Self-Reported Autonomic Dysregulation in Gulf War Illness

Autonomic nervous system dysregulation is commonly observed in Gulf War illness (GWI). Using a new sample, we sought to replicate and extend findings from a previous study that found autonomic symptoms predicted physical functioning in Veterans with GWI.

A linear regression model was used to predict physical functioning (36-item Short Form Health Survey (SF-36); n = 73, 75% male). First, we examined the predictive value of independent variables individually in the model including: the 31-item Composite Autonomic Symptom Score (COMPASS-31) total score, body mass index (BMI), mental health burden (i.e., post-traumatic stress disorder [PTSD] and/or depression), and COMPASS-31 subscales: orthostatic intolerance, vasomotor, secretomotor, gastrointestinal, bladder, and pupillomotor. Next, we estimated linear regression models containing the three variables (autonomic symptoms, BMI, and mental health burden) identified as predictors of physical functioning from the prior study.

These linear regression models significantly predicted physical functioning and accounted for 15% of the variance with COMPASS-31, 36.6% of variance with COMPASS-31 and BMI, and 38.2% of variance with COMPASS-31, BMI, and mental health burden. Then, forward step-wise linear regressions were applied to explore new models including COMPASS-31 subscales. Two new models accounted for more of the variance in physical functioning: 39.3% with added gastrointestinal symptoms (β = -2.206, P = .001) and 43.4% of variance with both gastrointestinal (β = -1.592, P = .008) and secretomotor subscales (β = -1.533, P = .049). Unlike the previous study we intended to replicate, mental health burden was not a significant predictor in any of our models.

Treatments that address autonomic dysregulation should be prioritized for research and clinical recommendations for Veterans with GWI who experience chronic pain.