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Sleep and brain health

Stroke is the second cause of death and one of the leading causes of disability.1 Worldwide, fifteen million people suffer a stroke every year, nearly six million die, and around five million are left permanently disabled.2,3 The identification of the risk factors of stroke, especially those that can be modified, is of paramount relevance to control the burden of cerebrovascular diseases.4,5 In the current issue of The Journal of Clinical Hypertension, the study by Dr Hua and colleagues aimed to examine the association between sleep duration and stroke risk in middle-aged and elderly population.6 The cross-sectional study included 10 516 participants aged ≥45 years from the China Hypertension Survey study, a nationally representative cross-sectional survey designed to provide reliable and evidence-based data on the current status of hypertension and associated factors in Chinese adults. Longer sleep duration was associated with higher prevalence of stroke: the relationship resulted linear in non-hypertensive patients with a turning point of the smooth curve at 8 hours, whereas a threshold effect was found in hypertensive individuals.6 Despite methodological issues inherent to the cross-sectional and self-reported nature of data, which may be subjected to recall biases and possible residual or unmeasured confounders, the study can offer intriguing insights for the understanding of behavioral contributors to stroke.