Samuelsson U, Johansson C, Carstensen J, Ludvigsson J
Department of Pediatrics, Regional Hospital Ryhov, Jönköping, Sweden.
Int J Epidemiol. 1994 Feb;23(1):138-42. doi: 10.1093/ije/23.1.138.
Using the method developed by Knox, space-time clustering was analysed in all 584 cases of insulin-dependent diabetes mellitus (IDDM) diagnosed between 1977-1990 and below the age of 16 from four paediatric departments in south-east Sweden. The catchment areas of these clinics form a contiguous geographical area of 26,445 km2 with a total of 165,784 children aged 0-15 years. The annual incidence for the study period was 25.2 per 100,000 children aged 0-15 years with a statistically significant incidence variation between the years; highest incidence in 1983 (39.2) and lowest in 1977 and 1989 (18.9 and 20.7 respectively). In the analysis, 30 different combinations of critical cutoff values were used to define closeness in space and time of pairs of cases. Statistically significant results were seen for several combinations with the highest significance obtained for the cutoff values of 15 km and 7 months, respectively. This space-time clustering tended to be specially pronounced during the period with the highest incidence of IDDM, 1981-1985. Our results indicate that space-time clustering exists in IDDM. These findings may support the hypothesis that infectious agents (possibly viral) give rise to a portion of IDDM.
采用诺克斯开发的方法，对瑞典东南部四个儿科部门在1977年至1990年期间诊断出的、年龄在16岁以下的所有584例胰岛素依赖型糖尿病（IDDM）病例进行了时空聚类分析。这些诊所的服务区域形成了一个面积为26445平方公里的连续地理区域，共有165784名0至15岁的儿童。研究期间的年发病率为每10万名0至15岁儿童中有25.2例，各年份之间的发病率存在统计学上的显著差异；1983年发病率最高（39.2），1977年和1989年发病率最低（分别为18.9和20.7）。在分析中，使用了30种不同的临界截断值组合来定义病例对在空间和时间上的接近程度。几种组合出现了统计学上的显著结果，其中分别以15公里和7个月的截断值获得的显著性最高。这种时空聚类在IDDM发病率最高的时期，即1981年至1985年期间，往往特别明显。我们的结果表明IDDM中存在时空聚类。这些发现可能支持感染因子（可能是病毒）导致部分IDDM的假说。
