Foerch Christian, Korf Horst-Werner, Steinmetz Helmuth, Sitzer Matthias
Department of Neurology, Goethe University, Schleusenweg 2-16, 60528 Frankfurt am Main, Germany.
Circulation. 2008 Jul 15;118(3):284-90. doi: 10.1161/CIRCULATIONAHA.108.771246. Epub 2008 Jun 23.
Stroke onset shows a pattern of diurnal variation, with a peak in morning hours. Rhythmic changes in blood pressure, hormones, and other parameters have been suggested as underlying mechanisms, but exogenous factors such as increasing physical activity after awakening may also be of relevance. To characterize the impact of external clock changes on the rhythmic variation in stroke onset, this parameter was recorded in patients during transition periods into and out of Daylight Saving Time (DST).
The present study was based on a prospective stroke registry in Germany that contains time points of stroke onset from 44 251 patients admitted between 2000 and 2005. To achieve a uniform timeline, time points of stroke onset were set back from Central European Summer Time (CEST) to Central European Time (CET) for patients admitted during DST periods. Compared with the last week before the clock change, transition to or from DST resulted in an immediate shift of stroke onset time points within the first week after the clock change in reference to the uniform timeline (transition from CET to CEST -60 minutes for the time points in both the 25th and 50th percentiles of the diurnal pattern, P<0.001; transition from CEST to CET +60 minutes for the time points in both the 25th and 50th percentiles, P<0.001; patients pooled on a weekly basis). A significant shift was already present the first and second day after the transitions (ie, Monday and Tuesday).
Transition to or from DST is coupled with an immediate shift in the time pattern of stroke onset. This strengthens the idea that exogenous factors associated with awakening are important determinants of the pattern of diurnal variation of stroke onset, because entrainment of the human circadian clock within hours is unlikely.
中风发作呈现出昼夜变化模式，在早晨时段达到高峰。血压、激素及其他参数的节律性变化被认为是潜在机制，但诸如醒来后身体活动增加等外在因素可能也有关联。为了描述外部时钟变化对中风发作节律性变化的影响，在采用和取消夏令时（DST）的过渡期内对患者的这一参数进行了记录。
本研究基于德国一项前瞻性中风登记处的数据，其中包含2000年至2005年间收治的44251例患者的中风发作时间点。为了实现统一的时间线，将夏令时期间收治患者的中风发作时间点从欧洲中部夏令时（CEST）调整为欧洲中部时间（CET）。与时钟变化前的最后一周相比，采用或取消夏令时导致中风发作时间点在时钟变化后的第一周内相对于统一时间线立即发生偏移（从CET转换为CEST时，昼夜模式第25和第50百分位数的时间点均提前60分钟，P<0.001；从CEST转换为CET时，第25和第50百分位数的时间点均推迟60分钟，P<0.001；按周汇总患者）。在转换后的第一天和第二天（即周一和周二）就已经出现了显著偏移。
采用或取消夏令时与中风发作时间模式的立即偏移相关。这强化了这样一种观点，即与醒来相关的外在因素是中风发作昼夜变化模式的重要决定因素，因为在数小时内使人的昼夜节律时钟同步是不太可能的。
