Carriers of genetic variant with head trauma, PTSD at increased risk of Alzheimer’s

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Results from a recent study showed that carriers of the apolipoprotein E (ε4) variant with post-traumatic stress disorder (PTSD) and traumatic brain injury (TBI) had an increased risk of Alzhiemer's disease and other related dementias (ADRD).

The study, published in the journal, Alzheimer’s & Dementia, was led by Mark Logue, PhD, a statistician in the National Center for PTSD at the VA Boston Healthcare System. For his investigation, Logue and a team of researchers sought to better understand the association between dementia, PTSD, TBI, and genetics.

Researchers studied the impact of ε4, a variant linked to dementia, on ADRD risk of veterans with PTSD and TBI. Data on the study’s subjects were collected from the Million Veteran Program (MVP), which included veteran cohorts of European ancestry and African ancestry. Using a mathematical model, Logue and his team observed interactions between the ε4 variant, PTSD, and TBI.

According to the study, scientists found an increased dementia risk due to PTSD and TBI in veterans of European decent who carried the ε4 variant. In veterans with African ancestry, the impact of PTSD did not appear to be changed by the ε4 variant. The interaction between TBI and the ε4 variant in veteran of African ancestry, however, was even stronger than those with European ancestry.

“These additive interactions indicate that ADRD prevalence associated with PTSD and TBI increased with the number of inherited APOE ε4 alleles,” Logue and his colleagues wrote. “PTSD and TBI history will be an important part of interpreting the results of ADRD genetic testing and doing accurate ADRD risk assessment.”

To Logue, the study’s results indicate a clear link between PTSD and TBI and dementia risk, suggesting that calculating dementia risk should go beyond age and genetics tests.

“In Veterans, a history of head injuries and PTSD can also make a large difference in dementia risk, so using that information will allow for more accurate measurement of the chances of developing dementia,” said Logue in a statement.