Open Burn Pit Exposure in Headache Disorder and Migraine.

Importance: Open burn pits have commonly been used for waste disposal by the US military but have not been systematically investigated as an independent risk factor for headache disorders. Objective: To evaluate the association between exposure to open burn pits and incidence of headache and migraine. Design, Setting, and Participants: This retrospective cohort study used data from the Veterans Health Administration Headache Cohort along with data from the US Department of Defense and the Airborne Hazards and Open Burn Pit (AH&OBP) Registry to assess registry participants with potential exposure to open burn pits in the Veterans Health Administration from April 1, 2014, through October 31, 2022. Participants were included by linking data from the AH&OBP Registry to their US Department of Defense and Veterans Health Administration electronic health records. Those with preexisting headache were removed from the analytic sample. The analysis was conducted between November 1, 2022, and January 31, 2024. Exposure: Open burn pit exposure composite variables based on the registry questionnaire were examined, specifically being near open burn pits, days near open burn pits, and having open burn pit duties. Main Outcomes and Measures: Primary incident outcomes included medically diagnosed headache disorders and medically diagnosed migraine. Results: The analytic sample included 247 583 veterans (mean [SD] age, 27.9 [7.7] years; 222 498 [89.9%] male). After covariates were controlled for at baseline, participants who were near an open burn pit with open burn pit duties had the highest adjusted odds of medically diagnosed headache disorders (adjusted odds ratio [AOR], 1.59; 95% CI, 1.46-1.74), migraine (AOR, 1.60; 95% CI, 1.43-1.79), and self-reported disabling migraine (AOR, 1.93; 95% CI, 1.69-2.20) compared with those without exposure. The 2 highest quartiles of cumulative burn pit exposure (290-448 days and >448 days) had significantly higher adjusted odds of medically diagnosed headache (290-448 days: AOR, 1.20; 95% CI, 1.09-1.31; >448 days: AOR, 1.55; 95% CI, 1.41-1.70) and migraine (290-448 days: AOR, 1.19; 95% CI, 1.07-1.34; >448 days: AOR, 1.48; 95% CI, 1.32-1.65). Conclusions and Relevance: In this cohort study, a dose-dependent association existed between open burn pit exposure and medically diagnosed headache and migraine. These new data identify potentially important associations between open burn bit exposure and new-onset headache among service personnel as well as a possible health condition that may be encountered more frequently in Veterans Health Administration facilities during mandatory screening for military exposures.