空间流行病学分析中细小单元的区域化归并方法:以义乌市甲状腺癌为例

目的 空间流行病学研究中,细小地域单元由于人口数目少,偶发的个别病例出现就有可能导致极值的产生,给真实发病的分析带来困难。本研究以浙江省义乌市甲状腺癌2010-2013年监测数据和人口资料为基础,利用不同的区域划分描述甲状腺癌空间分布规律,探测病例空间聚集热点,为进一步开展环境和人群监测提供参考依据,同时评价小单元区域化在空间流行病学研究中的应用价值。方法 采用基于地理环境相似性(同质性检验)和空间相邻原则集群和分区的区域化方法,利用地理信息系统(GIS)将人口较少村落合并为具有足够人口基数的地理单元,以增加率值估计的稳定性和可靠性。结果 研究区新产生的区域单元具有足够的人口基数,产生的甲状腺癌发病率稳定和正态化。对新的区域单元进行热点探测(Getis-Ord)发现研究区中部平原地区有显著的高发病聚集。结论 小单元区域化方法能有效解决人口基数过小问题,有助于空间热点的探测与分析,能为进一步探寻甲状腺癌的危险因素提供依据。

Hierarchical regionalization for spatial epidemiology:a case study of thyroid cancer incidence in Yiwu,Zhejiang

Objective Sporadic cases occurring in mall geographic unit could lead to extreme value of incidence due to the small population bases,which would influence the analysis of actual incidence. Methods This study introduced a method of hierarchy clustering and partitioning regionalization,which integrates areas with small population into larger areas with enough population by using Geographic Information System (GIS) based on the principles of spatial continuity and geographical similarity (homogeneity test). This method was applied in spatial epidemiology by using a data set of thyroid cancer incidence in Yiwu,Zhejiang province,between 2010 and 2013. Results Thyroid cancer incidence data were more reliable and stable in the new regionalized areas. Hotspot analysis (Getis-Ord) on the incidence in new areas indicated that there was obvious case clustering in the central area of Yiwu. Conclusion This method can effectively solve the problem of small population base in small geographic units in spatial epidemiological analysis of thyroid cancer incidence and can be used for other diseases and in other areas.