Samuelsson U, Löfman O
Division of Paediatrics, Department of Molecular and Clinical Medicine, University Hospital, S-581 85 Linköping, Sweden.
J Epidemiol Community Health. 2004 May;58(5):388-92. doi: 10.1136/jech.2002.004135.
As earlier studies have shown space-time clusters at onset of type 1 diabetes in the south east region of Sweden we investigated if there also has been any geographical clusters of diabetes in this region.
The place of residence (coordinates) at the time of diagnosis were geocoded in a geographical information system (GIS). All children diagnosed with type 1 diabetes up to 16 years of age at diagnosis between 1977-1995 were included. The population at risk was obtained directly from the population registry for the respective years and geographical area levels.
South east region of Sweden containing 5 counties, 49 municipalities, and 525 parishes.
A significant geographical variation in incidence rate were found between the municipalities (p<0.001) but not between the counties. The variation became somewhat weaker when excluding the six largest municipalities (p<0.02). In municipalities with increased risk (>35.1/100 000) the major contribution comes from children in age group 6-10 years of age at diagnosis. There were no obvious differences between the age groups in municipalities with decreased risk (<20.1/100 000). Boys and girls had about the same degree of geographical variation.
Apart from chance, the most probable explanation for the geographical variation in the risk for children and adolescents to develop type 1 diabetes between the municipalities in the region is that local environmental factors play a part in the process leading to the disease.
由于早期研究已表明瑞典东南部1型糖尿病发病存在时空聚集现象，我们调查了该地区是否也存在糖尿病的地理聚集情况。
诊断时的居住地（坐标）在地理信息系统（GIS）中进行地理编码。纳入了1977年至1995年期间诊断时年龄在16岁及以下的所有1型糖尿病患儿。风险人群直接从各年份和地理区域层面的人口登记处获取。
瑞典东南部地区，包括5个县、49个市和525个教区。
各市镇之间的发病率存在显著地理差异（p<0.001），但各县之间没有差异。排除六个最大的市镇后，这种差异有所减弱（p<0.02）。在风险增加的市镇（>35.1/10万）中，主要贡献来自诊断时年龄在6至10岁的儿童。在风险降低的市镇（<20.1/10万）中，各年龄组之间没有明显差异。男孩和女孩的地理差异程度大致相同。
除了偶然性因素外，该地区各市镇儿童和青少年患1型糖尿病风险存在地理差异的最可能解释是，当地环境因素在导致该疾病的过程中起到了一定作用。
