July/August 2024

July/August 2024 Issue

Veterans and Dementia
By Jamie Santa Cruz
Today’s Geriatric Medicine
Vol. 17 No. 4 P. 16

Factors related to military service, such as traumatic brain injury and PTSD, put veterans at increased risk for dementia.

The number of US veterans living with dementia has surged in recent years. Close to half a million former service members have Alzheimer’s disease (AD),1 and new diagnoses are expected to continue growing rapidly over the next decade. The VA projects that the number of veterans with AD dementia alone (not including other dementias) will increase by as much as 8.4% by 2033.2

Although many veterans receive medical care through the VA, a large percentage do not. For that reason, it’s important for providers both inside and outside the VA to know the unique factors that put veterans at risk for dementia—and how to care for them in the event of a dementia diagnosis.

Why Are Veterans at High Risk?
Veterans develop dementia at approximately the same rates as the general population. The prevalence of dementia among veterans older than 65 is 10.1%, which is very similar to the prevalence of 10.5% in the general older than 65 population.

That said, the veteran population skews much older than the rest of the US population. The median age of male veterans in the US is 65,3 compared with a median age of 39 in the general population.4 This means that veterans make up a disproportionately large share of the total number of Americans living with dementia.

Veterans can have all of the same risk factors for dementia common in the general population, such as high blood pressure, diabetes, and lack of physical activity. However, they’re also vulnerable to several risk factors specifically related to military service. Among these are traumatic brain injury (TBI), PTSD, sleep disturbance and deprivation, and heavy alcohol use.

Risk Factor #1: TBI
TBI, a common injury among service members, can result from a variety of causes. Most military-related TBI stems from explosive blasts, such as from roadside bombs, artillery, or shells, but TBIs also can be caused by vehicle accidents or falls.

In a study of more than 180,000 older veterans, researchers found that those who had suffered TBI had a 60% higher risk of developing dementia compared with veterans who hadn’t experienced a TBI. Further, veterans with TBI developed dementia on average two years earlier than did those without TBI.5 A separate study of World War II veterans found that mild TBI didn’t increase risk of AD, but moderate TBI doubled the risk, and severe TBI quadrupled risk.6

It’s not clear exactly how TBI might mechanistically contribute to neurodegeneration. However, following a TBI, the human brain tends to show an accumulation of amyloid-beta, p-tau, alpha-synuclein, and TDP-43 proteins, which are the same proteins whose accumulation is characteristic of AD.7

Unfortunately, TBI is becoming more common among veterans. Most of the American veterans who are living with dementia served during the Vietnam War, in which only 12% of combat casualties were attributed to brain injuries.8 By contrast, as much as 23% of combat casualties among veterans of the wars in Iraq and Afghanistan were TBIs.8 Brain injuries were so common among veterans of Iraq and Afghanistan that the US Department of Defense has called TBI a “signature injury” of those wars.9 As veterans of these later wars age, their injuries are expected to cause a corresponding increase in the number of veterans living with dementia.

Risk Factor #2: PTSD
PTSD is more common in veterans than in the general population: up to 20% of veterans who fought in Iraq or Afghanistan since 2001 have experienced PTSD,10 compared with a lifetime prevalence of less than 7% in the general population.11

Although it might be natural to assume that veterans develop PTSD because of traumas they were exposed to in combat, the reality may be more complicated. American veterans report relatively high rates of both military and nonmilitary trauma, and some research shows that nonmilitary trauma prior to deployment predisposes soldiers to PTSD after deployment.12-15

In turn, people with PTSD face up to double the risk of AD and other dementias.16,17 It’s not clear exactly why this is. However, there’s some evidence (albeit controversial) that veterans with PTSD perform more poorly on tests of cognitive function than do those without PTSD. This could mean that PTSD results in lower cognitive reserve, which in turn increases dementia risk.16

Another possibility is that chronic stress damages the hippocampus, which is central to memory and learning.16 Several studies have shown that PTSD is associated with changes in the hippocampus, including decreased concentrations of the neuronal marker N-acetyl aspartate, as well as reduced hippocampal volumes.18,19 Some researchers thus suggest that PTSD leads to dementia by causing hippocampal atrophy.

Still other studies suggest that PTSD may cause dementia by increasing cortisol levels and inflammation, both of which are linked to dementia.16

Importantly, the relationship between dementia and PTSD seems to be bidirectional. PTSD increases the risk of dementia, but dementia may also increase the risk of PTSD or PTSD symptoms. Indeed, a number of studies now show that dementia onset is linked to delayed emergence, reemergence, and intensification of PTSD symptoms.20

“We really don’t know why,” says Kimberly Ritchie, PhD, an assistant professor at the Trent/Fleming School of Nursing at Trent University in Ontario, Canada. “There is some thought that maybe it has to do with the neurodegeneration that happens with dementia—that this neurodegeneration disinhibits the ability to suppress traumatic memories. Others think that someone with dementia might not be as able to avoid triggers. Maybe most veterans would avoid news stories about war, or TV shows. But if you live in a long term care environment, those things are hard to avoid.”

While dementia can intensify PTSD symptoms, there’s also preliminary evidence that a history of PTSD can intensify symptoms of dementia. According to Ritchie, veterans with dementia typically exhibit the same behaviors—agitation, anxiety, repetitive vocalizations, wandering, and so on—as do nonveterans, but early research suggests these symptoms may be more severe in veterans with a past history of trauma, compared with individuals without a history of trauma.21

Significantly, the risk factors of TBI and PTSD overlap among veterans: as many as half of veterans with combat-related TBI also experience PTSD.22-24

Risk Factor #3: Sleep Disturbance or Deprivation
Sleep problems are common among military personnel and veterans.7 One study of service members deployed in Iraq found that 72% of participants routinely slept six hours or less, qualifying them for short sleep duration.25 Another study of service members in the US Air Force found that 75% reported worse sleep quality after deployment compared with before.26 Yet another study of veterans who served after 9/11 found that 57.2% met the criteria for insomnia disorder.27

Problems with sleep appear to contribute to dementia risk. In one civilian study, fragmented sleep was associated with a greater risk of AD; those in the 90th percentile on measures of sleep fragmentation had a 50% increased risk for AD compared with those in the 10th percentile.28 In a similar vein, a 2018 meta-analysis found that individuals with sleep disturbances had a 19% higher risk of dementia than did those without.29

Although most research so far has focused on civilians, there’s been at least one study of sleep disturbance in veterans and risk of dementia. This study—a retrospective cohort design that enrolled nearly 180,000 male veterans from the VA—found that veterans older than the age of 55 who experienced sleep disturbances were at a 27% greater risk of dementia than were those who didn’t.30

The exact mechanisms for how sleep loss and disturbance might cause dementia aren’t well established, but some research suggests that poor sleep causes neuronal damage that may lead to cognitive decline.31,32 In addition, slow wave sleep seems to be important in clearing amyloid beta from the brain, and sleep loss or disturbance may thus result in the buildup of amyloid beta.33,34

Importantly, there’s an overlap between TBI and PTSD and sleep problems among veterans.7 One study of veterans with TBI found that 46% of participants also had a sleep disorder,35 and other research suggests that as many as 50% of veterans with TBI have insomnia symptoms.36,37 Similarly, a study of Vietnam veterans reported that those with PTSD had greater difficulty falling asleep and staying asleep, and they also had a higher incidence of nightmares, compared with those without PTSD.38 Other research in civilians confirms that individuals with PTSD are at much higher risk of insomnia than are those without.39

Understanding the connection between TBI, PTSD, and sleep is critical, because it suggests that sleep interventions among veterans with TBI or PTSD early on after their return from deployment could help lower their dementia risk later in life.7

Risk Factor #4: Problematic Alcohol Use
Use of illicit drugs is relatively low among active-duty personnel, and cigarette smoking and misuse of prescription drugs have fallen.40 However, rates of binge drinking and alcohol use disorder are comparatively high among both active-duty military personnel and veterans, compared with civilians.40,41 Heavy alcohol consumption has long been a part of military culture,42 and a 2023 RAND report found that in every age group, the prevalence of binge drinking was higher among veterans than among civilians. Rates of alcohol use disorder were also higher among veterans: in the 65+ age group, for example, 2.7% of veterans reported alcohol use disorder, compared with just 1.5 of nonveterans.43

“There is a stigma with this, and I don’t want to suggest that all veterans have substance use problems,” according to Thomas Bayer, an assistant professor of medicine at Brown University Alpert Medical School, a health services researcher, and an attending physician at the Providence VA Medical Center. At the same time, “we know that some veterans have substance use problems.”

Although some studies suggest that light-to-moderate alcohol use is protective against dementia, current research—mostly in civilian populations—indicates that heavy alcohol use is a risk factor for dementia.44 For instance, a study of civil service workers in England found that participants who drank more than 14 drink units per week had a 40% higher risk of dementia compared with those who drank between one and 14 drink units per week.45 Similarly, a 2019 scoping review found that heavy alcohol consumption is associated with changes in brain structures and cognitive impairments and is linked to greater likelihood of dementia.46 Although research in veterans is quite limited, one study found that alcohol use disorder among female US veterans 55 years and older was linked to a more than threefold increase of dementia.47

As with sleep problems, problematic alcohol use may represent an important area for intervention to help reduce the risk of dementia among veterans. The good news is that veterans appear disposed to seek such help: according to research from the RAND Corporation, in every age group, veterans are more likely than nonveterans to seek alcohol/drug treatment.43

Expert Guidance for Clinicians
1. Don’t stereotype. “I’m very careful about generalizing about veterans, because it’s easy for the public to pigeon-hole veterans as people who all have PTSD or substance abuse problems,” Bayer says. “A lot of veterans don’t have any of those problems.” At the same time, he says, it’s important to acknowledge the percentage of veterans who do have conditions such as PTSD—and it’s important to provide appropriate treatment.

2. Ask patients if they’ve served in the military. Since this is a factor that can affect a patient’s needs, physicians should make military service a part of their patient history questionnaires, Bayer says.

3. With younger veterans who don’t have dementia, encourage lifestyle behaviors that can reduce their future dementia risk. “There is a growing body of research to suggest adopting and maintaining healthy lifestyle behaviors, including healthy eating, exercising regularly, not smoking and staying cognitively engaged may help reduce the risk of cognitive decline,” says Sam Fazio, PhD, senior director, quality care and psychosocial research at the Alzheimer’s Association. “The Lancet Commission on dementia prevention, intervention and care suggests that addressing modifiable risk factors might prevent or delay up to 40% of dementia cases.”48

4. Work for early diagnosis. For veterans and nonveterans alike, “Early detection and diagnosis of Alzheimer’s and other dementia is critically important and offers the best opportunity for care, management, and treatment of cognitive decline,” Fazio says. New FDA-approved treatments offer the potential to slow the progression of Alzheimer’s, Fazio adds, “but they are only available to individuals in the early stage of the disease.”

For newly diagnosed veterans, Fazio recommends the Alzheimer’s Association’s dedicated webpage for veterans: www.alz.org/help-support/resources/veterans-dementia. This page contains a robust list of resources for veterans and their caregivers from both the Alzheimer’s Association and the VA health care system.

5. Ask veterans about trauma history, both during and outside of their military service. For veterans who don’t have dementia, PTSD is an intervention target that could help reduce the risk of dementia later on, and for veterans who have already been diagnosed, a history of trauma can affect their experience of dementia and the kind of care they need.

“Even if the veteran indicates that they haven’t experienced trauma, we know that veterans don’t always like to talk about past trauma, and they may not have talked about it before, because they don’t want to traumatize other people,” Ritchie says.

For veterans with dementia who also have trauma history, it is important to distinguish which symptoms may be arising from dementia and which are symptoms of trauma.49 Ritchie’s research also suggests that it’s very important to establish trust and cultivate a sense of safety. “Focus on a routine and relational approach. Lower their sense of fear.” Such an approach can help reduce symptoms of dementia that may be exacerbated by trauma.49

In addition, care providers should eliminate trauma triggers as much as possible. “From my own experience, the triggers can be very different from person to person. You have to get to know the person and the family and find out what might have been triggering them in the past,” Ritchie says.

One final suggestion: guide veterans toward the VA. “If you suspect a patient has dementia (or any kind of long-term disability), make sure that person is engaged with VA care,” Bayer says.

A main reason for this, he adds, is that the VA has programs to support patients with dementia that would be hard to find in the private sector. For example, the VA runs its own long term care centers, called community living centers. It has long emphasized a multidisciplinary model of care, including and especially for veterans with dementia, and it’s developed a series of novel caregiver support and training programs, as well as care-integration programs, that have the potential to significantly improve the lives of veterans.

“We don’t want patients to wait until they have a long-term disability to get engaged with VA care, but if they have waited, get them engaged,” Bayer says.

It might not be possible to prevent dementia arising from military service. But providers can at least be alert for risk factors, treat modifiable risk factors, and connect veterans who have been diagnosed with dementia with the best care possible.

— Jamie Santa Cruz is a freelance writer based in Englewood, Colorado.

References
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