therefore, any difference between identical twins must be due to their environment or epigenetic changes affecting the function of their genes, making them ideal participants for a study of this nature. To identify levels of sensitivity to pain, scientists tested 25 pairs of identical twins using a heat probe on the arm. Using DNA sequencing, the researchers examined over 5 million epigenetic marks across the whole genome and compared them with a further 50 unrelated individuals to confirm their results. The research team found wide variations between people and identified chemical modifications within nine genes involved in pain sensitivity that were different in one twin but not in her identical sister. The chemical changes were most significant within a known pain sensitivity gene, TRPA1. Lead author of the study, Dr Jordana Bell, said that: "The potential to epigenetically regulate the behavior of TRPA1 and other genes involved in pain sensitivity is very exciting, and could lead to a more effective pain relief treatment for patients suffering with chronic pain."