Number of Sleep Disturbance Symptoms May Impact Stroke Risk

Sleep disturbance is common worldwide and associated with an increased risk for stroke, according to the results of an international case-control study published in Neurology.

There has been some evidence that stroke risk may be associated with sleep characteristics; however, data are not robust.

The INTERSTROKE study was a large international case-control study where researchers recruited patients with stroke and matched them with nonstroke control individuals. In this analysis, data from a supplementary questionnaire about sleep, which was introduced in 2012, were evaluated for trends in sleep disturbance in the setting of stroke.

This study comprised 2,243 stroke cases and 2,253 control individuals. The patients with stroke and control individuals were:

• mean age, 63 (Standard deviation [SD], 14) and 62 (SD, 14) years (P <.001),
• 58% and 58% were men,
• they had a body mass index (BMI) of 26.4 (SD, 5.0) and 25.8 (SD, 4.8) kg/m² (P <.001),
• 78% and 70% had a modified Rankin Scale (mRS) score of 0 (P <.001), and
• 83% and 73% were mainly inactive (P <.001), respectively.

Study cohorts were recruited in Western Europe/North America/Australasia (25%), South Asia (23%), China (18%), Eastern/Central Europe/Middle East (16%), Africa (7.9%-8.1%), South America (5.8%), and South East Asia (3.6%).

Overall, patients with stroke self-rated their overall sleep quality as poorer than the control individuals and more reported waking more than once, difficulty falling asleep, snoring, snorting, breathing cessation, and napping with longer-duration naps (all P <.001).

In the fully adjusted models, compared with sleeping for 7 hours per night, sleeping less than 5 (adjusted odds ratio [aOR], 1.99; 95% CI, 1.17-3.38), 5 (aOR, 2.06; 95% CI, 1.42-2.99), 9 (aOR, 1.41; 95% CI, 1.01-1.98), or more than 9 (aOR, 2.14; 95% CI, 1.46-3.15) hours a night increased risk for all stroke.

Stroke risk was also associated with breathing problems during sleep, specifically snoring (aOR, 1.75; 95% CI, 1.44-2.12), snorting or gasping (aOR, 2.41; 95% CI, 1.91-3.05), and breathing cessation or choking (aOR, 2.52; 95% CI, 1.92-3.31) compared with no such breathing difficulty during sleep.

In univariate analyses, stroke was associated with:

• fair or bad sleep compared with good sleep (odds ratio [OR], 1.73),
• sleep onset latency compared with no latency (OR, 1.55),
• waking more than once compared with once or fewer (OR, 1.61), and
• long unplanned napping (OR, 2.88), long planned napping (OR, 1.78), and short unplanned napping (OR, 2.05), compared with no napping.

However, in all stroke cases except for long unplanned napping (absolute risk reduction [aRR], 1.65), risks were attenuated in the fully adjusted models.

Overall, risk for stroke increased with the burden, or number, of sleep problems from an OR of 1.63 for 2-3 problems to an OR of 5.38 for more than 5.

Significant interactions were observed between sleep duration and snoring (P =.002), ethnicity (P <.001), and region (P <.001).

The major limitation of the study was that data were based on subjective reporting.

The researchers concluded, “[O]ur results suggest that individual and cumulative symptoms of sleep disturbance may be important modifiable risk factors for stroke, and/or their presence identifies individuals at increased risk of stroke.”

Disclosures: This research was supported by Astra Zeneca, Boehringer Ingelheim, Pfizer, MERCK, Sharp and Dohme. Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.