Variety of Sleep Impairments Associated With Acute Stroke
A derived Obstructive Sleep Apnea score of 2-3 and cumulative sleep symptoms were found to be associated with a significantly higher odds of acute stroke.
Christine E. McCarthy, MB, BCh, BAO, MSc
Recently published findings from the INTERSTROKE study identified a significant association between sleep impairments and risk of acute stroke, with this risk increased by short and long sleep duration, poor sleep quality, symptoms of obstructive sleep apnea (OSA), and prolonging napping, after extensive adjustment.
Led by Christine E. McCarthy, MB, BCh, BAO, MSc, Department of Medicine, University of Galway, the case-control study included 4496 matched participants, of which 1799 experienced an ischemic stroke and 439 an intracerebral hemorrhage. Sleep symptoms in the previous month were assessed through a questionnaire that addressed areas of nocturnal sleep duration, sleep quality, sleep onset latency, nocturnal awakening, sleeping during the day, snoring, snorting or gasping, and breathing cessation or choking during sleep.
For symptoms of snoring, snorting, and breathing cessation during sleep, investigators derived an OSA score ranging from 0-3, with lower scores signifying a lower probability of sleep apnea. In the primary multivariable model, adjusted for age, occupation, marital status, and modified Rankin scale score, findings showed that short nocturnal sleep duration (<5 hours: OR, 3.15; 95% CI, 2.09-4.76) and long nocturnal sleep duration (>9 hours: OR, 2.67; 95% CI, 1.89-3.78) were associated with an increased odds of all stroke, compared with 7 hours, which served as the reference.
"Our findings also suggest a complex relationship of sleep impairment, intermediate cerebrovascular risk factors and stroke risk,” McCarthy et al concluded. “Given that individual sleep disturbance symptoms were common, and associated with increased odds of stroke, interventional studies in patients with high sleep disturbance burden, and in those with individual sleep symptoms, should be considered a priority research target, in the global effort to reduce stroke incidence."
A significant U-shaped association persisted in all multivariable models, with similar associations found in relation to both ischemic stroke (<5 hours: OR: 2.64, 95%CI: 1.69- 4.12; ><5 hours: OR, 2.64; 95% CI, 1.69-4.12; >9 hours: OR: 2.68, 95%CI: 1.81-3.98) and ICH (<5 hours OR: 9.12, 95%CI: 2.57-32.34; >9 hours: OR: 2.60, 95%CI: 1.23- 5.52). Self-reported or fair sleep quality (OR, 1.52; 95% CI, 1.32-1.75), sleep onset latency (OR, 1.32; 95% CI, 1.13-1.55) and frequent walking (OR, 1.33; 95% CI, 1.13-1.53) were associated with an increased odds of acute stroke in the primary model; however, only sleep quality remained significantly associated after further adjustment for potential mediators.
After adjusting for potential mediators, investigators found that that napping of long duration remained significantly associated with stroke. In a combined analysis, the highest OR for stroke and napping was with unplanned napping (OR, 2.46; 95% CI, 1.69-3.57) and the lowest OR associated was with short (≤1 hour) planned napping (OR, 0.91; 95% CI, 0.76-1.08).
Self-reported snoring (OR: 1.91, 95%CI: 1.62-2.24), snorting (OR: 2.64, 95%CI: 2.17-3.20), and breathing cessation (OR: 2.87, 95%CI: 2.28-2.60) were associated with statistically significant increased odds of all stroke in the primary model, maintaining significance with all further adjustment. Additionally, patients with an OSA score between 2-3 were associated with significantly greater odds of stroke (OR, 2.67; 95% CI, 2.25-3.15), ICH (OR, 4.07; 95% CI, 2.73-6.08) and ischemic stroke (OR, 2.39; 95% CI, 1.98-2.89) even after subsequent adjustment.
The number of sleep disturbance symptoms were linked with risk of stroke as well, as those with more than 5 symptoms had the highest OR, with 5.38 (95% CI, 4.03-7.18). Findings were also consistent for ischemic stroke (>5: OR, 5.06; 95% CI, 3.67-6.97) and ICH (>5: OR, 8.36; 95% CI, 4.05-17.26).
In terms of demographic variables, the study identified an interaction between sleep duration and both ethnicity (P <.001) and region (P <.001). In the primary model, the association between short sleep duration sleep and stroke was highest for South Asian ethnicity and South Asia, while non-significant for Chinese ethnicity and China.
