Circadian variation in stroke - a prospective hospital-based study.

A particular pattern of circadian variation of cardiovascular and cerebrovascular diseases has been reported in the literature. The circadian periodicity of ischaemic stroke with peak onset in the morning hours may not be a random event and could depend on some underlying precipitating and associated cardiovascular risk factors. In a prospective observational study, we observed that ischaemic stroke onset was significantly higher in late morning hours between 6.00 and 12.00 hours. Ischaemic heart disease and hypertension were significantly associated with the occurrence of late morning ischaemic strokes. Further studies in the future are needed to understand the significance of this association and whether these risk factors are implicated in the pathogenesis of stroke.