Category: Brain Injury; Lifestyle Medicine; Cross-Cutting
To examine the relationship between diagnosed sleep disorder and incident dementia in a cohort of adult men and women with traumatic brain injury (TBI).
Design : A retrospective cohort study using population based provincial health administrative data.
Setting : Emergency or acute care department in the province of Ontario, Canada.
Participants (or Animals, Specimens, Cadavers) :
All adults without previous dementia diagnoses entering the emergency or acute care department between 2003 and 2013 with a diagnosis of TBI with or without comorbid spinal cord injury (SCI), were followed through until May 2016, to examine the occurrence of Alzheimer's disease.
Interventions : Not applicable.
Main Outcome Measure(s) : Incident hospitalized Alzheimer's disease. Cox regressions were used to investigate the relationship between presence of a diagnosed sleep disorder in persons with TBI and incident hospitalized Alzheimer's disease.
In total, 712,708 persons with TBI of all severity, with or without comorbid SCI, free of dementia at the injury date, were studied. Their median age was 44 years, 59% were men. Over a median follow-up of 52 months (interquartile range, 19-86 months), 5,083 patients developed Alzheimer’s disease. Controlling for sex, age, income level, TBI severity, SCI comorbidity, disorders of circulatory and vascular systems, tobacco smoking, depression, and sensory impairments, a diagnosed sleep disorder was a significant predictor of incident Alzheimer’s disease: HR 1.328 [95% CI, 1.072-1.645]. When results were stratified by biological sex, the sleep disorder association with Alzheimer’s disease remained significant in women only: HR 1.483 [95% CI, 1.115-1.972]; in men: HR 1.161 [95% CI, 0.840-1.606].
Results highlight a novel marker of incident Alzheimer's disease in patients with TBI – sleep disorder. In women with TBI alone or with comorbid SCI, diagnosed sleep disorder was independently associated with a 48% increased hazard of incident Alzheimer's disease. Further study to understand the sex-specific relationship between sleep disorders and Alzheimer's disease timely.
Tatyana Mollayeva– Post Doctoral Fellow, Toronto Rehab-UHN, Toronto, Ontario
Mackenzie Hurst– Research Analyst, Toronto Rehabilitation Institute (TRI) - University Health Network (UHN), Toronto, Ontario
Michael Escobar– Professor, Dalla Lana School of Public Health, Toronto, Ontario
Angela Colantonio– Professor and Director, University of Toronto, Toronto, Ontario