Bicycle Helmet Safety Institute
The Helmet Update by email
Volume 18, #7 - October 31, 2000
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Study Suggests Head Injury Increases Risk of Later Problems
A study published in the October issue of the journal
Neurology by the American Academy of Neurology showed a much
higher incidence of Alzheimer's disease (AD) and other dementias late in life among WW II veterans who had suffered head
injuries during their military service. Although similar results have emerged in other studies, this one took advantage
of military records rather than relying on patient recall, increasing accuracy. The increased risk varied with the
severity of the injury, rising to four times normal in those who had suffered severe injuries. The study results for mild
head injury were "inconclusive." The risk of dementia increased even when a head injury was sustained 40 to 50 years
earlier.
The authors conclude "The veterans in this study sustained head injuries in early adult life. Their risk of dementia 50
years later suggests that pathogenesis of the degenerative dementias may trace to origins decades before the appearance
of clinical symptoms. This result is consistent with the perspective that AD is a chronic disease that unfolds over many
decades, with an extended latent phase as well as a prodromal stage (progressive "age-related cognitive decline") and the
stage of fully expressed dementia." The authors reportedly have added in press interviews the caution that the wartime
injuries studied may not be typical of injuries sustained in a bicycle crash. This study still has implications for any
participant in an activity where head injury is a problem.
The study is titled
"Documented Head Injury in Early Adulthood and
Risk of Alzheimer's Disease and Other Dementias," by Plassman, et. al.
The Helmet Update - Bicycle Helmet Safety Institute
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