SEX, MILITARY-RELATED RISK FACTORS, AND DEMENTIA

By: Melissa Tanner, Ph.D.

As the country’s population ages, the number of veterans over the age of 65 increases. According to the 2017 U.S. Census, veterans comprise 33.72% of American men aged 65 to 74 and 47.42% of American men aged 75 years and over. While women only represent 9% of all veterans in the U.S., 30% of American women who are veterans are over 55 years old. This means that the U.S. has a large cross-section of older adult veterans of both sexes. The concept of dementia as a public health priority is gaining momentum, but it is important that we do not lose sight of older adult veterans as we explore strategies for prevention and treatment, particularly because military-related factors may place veterans at a higher risk of developing dementia.

Those who serve in the military face a unique set of exposures that, unfortunately, have been linked to an increased risk for a host of mental disorders, including depression, post-traumatic stress disorder (PTSD), and traumatic brain injuries (TBI). The rate of depression for those who serve in the military is 5 times higher than the rate for civilians, and the rate of PTSD is 15 times higher (Hill & Barnett, 2014). The difference in prevalence of TBI is more difficult to pinpoint, as TBI can be defined in different ways depending on the level of severity. However, it is clear that veterans are more likely to be exposed to concussions and combat blast injuries, which lead to TBI (McKee & Robinson, 2014). Troublingly, each of these disorders is associated with an increased risk of dementia. Veterans diagnosed with dysthymia or depression are twice as likely to develop dementia as those without dysthymia or depression, and the risk of developing dementia is also doubled in veterans with PTSD (Byers et. al., 2012; Yaffe et. al, 2010). In one retrospective cohort study of older adult veterans, TBI were associated with a 60% increase in risk of developing dementia over a 9-year follow-up period (Snyder et. al., 2018). Unfortunately, female veterans are under-represented in these studies, even though women with dementia outnumber men with dementia by a ratio of 2:1, and women are more likely to develop both depression and PTSD.

Recognizing the need to explore dementia- and military-related risk factors for female veterans, a new study published in the January 2019 issue of Neurology followed 109,140 female veterans receiving care at a Veterans Health Administration medical center (Yaffe et. al., 2019). The average age of the cohort was 69. Results revealed that female veterans with PTSD were about 80% more likely to develop dementia than female veterans who did not have PTSD. Female veterans with depression were about 70% more likely to develop dementia than female veterans who did not have depression. Lastly, female veterans with TBI were about 50% more likely to develop dementia than female veterans who did not have TBI. Given methodological differences between this study and those cited earlier, it is difficult to isolate sex differences in risk of developing dementia for veterans suffering from depression, PTSD, or TBI. However, it is clear for both sexes that having any of these conditions increases the likelihood that a veteran will develop dementia.

These results highlight the need for increased mental health screening for veterans of both sexes. They also point to the need for mental health treatment, not only to maximize veterans’ psychological functioning but to preserve the health of their aging brains. Lastly, shining a light on specific dementia risk factors for veterans points to the need for education targeted to this population. The BCAT® Research Center developed the ENRICH® public health initiative as a general set of guidelines for modifiable habits to pave the way for brain-healthy aging. Included in the ENRICH® acronym is a recommendation to seek treatment for depression and other mood symptoms. This is particularly relevant for veterans, who are at heightened risk for both mental health issues and dementia. Given this heightened risk, ENRICH® has the potential to have a profound impact on this population. Learn more about the ENRICH® initiative here (www.enrichvisits.com), and please share with the veterans in your life!