Members of the military often come to find that their past experience in the armed forces defines much of their lives moving forward. Veteran health and wellness are no exception to that.
Research continues to uncover not only that military veterans experience higher rates of dementia, but that this increased prevalence is likely related to their time in the service.
Risk Factors
It turns out those who put themselves in danger for others while serving in the military are not only putting themselves at risk while serving, but actually put themselves at greater risk for neurodegeneration later in life. There are a number of risk factors which put service members uniquely at risk, which include head injury, Post-Traumatic Stress Disorder and/or Depression, and exposure to environmental toxins.
Head injury
You may recall from one of our recent blogs that head injury is associated with not only neurodegenerative disease itself, but also with earlier onset, increased impairment, increased mortality and Alzheimer’s Disease-type pathological changes (Abner, et al., 2014).
If you have not read that article, please take a moment to as it will only inform your further reading:
Service members are uniquely at risk for this type of injury, and the incidence of traumatic brain injury (TBI) in the military has increased since 2000, with a peak in 2011 and 2012 (Cohen Veterans Bioscience, 2020). TBI in combat can result from motor vehicle collisions and rollover accidents, penetrating injuries from a bullet, shrapnel, or other debris, and from blast injuries, in which the force of the pressure wave emitted from the blast can cause significant damage to the brain (Air Force Center for Excellence of Medical Multimedia 2019). Between 2010 and 2015 alone, 320,000 service members incurred a TBI, and approximately 8,000 of those suffered a TBI which was medically classified as “server to penetrating.” Additionally, 80 percent of TBI cases in the military actually occur in non-deployed or training settings (Cohen Veterans Bioscience, 2020).
This high incidence of TBI also trickles over into the vetran community, a survey of 770,000 veterans revealed that nearly 60,000 were evaluated for or had been or were being treated for a TBI-related condition (Cohen Veterans Bioscience, 2020). Additionally, veterans may be quite likely to sustain TBIs throughout their lifespan even once returning to civilian life. Data shows that the largest increase in veteran TBI’s occur as the veterans enter into their 70s and 80s and are often related to falls and result in high levels of disability. Whatsmore, veterans with a TBI are 60 percent more likely to develop AD or another form of dementia (Defense and Veterans Brain Injury Center, 2020).
Additionally, military service members with a history of mild TBI are at an increased risk for developing post-traumatic stress (PTS), which just so happens to be the second risk factor which may make members of the service uniquely likely to experience neurodegenerative disease.
Post Traumatic Stress Disorder and Depression
Post-Traumatic Stress Disorder (PTSD) is a fear based disorder characterized by intrusion symptoms, (such as flashbacks and nightmares) avoidance of traumatic stimuli, alterations in cognition and mood, and alterations in arousal and reactivity as a result of exposure to a traumatic event or stressor. PTSD is one of the most common diagnoses assigned to members of the armed forces upon returning from combat. Additionally, PTSD is documented as being associated with a decline in cognitive performance (Maryniak, 2015).
TBI and PTSD are both signature injuries of time spent in the military, and are both linked to increased risk for the development of dementia. This phenomenon has been observed not only in armed forces involved in the wars in Iraq and Afghanistan, but also in those who returned from Vietnam (Weiner et al. 2013, 2017.)
In fact, among U.S. Army infantry soldiers who returned from Iraq, 43.9 percent of those who reported a TBI with loss of consciousness also exhibited symptoms of Post Traumatic Stress, and an additional study found that up to a third of veterans overall with a probable TBI from their time in the service also met the criteria for probable PTSD (Defense and Veterans Brain Injury Center, 2020). Not only are TBI and PTSD signature injuries of military members and veterans, but they are often co-occurring risk factors.
Research conducted in the last 5 years shows that those veterans with PTSD are twice as likely to develop dementia as those without PTSD, and are up to four times as likely to develop dementia as a civilian (Shane, 2017).
Depression, which frequently also occurs alongside both TBI and PTSD, also adds to one’s risk of developing dementia. It turns out that the military and vetran community are no exception to this risk factor as well. One study which examined elderly female veterans (gender differences in dementia show women are more likely than men to develop the disease, and more information on gender differences in dementia can be found in the blog at this link: https://yoga4brainhealth.com/this-is-a-mans-world-gender-differences-in-the-prevalence-of-alzheimers-disease-by-aubree-kozie-edited-by-david-webster/) found that women who served who had military-related risk factors including TBI, PTSD, and depression were between 50 to 80 percent more likely to develop dementia than women without TBI, PTSD, or depression. More specifically, female veterans with multiple risk factors had more than two times the risk for developing dementia (Yaffe, et al., 2019).
Additional research has confirmed the association between increased risk for dementia and PTSD or Major Depressive Disorder (MDD) in not only civilian populations, but in military and veteran communities as well (Rafferty, Cawkill, Stevelink, Greenberg, & Greenberg, 2018).
More recently, research has gone past the association between PTSD and dementia in the process of uncovering exactly how these conditions are related. Studies of childhood and developmental cases of PTSD indicate that there may be a genetic link between Alzheimers and PTSD.
The working theory is that multiple risk factors for dementia eventually meet the body’s threshold to activate genes which contribute to the development of Alzheimer’s disease.
Researchers believe the gene responsible is the Formin 2 (Fmn2) gene. Mutations in this gene are associated with intellectual disability, and this gene is thought to be involved in actin cytoskeleton organization in the brain. The cytoskeleton is the structural element of a cell, which helps it take its shape and keeps its internal organization in place, like the skeleton of a cell. In mice who had their Fmn2 gene silenced, scientists observed not only PTSD pathology, but also an acceleration of memory-related cognitive decline. Post mortem examination of the brains of Alzheimer’s patients also revealed reduced Fmn2 expression. Thus aberrant gene expression may be the causal link between PTSD and dementia (Agís‐Balboa, et al. 2017). Future research may continue to reveal that other risk-factors for dementia operate through a similar genetic mechanism which alters the body’s physical expression, resulting in changes in pathology.
Toxin Exposure
Not only are members of the military exposed to dangerous and traumatic circumstances and experiences, they are often also exposed to toxins, some of which are and have historically been used for chemical warfare. While toxin exposure has always been a listed risk factor for the development of dementia even in the civilian population, the military and vetran community are more likely to come into contact with more rare and destructive chemicals and toxins.
For instance, the chemical agents notably known as “Agent Orange” is a defoliant that was used to thin dense tropical foliage during the Vietnam War from 1961-1971). Modern research in the past ten years has revealed that chemical exposure in veterans to toxins including Agent Orange, is associated with the development of type II diabetes, hypertension, heart disease and metabolic syndrome. Although they have found no definitive causation between exposure to the controversial herbicide and cognitive decline, each of the above listed health conditions is a risk factor for the development of dementia (Veitch, Friedl, & Weiner, 2013).
In evaluating even three of the major risk factors for dementia among military and vetran populations, it is clear to see that the likelihood of veterans developing some form of the disease is exponentially greater than for a civilian.
Conclusion
The department of Venteran’s affairs has reported that rates of enrollee’s with Alzheimer’s disease has doubled between 2004 and 2014, and more than 750,000 elderly veterans worldwide suffer from the disease or another form of dementia. This number is only expected to continue to rise. George Vradenburg, chairman of Us Against Alzheimer’s, the parent organization for the new group, reports, “This is a looming pandemic, and promises to be the health issue of the 21st century,” (Shane, 2017).
This reflection emphasizes not only the high risk for veterans, but also the need for veterans to engage this health issue of the century. Alzheimer’s and other forms of dementia can be effectively prevented or staved off by implementation of a brain healthy lifestyle.
It is important for veterans and their loved ones to know that past military experience should not define your future health. One cannot do anything about the past, but the future is in the capable hands of those who defend this country. Military members and veterans can protect and serve not only their country, but also their own wellbeing!
References:
Abner, E. L., Nelson, P. T., Schmitt, F. A., Browning, S. R., Fardo, D. W., Wan, L., … Kryscio, R. J. (2014). Self-reported head injury and risk of late-life impairment and AD pathology in an AD center cohort. Dementia and geriatric cognitive disorders, 37(5-6), 294–306. doi:10.1159/000355478
Air Force Center for Excellence of Medical Multimedia (2019). Common Causes: Military and Civilian TBI. CEMM Library. https://tbi.cemmlibrary.org/Mild-TBI-Concussion/Common-Causes-Military-and-Civilian-TBI
Defense and Veterans Brain Injury Center. (2020). TBI & the military. Defense and Veterans Brain Injury Center. https://dvbic.dcoe.mil/tbi-military
Cohen Veterans Bioscience. (2020). Traumatic Brain Injury. Cohen Veterans Bioscience. https://www.cohenveteransbioscience.org/traumatic-brain-injury/
Weiner, M. W., Friedl, K. E., Pacifico, A., Chapman, J. C., Jaffee, M. S., Little, D. M., … & Yaffe, K. (2013). Military risk factors for Alzheimer’s disease. Alzheimer’s & Dementia, 9(4), 445-451.
https://aanddjournal.net/article/S1552-5260(13)00132-5/fulltext
Weiner, M. W., Harvey, D., Hayes, J., Landau, S. M., Aisen, P. S., Petersen, R. C., … & Saykin, A. J. (2017). Effects of traumatic brain injury and posttraumatic stress disorder on development of Alzheimer’s disease in Vietnam veterans using the Alzheimer’s Disease Neuroimaging Initiative: preliminary report. Alzheimer’s & Dementia: Translational Research & Clinical Interventions, 3(2), 177-188.
Shane, L. (2017). Advocates warn war injuries could lead to Alzheimer’s Disease. Military Times.
Yaffe, K., Lwi, S. J., Hoang, T. D., Xia, F., Barnes, D. E., Maguen, S., & Peltz, C. B. (2019). Military-related risk factors in female veterans and risk of dementia. Neurology, 92(3), e205-e211.
https://n.neurology.org/content/92/3/e205.abstract
Rafferty, L. A., Cawkill, P. E., Stevelink, S. A. M., Greenberg, K., & Greenberg, N. (2018). Dementia, post-traumatic stress disorder and major depressive disorder: a review of the mental health risk factors for dementia in the military veteran population. Psychological medicine, 48(9), 1400-1409.
Veitch, D., Friedl, K., & Weiner, M. (2013). Military risk factors for cognitive decline, dementia and Alzheimer’s disease. Current Alzheimer Research, 10, 907-930.
Maryniak, K. (2015). PTSD and agent orange: The risk for dementia. AMN Healthcare.
https://www.rn.com/nursing-news/ptsd-and-agent-orange-the-risk-for-dementia/
Agís‐Balboa, R. C., Pinheiro, P. S., Rebola, N., Kerimoglu, C., Benito, E., Gertig, M., … & Jatzko, A. (2017). Formin 2 links neuropsychiatric phenotypes at young age to an increased risk for dementia. The EMBO journal, 36(19), 2815-2828.
