Sex‐specific incident dementia in patients with central nervous system trauma

Abstract

Introduction Despite evidence that central nervous system (CNS) trauma, including traumatic brain injury and spinal cord injury, can cause sustained neurocognitive impairment, it remains unclear whether trauma-related variables are associated with incident dementia independently of other known risk factors. Methods All adults without dementia entering the health-care system with diagnoses of CNS trauma were examined for occurrence of dementia. All trauma-related variables were examined as predictors in sex-specific Cox regression models, controlling for other known risk factors. Results Over a median follow-up of 52 months, 32,834 of 712,708 patients (4.6%) developed dementia. Traumatic brain injury severity and spinal cord injury interacted with age to influence dementia onset; women were at a greater risk of developing dementia earlier than men, all other factors being equal. Discussion Risk stratification of patients with CNS trauma by sex is vital in identifying those most likely to develop dementia and in understanding the course and modifying factors.

The Impact of a Comorbid Spinal Cord Injury on Cognitive Outcomes of Male and Female Patients with Traumatic Brain Injury

“…To better understand cognitive impairments stemming from TBI, a number of cohort studies identified groups at risk of post‐injury cognitive decline 7 and reported worse cognitive outcomes in those with lower socioeconomic standing, system level comorbidities, more severe TBI, or concussive nature of injury. A recent longitudinal study confirmed these risk factors, and also found that comorbid spinal cord injury (SCI) increases the risk of incident dementia in both men and women with TBI across injury severities, even after controlling for depression, sleep disorders, and other previously noted risk factors 8 . Spinal cord injury in TBI is expected to disrupt conduit functions of tracts going to and from higher centers in a variety of ways, manifesting in different clinical presentations, heterogeneous abnormalities, including those concerning cognition.…”

“…All adult (≥18 years) Ontario residents who had received a diagnosis of CNS trauma 8 in an emergency department or acute care unit between April 1, 2002 and March 31, 2016 were identified using previously validated case definitions based on health administrative data 29,30 . The date of the first TBI diagnosis following open or closed injury (based on whether there was breach of the integrity of the cranial vault) was defined as the index date that marked the beginning of the study period for each patient.…”

“…To account for multiple comorbidities in both exposed and unexposed patients, we generated binary variables indicating the presence of 32 comorbid conditions as defined in the CCI in both groups, excluding dementia‐related conditions, to be tested separately, but adding a category of sleep disorders, which have been shown to be independently associated with dementia onset in TBI patients and patients with a dual diagnosis 8 …”

“…To account for multiple comorbidities in both exposed and unexposed patients, we generated binary variables indicating the presence of 32 comorbid conditions as defined in the CCI in both groups, excluding dementiarelated conditions, to be tested separately, but adding a category of sleep disorders, which have been shown to be independently associated with dementia onset in TBI patients and patients with a dual diagnosis. 8 The main variable of interest in the modeling process was the presence of SCI comorbidity; however, additional models were run with SCI completeness and SCI level, due to the significant differences observed between different severities and levels of SCI injuries. To account for possible misclassification bias from using SCI case definition codes with unspecified completeness of injury, we combined complete and incomplete SCI because of the small sample size in both, to examine the effect of a more significant versus unspecified SCI.…”

“…A recent longitudinal study confirmed these risk factors, and also found that comorbid spinal cord injury (SCI) increases the risk of incident dementia in both men and women with TBI across injury severities, even after controlling for depression, sleep disorders, and other previously noted risk factors. 8 Spinal cord injury in TBI is expected to disrupt conduit functions of tracts going to and from higher centers in a variety of ways, manifesting in different clinical presentations, heterogeneous abnormalities, including those concerning cognition. The spinal cord is also part of the autonomic nervous system (ANS), where injury to the parasympathetic craniosacral outflow to the thoracic, abdominal, and pelvic viscera is expected to manifest in abnormalities of the heartbeat, blood diversion, and in a general sense, impact the body's energy regulation, initiating a cascade of adverse effects associated with ANS dysfunction.…”