Mental Health Scores but not Sleep Quality are Lower in Veterans with Gulf War Illness that have Low Physical Function

PURPOSE: Gulf War Illness (GWI) is a poorly understood illness that impacts about a third of Veterans who were deployed to the Gulf Region during the 1990-1991 Gulf War (GW). GW Veterans have twice the odds of having depression compared to non-deployed Veterans. Depression and sleep quality are associated with impaired physical function, which is notable since physical activity is a modifiable health behavior that can be an effective method to reduce mild to moderate depressive symptoms and improve sleep. We hypothesize that Veterans categorized with GWI and with high physical function scores will have fewer depressive symptoms and better sleep quality compared to those with low physical function. Evaluating the connection between physical and mental health in Veterans with GWI could support behavioral health interventions intended to improve symptom management. Methods: GW Veterans were enrolled in an ongoing VA multi-site remote clinical research study and completed web-based questionnaires: the Modified Kansas questionnaire, short-form 36 (SF-36), Patient Reported Outcomes Measurement Information System (PROMIS)-Emotional Distress Anxiety and Depression, and the Pittsburgh Sleep Quality Index (PSQI). The modified Kansas was used to designate GWI based on 6 self-reported symptom domains. Symptom onset was also required within 5 years of deployment. The SF-36 assessed eight functional domains, including physical functioning measuring mobility disability. GW Ill Veterans were grouped based on the SF-36 physical function score such that those with ≤70 were considered in the poor physical function group (low) and >70 were in the high physical function group (high). The PROMIS Anxiety assessed anxiety and PROMIS Depression assessed negative mood and decreased positive affect. The PSQI global score assessed sleep quality over a one-month period and ranges from 0-21 where a greater score reflects poorer sleep quality. Data were analyzed using student t-tests and linear regressions using Graphpad Prism 9. RESULTS: 63 Veterans (low group: 12 females/35 males, 60±4 years old; high group: 3 females/13 males, 59±5 years old) completed the web-based questionnaires. Anxiety and depression scores were greater in the low vs high group (Anxiety= low: 70.0±29; high: 45.4±14.0, P=0.001; Depression= low: 64.2.0±34.5; high: 41.3±14.7, P=0.01). Sleep quality (low: 12.8±4.0; high: 11.9±4.7, P=0.44) was not different between the groups. Anxiety scores (R2=0.19, P=0.0004) and depression scores (R2=0.11, P=0.007) were related to physical function, thus greater physical function was associated with lower (better) mental health scores. Sleep quality (R2=0.07, P=0.03) was related to physical function, so greater physical function was associated with better sleep quality. CONCLUSIONS: Gulf War Illness is a chronic multi-symptom condition that can be debilitating. Insight about physical function, depression and sleep symptoms could guide therapeutic approaches. The SF-36 is recommended as a core data element in GWI research and as such can provide information on the physical aspects of health. These findings suggest that depression and anxiety differ in those with low versus high physical function and that physical function is related to mental health and sleep quality. Future research should examine how GW Veterans are able to maintain their physical function to improve overall health. VA CSR&D. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.