Brain Injury Link to Alzheimer’s⁢ in Veterans Explored

⁤ Updated June 14,‍ 2025

A new study suggests a possible connection between mild traumatic brain injury (mTBI) and Alzheimer’s disease in U.S. veterans.Researchers at the University of Washington School of Medicine and VA Puget Sound Health Care System found that veterans exposed to explosive blasts, resulting in mTBI, exhibited changes in cerebrospinal fluid proteins. These changes are often observed in individuals who later develop Alzheimer’s.

The research, published in Neurology, analyzed spinal fluid from 51 veterans of⁣ the Afghanistan and Iraq ‍wars, each with a history of mTBI from blast exposure. The veterans had experienced an average of 20 blast injuries. These samples were compared to those of 85 veterans and civilians without TBI.

For the study, a TBI was defined as an ⁤alteration or loss of consciousness due to a blast. ⁣The injuries were ⁢classified as mild if the loss ⁢of consciousness lasted no more than 30 minutes and⁤ standard MRI or CT scans showed no brain ‍damage. Such an injury is considered equivalent to a concussion.The study focused on the levels of⁤ specific proteins in the cerebrospinal fluid, including alpha-beta amyloid 40 ⁣and 42 (Aβ40, Aβ42), key components of amyloid plaques found in Alzheimer’s patients, and versions of the tau protein.

Typically, Alzheimer’s disease is associated with decreased levels of alpha-beta amyloid proteins in spinal fluid, as ⁣these proteins are believed to deposit in amyloid plaques within the brain. Conversely, tau protein levels tend to increase as the disease progresses and brain cells die. The study revealed that veterans with mTBI, in their late 40s and 50s, had lower levels of beta-amyloid proteins compared to the control group. Abnormal tau protein levels ⁢were also observed in older veterans with mTBI. ⁢Normally, tau levels increase with age, but in these veterans, the ‍levels remained relatively stable, suggesting a potential⁢ disruption ⁤in the brain’s clearance‍ system.

Furthermore, lower levels of beta-amyloid 42⁢ in older veterans with mTBI correlated⁣ with poorer performance on cognitive tests assessing ⁤verbal memory and fluency. According to Dr. Elaine Peskind,‍ a research professor of psychiatry at ⁤UW ‍and director of the VA’s Northwest Mental Illness Research, Education, and Clinical Center, the⁤ decline in ‍beta-amyloid 42 is particularly concerning. ⁣”A decline in beta-amyloid 42⁢ is the earliest detectable change due to Alzheimer’s that ⁣can be found in a cognitively normal person,” Peskind said. “The change can appear ⁢as much as 20 years before symptoms.”

⁣ “While our research does not prove that veterans who experienced‍ these injuries will develop Alzheimer’s disease, it raises the possibility that they might potentially be on a pathway leading to dementia,” said Dr. Ge Li, associate professor of psychiatry and behavioral sciences at UW Medicine.

What’s next

Peskind and her colleagues hypothesize that blast-related damage to the glymphatic system, which facilitates fluid ⁣flow and waste removal in the brain, ⁢might potentially be responsible for these protein changes. ⁤With funding from the National Institute of Neurological ⁣Diseases ⁣and Stroke, they are continuing to investigate ⁢the regulation and function of this system in veterans⁢ with mTBI.