Ocular and inflammatory markers associated with Gulf War illness symptoms

To examine the utility of ocular coherence tomography (OCT) metrics, in conjunction with systemic markers of inflammation, in identifying individuals with Gulf War Illness (GWI) symptoms. Prospective case-control study of 108 Gulf War Era veterans, split into 2 groups based on the presence of GWI symptoms, defined by the Kansas criteria. Information on demographics, deployment history, and co-morbidities were captured. 101 individuals underwent OCT imaging and 105 individuals provided a blood sample which was analyzed for inflammatory cytokines using an enzyme-linked immunosorbent assay-based chemiluminescent assay. The main outcome measure was predictors of GWI symptoms, examined with multivariable forward stepwise logistic regression analysis followed by receiver operating characteristic (ROC) analysis. The mean age of the population was 55 +/- 4, 90.7% self-identified as male, 53.3% as White, and 54.3% as Hispanic. A multivariable model that considered demographics and co-morbidities found that a lower inferior temporal ganglion cell layer-inner plexiform layer (GCLIPL) thickness, higher temporal nerve fiber layer (NFL) thickness, lower interleukin (IL)-1 beta levels, higher IL-1 alpha levels, and lower tumor necrosis factor-receptor I levels correlated with GWI symptoms. ROC analysis demonstrated an area under the curve of 0.78 with the best cut-off value for the prediction model having a sensitivity of 83% and specificity of 58%. RNFL and GCLIPL measures, namely increased temporal thickness and decreased inferior temporal thickness, respectively, in conjunction with a number of inflammatory cytokines, had a reasonable sensitivity for the diagnosis of GWI symptoms in our population.

Automated summary

This prospective case-control study aimed to investigate the utility of ocular coherence tomography (OCT) metrics and systemic markers of inflammation in identifying individuals with Gulf War Illness (GWI) symptoms. The study included 108 Gulf War Era veterans, and the results showed that certain OCT measures, such as increased temporal thickness and decreased inferior temporal thickness, along with specific inflammatory cytokines, were correlated with GWI symptoms. The ROC analysis demonstrated a reasonable sensitivity and specificity for the diagnosis of GWI symptoms in this population.