|Title||Prospective Investigation of Insomnia Symptoms and Sleep Duration as Risk Factors for Stroke Incidence and All-Cause Mortality in U.S Adult|
|Year of Publication||2023|
|Degree||Doctor of Philosophy|
|University||Virginia Commonwealth University|
Background and Objectives: Stroke is the second leading cause of death in the world. In the United States, on average, someone has a stroke every 40 seconds and someone dies as a result of stroke every 3.5 minutes. Identifying modifiable risk factors of stroke is therefore a public health priority. The purpose of this study was to investigate the extent to which insomnia symptoms and sleep duration contribute to stroke incidence, all-cause mortality, and explore potential causal pathways.
Methods: The Health and Retirement Study (HRS) and the REasons for Geographic And Racial Differences in Stroke (REGARDS) study were used as the data sources. While the exposure variables were insomnia symptoms and sleep duration, the outcome variables were stroke incidence and all-cause mortality. Insomnia symptoms were derived from self-reported sleep-related factors including difficulty initiating sleep, difficulty maintaining sleep, waking up too early, and nonrestorative sleep. Sleep duration was categorized into short sleep (≤6 hours), adequate sleep (7.0-8.9 hours), and long sleep (≥9 hours). Cox proportional hazards regression models were employed to investigate the association between insomnia symptoms, sleep duration and the risk of stroke incidence and all-cause mortality.
Results: Compared to subjects with no insomnia symptoms, those with insomnia symptom scores ranging from 1 to 4 and 5 to 8 were associated with increased risk of stroke (hazard ratio (HR) = 1.16, 95% confidence interval (CI): 1.02, 1.33) and (HR =1.51, 95% CI: 1.29, 1.77), respectively, suggesting a dose-response relationship. In stroke survivors, insomnia symptom scores ranging from 5 to 8 were associated with increased risk of all-cause mortality among males less than 65 years old and males 65 years and over (HR=2.24, 95% CI: 1.09, 4.58 and HR=1.26, 95%: 0.97, 1.65, respectively) compared to those with no insomnia symptoms. Stroke survivors with long sleep (≥9 hours) were at increased risk of all-cause mortality (HR=1.53, 95% CI=1.03, 2.29) compared to stroke survivors with adequate sleep (7.0-8.9 hours). However, short sleep (≤6 hours) was not associated with an increased risk of all-cause mortality (HR=1.36, 95% CI=0.93, 2.02).
Discussion: Insomnia symptoms were associated with an increased risk of first ever stroke in the general population and an increased risk of all-cause mortality among stroke survivors while long sleep duration was associated with increased risk of all-cause mortality among stroke survivors. Increased awareness and better management of insomnia symptoms may contribute to the prevention of stroke occurrence and premature death.