Chronic pain and differential brain morphology alterations of childhood maltreatment, trauma exposure in adulthood and their cumulative effects in the UK Biobank

BackgroundChronic pain is associated with heightened prevalence of trauma exposure. Separate studies of chronic pain and trauma report overlapping brain alterations in older adults (age over 60). Despite this close relationship, the interplay between chronic pain and trauma on brain morphology remains poorly understood. MethodsTabulated T1-weighted structural magnetic resonance imaging data were accessed from the UK biobank (N = 21,996). Linear mixed models were used to determine the main effects of group (control versus chronic pain), severity of trauma exposure and their interaction on measures of surface area, cortical thickness and subcortical volume. To examine the unique and cumulative impacts of trauma exposure at different developmental timing, group of participants exposed to childhood maltreatment only, trauma in adulthood only and both were derived. ResultsIndependently of the severity of trauma exposure, chronic pain was significantly associated with smaller surface area and thicker frontal, temporal, parietal, somatosensory, occipital and cingulate cortices. Independently of chronic pain, the severity of trauma exposure in adulthood and both childhood and adulthood, but not childhood alone, were associated with smaller bilateral nucleus accumbens, putamen, thalamus and left hippocampal volumes, as well as left inferior parietal gyrus surface area. No chronic pain-by-trauma severity interactions were significantly associated with variations in any regional measures. ConclusionsSpecific effects of chronic pain and trauma severity were evident among older adults exposed to trauma at different developmental timing. However, there was no evidence for unique brain signatures representing the combined effects of chronic pain and trauma in older adults.