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. 2025 Mar-Apr;40(2):E121-E128.
doi: 10.1097/HTR.0000000000000989. Epub 2024 Jul 5.

Research Letter: Characterizing Lifetime Mild TBI Exposure Among Female and Male Military Service Members and Veterans in the LIMBIC-CENC Study

Samuel R Walton  1 , Jessie R Oldham, Rosemay A Remigio-Baker, Benjamin L Brett, Tara A Austin, Olivia D Cetin, Elisabeth A Wilde, Landon B Lempke, Zhining Ou, Sreekanth Kamineni, Sarah L Martindale, Maya E O'Neil, Mary J Pugh, Randel L Swanson, Monique R Pappadis, David X Cifu, William C Walker
Affiliations

Research Letter: Characterizing Lifetime Mild TBI Exposure Among Female and Male Military Service Members and Veterans in the LIMBIC-CENC Study

Samuel R Walton et al. J Head Trauma Rehabil. 2025 Mar-Apr.

Abstract

Objective: To (1) characterize lifetime mild traumatic brain injury (TBI) exposures among male and female US military service members and Veterans (SMVs) and (2) evaluate sex-related differences in mild TBI exposures.

Setting: Clinical research laboratory.

Participants: Participants were enrolled in the ongoing Long-term Impact of Military-relevant Brain Injury Consortium-Chronic Effects of Neurotrauma Consortium (LIMBIC-CENC) Prospective Longitudinal Study.

Design: Cross-sectional.

Main measures: Lifetime history of mild TBI was measured via structured interview. All mild TBI characteristics were collected as part of this interview, including total lifetime number; environment (deployment vs. non-deployment); timing of injury (relative to military service and age); and mechanism of injury (blast-related vs. non-blast).

Results: Most participants ( n = 2323; 87.5% male; 79.6% Veteran) reported ≥1 lifetime mild TBI ( n = 1912; 82%), among whom, many reported ≥2 lifetime mild TBIs. Female SMVs reported fewer total lifetime mild TBIs than male participants ( P < 0.001), including fewer deployment-related ( P < 0.001) and non-deployment ( P < 0.001) mild TBIs. There were significant sex differences for total number of mild TBIs sustained before ( P = 0.005) and during ( P < 0.001) military service but not after separation from military service ( P = 0.99). Among participants with a lifetime history of mild TBI, female SMVs were less likely to report ≥2 mTBIs ( P = 0.003); however, male SMVs were more likely to report a mild TBI during military service ( P = 0.03), including combat-related mild TBI ( P < 0.001) and mild TBI involving blast ( P < 0.001).

Conclusions: These findings inform clinical and research efforts related to mild TBI in US military SMVs. It may not be sufficient to simply measure the total number of mild TBIs when seeking to compare clinical outcomes related to mild TBI between sexes; rather, it is important to measure and account for the timing, environment, and mechanisms associated with mild TBIs sustained by female and male SMVs.

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Conflict of interest statement

Conflicts of Interest: Samuel R. Walton: Dr Walton reports separate funding support from the DoD & VA for projects related to the LIMBIC-CENC study; honorarium and conference travel support from the National Athletic Trainers’ Association and UCLA; serves in unpaid leadership roles with the World Federation of Athletic Training and Therapy (WFATT) and the Concussion in Sport Group (CISG); Jessie R. Oldham: Dr. Oldham receives support from the Thrasher Research Fund and National Institute of Arthritis and Musculoskeletal Skin Diseases (8K12AR084233-03); Benjamin L. Brett: Dr. Brett reports funding support from the NIA and NINDS, as well as honoraria and travel support as conference presentations; Elisabeth A. Wilde: Dr. Wilde receives grant funding support from the US Department of Veterans Affairs and the Department of Defense (related to this work and cited below) and from the National Institutes of Health (NINDS), and Vielight, Inc. (unrelated to this work); Rosemay A. Remigio-Baker: Dr. Remigio-Baker is a contractor from Compass Government Solutions that support the Traumatic Brain Injury Center of Excellence; Mary J. Pugh: Dr. Pugh reports separate funding support from the DoD & VA for projects not related to the LIMBIC-CENC study; Randel L. Swanson: Dr. Swanson reports separate funding support from the VA for a project related to the LIMBIC-CENC study and funding from the DoD and VA for projects not related to the LIMBIC-CENC study. Dr. Swanson was supported, in part, by the United States Department of Veterans Affairs Rehabilitation Research and Development Service under Award Number IK2 RX00365; Monique R. Pappadis: Receives grant funding support from the NIH/NIA (K01AG065492), NIMHD (L60MD009326L), and NIDILRR (90DPTB0025). Tara A. Austin, Olivia D. Cetin, Landon B. Lempke, Zhining Ou, Sreekanth Kamineni, Sarah L. Martindale, Maya E. O’Neil, David X. Cifu, and William C. Walker: declared no conflict of interest to disclose.

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