Sleep Disturbances Associated With Increased Stroke Risk

Sleep disturbance symptoms are associated with a graded increased risk of stroke, and the symptoms might be an indicator of increased individual risk or represent independent risk factors, according to a study published in Neurology, the medical journal of the American Academy of Neurology.¹ Future clinical trials are needed to determine how effective sleep interventions will be in stroke prevention.

This study was conducted because sleep disturbance symptoms are common and may indicate important, treatable risk factors for stroke. Getting enough sleep is necessary for health, and sleep impairments represent a range of disturbance. Researchers analyzed the association between a range of sleep disturbance symptoms and acute stroke risk in an international setting.

First, a large, international case-control study of patients presenting with first stroke and matched controls, called INTERSTROKE, was used. Controls were matched by age (±5 years) and sex. Average participant age was 62, according to a press release.²

Then, sleep symptoms in the past month were evaluated via a questionnaire, and conditional logistic regression estimated the associations between sleep disturbance symptoms and acute stroke, which were shown as odds ratios (ORs) and 95% CIs.

In total, there were 4496 matched participants, including 1799 participants who had an ischemic stroke and 439 who had an intracerebral hemorrhage. Short sleep (<5 hours: OR, 3.15; 95% CI, 2.09-4.76), long sleep (> 9 hours: OR, 2.67; 95% CI, 1.89-3.78), impaired quality (OR, 1.52; 95% CI, 1.32-1.75), trouble getting to sleep (OR, 1.32; 95% CI, 1.13-1.55) or maintaining sleep (OR, 1.33; 95% CI, 1.15-1.53), unplanned napping (OR, 1.59; 95% CI, 1.31-1.92), prolonged napping (>1 hour: OR, 1.88; 95% CI, 1.49-2.38), 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 all significantly associated with increased likelihood of acute stroke in the primary model.

A derived obstructive sleep apnea (OSA) score of 2 to 3 (OR, 2.67; 95% CI, 2.25-3.15) and cumulative sleep symptoms (>5: OR, 5.06; 95% CI, 3.67-6.97) were also associated with a significantly increased likelihood of acute stroke, with the latter displaying a graded association. After extensive adjustment, significance was maintained for most symptoms (not difficulty getting to/maintaining sleep and unplanned napping), with similar findings for stroke subtypes.

Study author Christine Mc Carthy, MB, BCh, BAO, of University of Galway in Ireland, said in the press release, “Our results suggest that sleep problems should be an area of focus for stroke prevention.”

Additionally, this study suggests that confounders and mediators of short vs long sleep duration differ, and that long sleep duration is more likely to have an independent association with acute stroke.

Researchers also found that symptoms were common before stroke in this study, as 59% of cases reported snoring, 25% reported snorting, and 19% reported breathing cessation. Unawareness of OSA symptoms rather than absence has important implications for questionnaire-based OSA screening and clinical research.

To the researchers’ knowledge, this study is the most extensive on sleep disturbances in this context. They emphasize that even if the relationship is not causal, individuals with multiple sleep disturbance symptoms should be thought of as being at high risk of stroke.

Subjective reporting was used to determine sleep symptoms, which could be a limitation. Also, incident stroke might result in sleep disturbance, so there is a risk of misclassification and recall bias. Additionally, the researchers were unable to adjust for shift work or sedative use, and diagnosed OSA levels were low.

“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,” the researchers concluded.

References

1. Mc Carthy CE, Yusuf S, Judge C, et al. Sleep patterns and the risk of acute stroke: results from the INTERSTROKE international case-control study. Neurology. Published online April 5, 2023. doi:10.1212/WNL.0000000000207249

2. Sleep problems? you may have an increased risk of stroke. News release. American Academy of Neurology. March 31, 2023. Accessed April 5, 2023. https://www.newswise.com/articles/sleep-problems-you-may-have-an-increased-risk-of-stroke