An Investigation Of The Temporal Distribution Of Stroke Onset In Taiyuan And The Associated Factors

Objective:To investigate diurnal, weekly, and seasonal variations of intracerebral hemorrhage(ICH) and ischemic stroke(IS) onset in Taiyuan, in relation to traditional stroke risk factors. With a view to guide the allocation of medical resource for acute stroke management and to develop reasonable stroke prevention strategies.Methods:Consecutive stroke patients admitted to the Department of Neurology, The First Hospital of Shanxi Medical University and Shanxi Provincial People’s Hospital between January 1st 2013 and December 31 st 2014 were retrospectively studied. Patients’ information included the status of traditional risk factors and the time of stroke onset.Chi-square test for goodness of fit was used to determine whether the number of events differed diurnally, weekly, or seasonally. If any differences were significant in certain time periods, multi-nominal logistic regression was applied to investigate the variation of stroke onset and the association with traditional risk factors. P<0.05 was considered statistically significant.Results:1. 403 ICH patients were included in the present study. The occurrence of ICH was lower in summer(91 cases) compared with other seasons, but the seasonal distribution was not significant(P=0.604). The number of events was fewer on Monday(45 cases)compared with other weekdays, and the weekly distribution was not significant (P=0.170). However, there was significant diurnal variation in ICH onset(P<0.001).Compared with night, the risk of ICH in morning, afternoon and evening was 3.63(95%CI: 2.45-5.36), 2.56(95% CI: 1.70-3.86) and 2.97(95% CI: 1.99-4.43), respectively.After stratified by gender, age and different risk factors and adjusted for multi-risk factors, the ICH onset peak was still morning and evening, which was independent of traditional risk factors.2. 2132 IS events were involved in the present analysis. The number of IS events was smaller(497 events) in summer compared with other seasons(P=0.056). The onset of IS was lower in Tuesday(274 cases) compared with other seasons(P=0.416). While the diurnal variation of IS was statistically significant(P<0.001). The odds ratio of IS occurring in morning, afternoon and evening was 3.73(95% CI: 3.09-4.49), 2.96(95%CI: 2.44-3.58) and 1.89(95% CI: 1.54-2.32), respectively(with night as a reference).When stratified by gender, age and different risk factors and adjusted for multi-risk factors, we found a two-peak distribution with the first in morning and the second peak in afternoon, and the distribution was regardless of traditional risk factors status.Conclusion:1. The present study showed that the seasonal and weekly variation in ICH onset was not statistically significant. However, there was significant diurnal variation for ICH onset: with night as nadir, and morning and evening were two-peak. Besides, this pattern was independent of gender, age and traditional risk factors. The specific mechanism needs to be further investigated.2. Our study showed that seasonal and weekly variation for IS onset was not statistically significant. While the diurnal variation of IS was significant: compared with night, the incidence of IS in morning and afternoon was the dual-peak. And the distribution was regardless of traditional risk factors status. The underlined mechanism deserves further investigation.