Association of Sleep-disordered Breathing and the Occurrence of Stroke

TLDR

Sleep‑disordered breathing has been linked to stroke in prior studies. The study aims to determine whether sleep‑disordered breathing increases stroke risk. The authors conducted cross‑sectional and longitudinal analyses of 1,475 and 1,189 general‑population subjects, using attended polysomnography to define sleep‑disordered breathing by apnea–hypopnea index and repeating the protocol every four years. Cross‑sectional analysis showed that an apnea–hypopnea index ≥20 was associated with a 4.33‑fold higher odds of stroke, and prospective analysis indicated a 4.31‑fold increased risk of first‑ever stroke over four years, though the adjusted association was not statistically significant.

Abstract

Rationale: Sleep-disordered breathing has been linked to stroke in previous studies. However, these studies either used surrogate markers of sleep-disordered breathing or could not, due to cross-sectional design, address the temporal relationship between sleep-disordered breathing and stroke.Objectives: To determine whether sleep-disordered breathing increases the risk for stroke.Methods: We performed cross-sectional and longitudinal analyses on 1,475 and 1,189 subjects, respectively, from the general population. Sleep-disordered breathing was defined by the apnea–hypopnea index (frequency of apneas and hypopneas per hour of sleep) obtained by attended polysomnography. The protocol, including polysomnography, risk factors for stroke, and a history of physician-diagnosed stroke, was repeated at 4-yr intervals.Measurements and Main Results: In the cross-sectional analysis, subjects with an apnea–hypopnea index of 20 or greater had increased odds for stroke (odds ratio, 4.33; 95% confidence interval, 1.32–14.24; p = 0.02) compared with those without sleep-disordered breathing (apnea–hypopnea index, <5) after adjustment for known confounding factors. In the prospective analysis, sleep-disordered breathing with an apnea–hypopnea index of 20 or greater was associated with an increased risk of suffering a first-ever stroke over the next 4 yr (unadjusted odds ratio, 4.31; 95% confidence interval, 1.31–14.15; p = 0.02). However, after adjustment for age, sex, and body mass index, the odds ratio was still elevated, but was no longer significant (3.08; 95% confidence interval, 0.74–12.81; p = 0.12).Conclusions: These data demonstrate a strong association between moderate to severe sleep-disordered breathing and prevalent stroke, independent of confounding factors. They also provide the first prospective evidence that sleep-disordered breathing precedes stroke and may contribute to the development of stroke.