Investigating a clinically informed sleep disturbance threshold for physical and mental health among Gulf War Illness veterans.

STUDY OBJECTIVES: This study (1) assessed sleep quality and health in Gulf War veterans (GWV) meeting the Gulf War Illness (GWI) criteria and (2) compared health associations for both those meeting a "clinically disturbed sleep" threshold, and those below, as determined by the Pittsburgh Sleep Quality Index (PSQI) cutoff for military populations (≥10) on measures of physical, mental, and cognitive health.

METHODS: Participant data consisted of questionnaires and assessments completed prior to group assignment in a clinical trial. The sample consisted of 147 GWV, where 81.0% were males, and the median age was 53.4 years.

RESULTS: The mean (SD) PSQI global score was 12.34 (4.00) with 61% of the sample qualifying as clinically disturbed sleepers according to the cutoff (global PSQI ≥ 10). GWI veterans with PSQI scores ≥10 did not differ from others in age ( p  = 0.20), sex ( p  = 0.19), or years of education ( p  = 0.87), but showed worse GW-related symptomology on the Gulf War Kansas questionnaire ( p  < 0.01), and poorer mental health on the Veterans Rand-36 ( p  < 0.01).

CONCLUSIONS: Disturbed sleep was associated with measures of pain, fatigue, and cognitive health. Our results suggest that a previously determined clinical threshold for clinically disturbed sleep is useful when examining the health status of the study population. Given that GWI is associated with elevated PSQI scores and a high frequency of disturbed sleep, cutoffs determining sleep health should be sensitive to population exposures and health history to improve interpretability.