Active elite rugby participation is associated with altered precentral cortical thickness

Abstract There is growing concern that elite rugby participation may negatively influence brain health, but the underlying mechanisms are unclear. Cortical thickness is a widely applied biomarker of grey matter structure, but there is limited research into how it may be altered in active professional rugby players. Cross-sectional MRI data from 44 active elite rugby players, including 21 assessed within one week of head injury, and 47 healthy controls were analysed. We investigated how active elite rugby participation with and without subacute traumatic brain injury influenced grey matter structure using whole cortex and region of interest cortical thickness analyses. Relationships between cortical thickness and biomarkers of traumatic brain injury, including fractional anisotropy, plasma neurofilament light and glial fibrillary acidic protein, were also examined. In whole cortex analyses, precentral cortical thickness in the right hemisphere was lower in rugby players compared with controls, which was due to reductions in non-injured players. Post-hoc region of interest analyses showed non-injured rugby players had reduced cortical thickness in the inferior precentral sulcal thickness bilaterally (p = 0.005) and the left central sulcus (p = 0.037) relative to controls. In contrast, players in the subacute phase of mild traumatic brain injury had higher inferior precentral sulcal cortical thickness in the right hemisphere (p = 0.015). Plasma glial fibrillary acidic protein, a marker of astrocyte activation, was positively associated with right inferior precentral sulcal cortical thickness in injured rugby players (p = 0.0012). Elite rugby participation is associated with localised alterations in cortical thickness, specifically in sulcal motor regions. Subacute changes after mild TBI are associated with evidence of astrocytic activation. The combination of cortical thickness and glial fibrillary acidic protein may be useful in understanding the pathophysiological relationship between sporting head injury and brain health.