Clinical Pathology Abstracts

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Correspondence: Dr. Michael A. Mazzeffi at mmazzeffi@som.umaryland.edu

Mild TBI and risk of Parkinson disease: a chronic effects of neurotrauma consortium study

Mild traumatic brain injury, or concussion, affects approximately 42 million people worldwide each year. Among the groups most impacted by mild traumatic brain injury (mTBI) are athletes, military personnel, and the elderly. Long-lasting neurobehavioral consequences of mTBI include several psychiatric and neurodegenerative diseases. The Institute of Medicine has concluded that there is evidence to associate moderate to severe TBI with a clinical diagnosis of Parkinson disease. The authors investigated the risk of Parkinson disease after TBI or mTBI among patients in the Veterans Health Administration (VHA) database. They conducted a retrospective cohort study of 325,870 patients from October 2002 to September 2014 using the database. The authors age-matched 1:1 patients with a TBI diagnosis to a random sample of patients without TBI. All patients were 18 years or older and did not have Parkinson disease or dementia at baseline. TBI severity was defined as mild versus moderate-severe. Compared to patients without TBI, those with it were more likely to be diagnosed with Parkinson disease (hazard ratio, 0.58 versus 0.31 percent). TBI severity analysis also showed that patients with mTBI were more likely to be diagnosed with Parkinson disease than controls without TBI (hazard ratio, 0.47 versus 0.31 percent). The authors concluded that prior TBI was associated with an increased risk of being diagnosed with Parkinson disease during a 12-year follow-up and associated with a two-year earlier age of diagnosis of the disease. These data may contribute to understanding the association of TBI and Parkinson disease and the need to identify modifiable risk factors. The study focuses on the importance of this association for active-duty military and veteran populations, and it may have implications for athletes and other civilians as well.

Gardner RC, Byers AL, Barnes DE, et al. Mild TBI and risk of Parkinson disease: a chronic effects of neurotrauma consortium study. Neurol. 2018. doi:10.1212/WNL.​0000000000005522.

Correspondence: Dr. Raquel C. Gardner at raquel.gardner@ucsf.edun