Hazard Ratio and Repeat Injury for Dementia in Patients with and Without a History of Traumatic Brain Injury

The impact of traumatic brain injury (TBI) on the pathogenic hazard ratio (HR) for dementia patients is still controversial. Some studies have supported the association between TBI and dementia, especially for Alzheimer's disease, and our study determined that the HR of dementia patients with and without a history of TBI or repeated TBI (RTBI). We determined the HR for dementia patients with a diagnosis of TBI (n = 12931) and a comparative cohort with age- and gender-matched controls (n = 51724) during 2004-2005, using Taiwan's National Health Insurance Research Database. The adjusted HR (HR = 3.21) for dementia patients with TBI showed that they were more likely to develop dementia than the comparison cohort. The HR for dementia patients with RTBI was increased to 3.62. The results of this large-scale study suggested that TBI increases dementia risk. Future studies using animal models and epidemiological databases could elucidate medical and biological mechanisms linking TBI and the development of dementia.