Andersson R, Hugander A, Thulin A, Nyström P O, Olaison G
Department of Surgery, Ryhov Hospital, Jönköping, Sweden.
Int J Epidemiol. 1995 Aug;24(4):829-33. doi: 10.1093/ije/24.4.829.
The aetiology of appendicitis, the commonest cause of acute abdomen, is unknown. Infection has been proposed but the evidence has been unconvincing. The purpose of the present study was to investigate if temporo-spatial clustering and outbreaks, characteristics of infectious diseases, could be found in appendicitis cases in a defined Swedish population.
Temporo-spatial clustering among 1155 cases from three districts of Jönköping County in 1984-1990 was identified by Knox space-time cluster analysis. Outbreaks were identified by retrospective study of temporal variations in 3590 consecutive cases of acute appendicitis from the city of Jönköping in 1969-1990.
Space-time clustering was found among patients with operations less than 60 days apart (observed/expected [O/E]-ratio 1.46, P = 0.016). Subset analysis revealed clustering to be commonest among patients from the same households (O/E-ratio 6.52, P = 0.012), among patients younger than 15 years (O/E-ratio 3.61, P = 0.004) and among females (O/E-ratio 2.28, P = 0.004). Three outbreaks with a significantly increased number of cases were observed during the 22-year study period (O/E-ratio 1.6-2.2, P = 0.001-0.049).
The finding of temporo-spatial interaction and outbreaks among appendicitis cases supports the concept that appendicitis may be caused by infectious agents.
阑尾炎是急腹症最常见的病因，其病因尚不清楚。虽然有人提出感染是病因，但证据并不令人信服。本研究的目的是调查在瑞典特定人群的阑尾炎病例中，是否能发现时空聚集性和暴发这两种传染病的特征。
通过诺克斯时空聚类分析，确定了1984 - 1990年延雪平郡三个区1155例病例中的时空聚集性。通过对1969 - 1990年延雪平市3590例连续性急性阑尾炎病例的时间变化进行回顾性研究，确定了暴发情况。
发现手术间隔时间少于60天的患者之间存在时空聚集性（观察值/预期值[O/E]比为1.46，P = 0.016）。亚组分析显示，聚集性在来自同一家庭的患者中最为常见（O/E比为6.52，P = 0.012），在15岁以下的患者中（O/E比为3.61，P = 0.004）以及女性患者中（O/E比为2.28，P = 0.004）也较为常见。在22年的研究期间观察到三次病例数显著增加的暴发（O/E比为1.6 - 2.2，P = 0.001 - 0.049）。
阑尾炎病例中存在时空相互作用和暴发的发现支持了阑尾炎可能由传染因子引起的观点。
