Oberg A L, Ferguson J A, McIntyre L M, Horner R D
Department of Statistics, North Carolina State University, Raleigh, USA.
Am J Epidemiol. 2000 Sep 15;152(6):558-64. doi: 10.1093/aje/152.6.558.
Evidence of seasonal variation in the incidence of stroke is inconsistent. This may be a likely consequence of one or more methodological shortcomings of the studies investigating this issue, including inappropriate analytic models, insufficient length of time, small sample size, and a regional (vs. national) focus. The authors' objective was to ascertain whether an association exists between season of the year and the incidence of stroke by using a methodological approach designed to overcome these limitations. The authors used a longitudinal study design involving 72,779 veterans hospitalized for stroke at any Veterans Affairs hospital nationally during the years 1986-1995. These data were analyzed by using time series methods. There was clear evidence of a seasonal occurrence for stroke in general. This seasonal effect was found for ischemic stroke, but not for hemorrhagic stroke. The peak occurrence was in mid-May. Neither the region (i.e., climate) nor the race of the patient substantially modified the seasonal trend. An explanation for this pattern remains to be determined.
中风发病率季节性变化的证据并不一致。这可能是研究此问题的一项或多项方法学缺陷导致的结果，这些缺陷包括分析模型不当、时间跨度不足、样本量小以及关注区域（而非全国）。作者的目的是通过采用旨在克服这些局限性的方法来确定一年中的季节与中风发病率之间是否存在关联。作者采用了纵向研究设计，纳入了1986年至1995年期间在全国任何一家退伍军人事务医院因中风住院的72779名退伍军人。这些数据采用时间序列方法进行分析。总体而言，有明确证据表明中风存在季节性发作。这种季节性效应在缺血性中风中存在，但在出血性中风中不存在。发病高峰在5月中旬。患者的地区（即气候）和种族均未对季节性趋势产生实质性影响。这种模式的解释仍有待确定。
