Background Strong observational evidence exists, from small- and medium-scale studies, linking short, disturbed and poor quality sleep with metabolic and cardiovascular disorders. However, the extent to which such evidence might be generalisable to the general population remains unclear, and to-date there have been no large-scale nationally representative analyses of these associations.
Methods To establish the contemporary relevance of sleep as a correlate of stroke among adults in the UK, we examined the relationship between seven self-reported sleep measures (duration; latency; wakefulness; coughing/snoring; perceived quality; medication; and daytime sleepiness) and self-reported stroke in the first wave of a large (n = 50,994) nationally representative cohort study (Understanding Society). The association between self-reported sleep measures and self-reported stroke was examined before and after adjusting for: age; sex; body mass index; educational attainment; employment status; ethnicity; household income; and General Health Questionnaire (GHQ) caseness – all of which had been identified as potential confounders using a directed acyclic graph.
Results There were strong, graded and statistically significant associations between all seven self-reported sleep measures and stroke before adjustment for potential confounders. All of these associations were attenuated following adjustment, yet all but one (sleep duration) remained statistically significant. For these six self-reported sleep variables, respondents reporting ‘very bad’ sleep quality had more than three times the odds of stroke than those reporting ‘very good’ sleep quality (OR: 3.31; 95% CI:2.25, 4.86); whilst those who reported that on ‘most nights’ they: could not ‘get to sleep within 30 min’; ‘wake in the middle of the night’; and ‘cough or snore loudly’ had 2.68 (95% CI: 2.01, 3.58), 1.17 (95% CI: 0.85, 1.62) and 1.70 (95% CI: 1.26, 2.28) the odds of stroke, respectively, than those who reported that these had ‘not [occurred] in the past month’. Likewise, respondents reporting frequent (‘≥3x a month’) use of ‘medication to sleep’ and ‘trouble staying awake’ had 1.70 (95% CI: 1.05, 1.07) and 2.12 (95% CI: 1.21, 3.71) the odds of stroke, respectively, compared to those not using medication or struggling to stay awake ‘in the past month’
Conclusion These findings confirm that a wide range of sleep-related characteristics are associated with stroke and, in particular, that perceived sleep quality (a likely indicator of satisfaction with sleep) and trouble sleeping due to breathing problems (a likely indicator of sleep apnoea) had the strongest associations with stroke. It remains to be seen whether these cross-sectional associations reflect a causal relationship between sleep and stroke and, if so, the relative importance of sleep as a determinant of stroke and vice versa.
- understanding society