Prince M I, Chetwynd A, Diggle P, Jarner M, Metcalf J V, James O F
Centre for Liver Research, Newcastle Medical School, Framlington Place, Newcastle, England, UK.
Hepatology. 2001 Dec;34(6):1083-8. doi: 10.1053/jhep.2001.29760.
The incidence of primary biliary cirrhosis (PBC) varies widely between regions. However, little is known about variation within regions and the degree to which this may reflect environmental risk factors. The aim of this study was to describe the spatial distribution of cases of PBC in a defined region of Northeast England over a defined period, and to assess the magnitude of any departure from random spatial distribution. Seven hundred seventy patients with established PBC were identified in a previous comprehensive case finding study. A total of 3,044 control locations were randomly selected from postcode (zip code) data weighted for number of drop off points per postcode. Geographical analysis was performed by testing both for spatial variation in risk and local clustering by using previously described point process methods. Both tests used the same null hypothesis that risk of disease does not vary spatially and cases occur independently of each other. Statistically significant spatial variations in risk were found in the whole study region (P <.001) and in the major urban area within the region (P <.004). Risk was higher in the urban area of Tyneside than in the surrounding rural area. Within the rural area, spatial variation in risk was equivocal (P =.012), but there was significant (P =.001) clustering of cases (estimated average cluster effect approximately 10 excess cases within a 7-km radius). PBC occurred to a density of 10.7 cases/km(2) in the highest risk areas. In conclusion, PBC is unevenly distributed in Northeast England. This may reflect one or more environmental risk factors in its etiology.
原发性胆汁性肝硬化（PBC）的发病率在不同地区差异很大。然而，关于地区内部的差异以及这种差异在多大程度上可能反映环境风险因素，人们了解甚少。本研究的目的是描述在英格兰东北部一个特定区域内特定时间段PBC病例的空间分布，并评估与随机空间分布的偏离程度。在之前一项全面的病例发现研究中确定了770例确诊的PBC患者。从邮政编码数据中随机选择了3044个对照地点，并根据每个邮政编码的投递点数量进行加权。通过使用先前描述的点过程方法，对风险的空间变异和局部聚集性进行检验，从而进行地理分析。这两种检验都使用相同的零假设，即疾病风险在空间上没有变化，病例彼此独立发生。在整个研究区域（P <.001）和该区域内的主要城市地区（P <.004）均发现了具有统计学意义的风险空间变异。泰恩赛德市区的风险高于周边农村地区。在农村地区，风险的空间变异不明确（P =.012），但病例存在显著的聚集性（P =.001）（估计平均聚集效应为在7公里半径内约有10例额外病例）。在风险最高的地区，PBC的发病密度为每平方公里10.7例。总之，PBC在英格兰东北部分布不均。这可能反映了其病因中的一种或多种环境风险因素。
