Sleep disturbances linked to increased risk of acute stroke

By Dr. Chinta SidharthanReviewed by Danielle Ellis, B.Sc.Apr 10 2023

In a recent study published in the journal Neurology, researchers investigated how a wide range of symptoms of sleep disturbance, individually and cumulatively, could be associated with the risk of acute stroke.

Study: Sleep Patterns and the Risk of Acute Stroke: Results from the INTERSTROKE International Case-Control Study. Image Credit: amenic181 / Shutterstock

Background

The prevalence of sleep impairments and deprivation is on the rise worldwide and is linked to a host of other health problems. Sleep impairments could range from poor sleep quality, deviations in sleep duration, difficulty initiating and maintaining sleep, and associated symptoms such as snorting, snoring, and cessation of breathing, to complex sleeping disorders.

Various studies have examined the link between parameters of sleep impairments and acute stroke. However, the evaluation of all the relevant domains of sleep and their independent roles in health has been either incomplete or infrequent. Furthermore, most of these studies have focused on single countries, and the representation of the study population has not been diverse. While strong evidence links obstructive sleep apnea and the risk of acute stroke, the association between stroke and other symptoms of sleep impairment remains unclear.

About the study

In the present study, the researchers examined the association between individual and cumulative symptoms of sleep impairment using an international case-control study called INTERSTROKE that examines stroke risk factors. The study enrolled patients who experienced acute stroke (based on the clinical definition by the World Health Organization (WHO)), with the current symptom onset being within three days. Cases involving aphasia or severe stroke were included based on the availability of a valid proxy respondent. The cases were classified based on the hour of onset and the occurrence of symptoms upon waking as intracranial hemorrhage or ischemic stroke.

Age, sex, and, in relevant cases, ethnicity-matched controls with no history of stroke were recruited for each case. A sleep questionnaire was used to collect information on sleep behaviors before the occurrence of the stroke, including aspects such as the duration of nocturnal sleep, the quality of sleep, latency in sleep onset, duration and intent of sleep during the day, waking up at night, cessation of breath during sleep, and snorting, gasping, snoring, or choking during sleep. In addition, clinical measurements were obtained from all participants, including non-fasting blood samples, weight, and blood pressure.

Information on covariates such as occupation, marital status, alcohol consumption, diet, body mass index, weight-to-hip ratio, depression, stress, hypertension, and diabetes was also collected.

Results

The results indicated that not only were symptoms of sleep disturbance common in this international cohort, but these symptoms were associated with a graded increase in the risk of stroke. The symptoms with significant associations with an increased risk of acute stroke included short sleep of fewer than five hours, long sleep extending beyond nine hours, impaired quality of sleep, difficulty in falling asleep or maintaining sleep, prolonged or unplanned napping, snorting, snoring, and cessation of breath during sleep. The sleep symptoms were also cumulatively associated with an increased risk of stroke in a graded manner.

Although the study found that daytime sleeping or napping was associated with an elevated risk of cardiovascular disease, there are conflicting findings that siestas are healthy. The authors believe that the association between napping and the risk of stroke is contextual in the international setting and that while planned short-duration naps such as siestas were not linked to an increased risk of stroke, long and unplanned naps, especially in individuals who sleep for more than six hours during the night, was associated with a higher risk of acute stroke.

The results also suggest that symptoms that represented obstructive sleep apnea could independently be associated with the risk of stroke. While snoring has commonly been studied in connection with sleep apnea, symptoms such as cessation of breath and snorting have not been studied at the same frequency, and the results indicate that these symptoms might independently be associated with the risk of stroke, irrespective of the severity or treatment of obstructive sleep apnea.

Conclusions

Overall, the findings suggested that a range of sleep impairment symptoms such as lack of adequate sleep, extended duration of sleep, unplanned and prolonged naps, snorting, snoring, or the cessation of breath during sleep, poor quality of sleep, as well as difficulty initiating or maintaining sleep were not only independently associated with a risk of acute stroke, but also increased the risk of stroke cumulatively in a graded manner. These symptoms can be used as independent markers to determine the increased individual risk of stroke.