Associations between traumatic brain injury and the prevalence of Alzheimer's disease dementia and behavioral and psychological symptoms of dementia: A retrospective cohort study.

BACKGROUND

Traumatic brain injury is an environmental risk factor that may accelerate the progression of Alzheimer's disease and behavioral and psychological symptoms of dementia in patients with mild cognitive impairment.

OBJECTIVES

To investigate whether traumatic brain injury in patients with mild cognitive impairment is associated with an increased risk of progression to Alzheimer's disease dementia and behavioral and psychological symptoms of dementia.

DESIGN

A retrospective cohort study using the Korean National Health Insurance Service database.

SETTING

National-level health data covering healthcare utilization, diagnoses, prescriptions, and procedures in South Korea from January 2012 to December 2021.

PARTICIPANTS

Patients diagnosed with mild cognitive impairment between January 1, 2013, and December 31, 2016, were followed until Alzheimer's disease dementia diagnosis, behavioral and psychological symptoms of dementia occurrence, death, or December 31, 2021. These patients were classified into two groups according to the presence of traumatic brain injury during the follow-up period.

MEASUREMENTS: Age at the time of mild cognitive impairment diagnosis, sex, income level, the presence of several chronic conditions, presence of traumatic brain injury, progression of Alzheimer's disease dementia, and behavioral and psychological symptoms of dementia

RESULTS

We assessed 452,718 patients (mean age: 67.16 years). Traumatic brain injury was significantly associated with an increased risk of Alzheimer's disease dementia progression (hazard ratio = 1.252, 95 % confidence interval: 1.206-1.301), particularly among patients aged <65 years (hazard ratio = 1.560, 95 % confidence interval: 1.391-1.749), and was linked to a higher risk of behavioral and psychological symptoms of dementia following Alzheimer's disease dementia diagnosis (hazard ratio = 1.300, 95 % confidence interval: 1.181-1.431).

CONCLUSIONS

Our results underscore the importance of traumatic brain injury prevention in patients with mild cognitive impairment for mitigating the progression and neuropsychiatric complications of Alzheimer's disease.