Chronic musculoskeletal pain (CMP) affects 25%-35% of Gulf War Veterans (GV). Neuroimaging data suggest that CMP is associated with alterations in brain structure. Physical activity (PA) positively relates to physical function and negatively relates to symptoms in CMP. However, the relationships between PA, sedentary behaviors (SB) and brain structure are poorly understood. This study investigated the relationship between cerebral white matter integrity (WMI), PA, SB and pain symptoms in GV with CMP. Thirty GVCMP and 31 matched Veteran controls (GVCO) completed a 3T MRI scan with diffusion tensor imaging (DTI- 48 non-collinear directions). PA was measured using accelerometry. Pain symptoms were measured using validated questionnaires (eg. MPQ, FIQ). Tract-based Spatial Statistics estimated WM fractional anisotropy and mean, radial and axial diffusivities over the whole brain (p < 0.05), corrected using a threshold-free cluster enhancement. Group comparisons were conducted using linear mixed-effects analyses. Standard linear regression models assessed relationships among WMI, PA, SB, and pain symptoms. Results showed that GVCMP were less physically active (p < 0.05), but not more sedentary than GVCO (p > 0.05). In GVCMP, greater amounts of PA and lower amounts of SB were significantly associated with fewer pain symptoms (p < 0.05). Compared to GVCO, GVCMP had lower WMI in brain regions implicated in chronic pain (p < 0.05). WMI was associated with pain symptoms and PA in the corona radiata and posterior thalamic radiation of GVCMP (p < 0.05). Our results suggest that WM microstructure is disrupted in GVCMP, and that these disruptions are related to PA, SB and pain symptoms. Interventions aimed at increasing PA or reducing SB and determining the impact of these changes on both WMI and symptoms are needed to further explore the benefits of a physically active lifestyle in Gulf War Illness.
Van Riper, S., Stegner, A., Ellingson, L., Koltyn, K., Alexander, A., & Cook, D. (2016). (229) Investigation of cerebral white matter integrity, physical activity behaviors and pain symptoms in Gulf War Veterans with chronic musculoskeletal pain. The Journal of Pain, 17(4), S33. https://doi.org/10.1016/j.jpain.2016.01.133