Associations of Traumatic Brain Injury With Dysautonomia in a Cohort of Community Dwelling Adults

Traumatic brain injuries (TBI) are a leading cause of long-term disability and mortality, particularly among community dwelling adults. Globally, approximately 69 million individuals seek medical care for a TBI each year, including 2.8 million cases in the United States. Middle aged and older adults are disproportionally affected, with over 102,000 hospitalizations and nearly 20,000 deaths annually, attributed to TBI. The prevalence of TBI related complications rises sharply after the age of 75. Autonomic Nervous System (ANS) dysfunction or dysautonomia, categorized by Orthostatic Hypotension and low heart rate variability (HRV), has been linked with head injuries. Still, little work has been done in establishing the short- and long-term relationships between dysautonomia and head injury in adult populations. Findings in the acute and chronic relationships between dysautonomia and head injuries remain inconsistent. This dissertation utilizes the Atherosclerosis Risk in Communities (ARIC) Cohort to determine whether prior TBI is independently associated with dysautonomia among community dwelling older adults, using cross-sectional and longitudinal analyses. Overall our findings do not suggest that prior head injury is an independent risk factor for dysautonomia, nor did we see statistically significant results in follow-up data with dysautonomia and risk of head injury. This work adds to the existing literature by providing the first population-based assessment of head injury and dysautonomia using a large, longitudinal cohort. This work highlights the needfor more nuanced mechanistic and temporal models to understand dysautonomia in the context of neurotrauma and aging.