Kulldorff M, Feuer E J, Miller B A, Freedman L S
Division of Cancer Prevention and Control, National Cancer Institute, Bethesda, MD 20892-7368, USA.
Am J Epidemiol. 1997 Jul 15;146(2):161-70. doi: 10.1093/oxfordjournals.aje.a009247.
High breast cancer mortality rates have been reported in the northeastern part of the United States, with recent attention focused on Long Island, New York. In this study, the authors investigate whether the high breast cancer mortality is evenly spread over the Northeast, in the sense that any observed clusters of deaths can be explained by chance alone, or whether there are clusters of statistical significance. Demographic data and age-specific breast cancer mortality rates for women were obtained for all 244 counties in 11 northeastern states and for the District of Columbia for 1988-1992. A recently developed spatial scan statistic is used, which searches for clusters of cases without specifying their size or location ahead of time, and which tests for their statistical significance while adjusting for the multiple testing inherent in such a procedure. The basic analysis is adjusted for age, with further analyses examining how the results are affected by incorporating race, urbanicity, and parity as confounding variables. There is a statistically significant and geographically broad cluster of breast cancer deaths in the New York City-Philadelphia, Pennsylvania, metropolitan area (p = 0.0001), which has a 7.4% higher mortality rate than the rest of the Northeast. The cluster remains significant when race, urbanicity, and/or parity are included as confounding variables. Four smaller subclusters within this area are also significant on their own strength: Philadelphia with suburbs (p = 0.0001), Long Island (p = 0.0001), central New Jersey (p = 0.0001), and northeastern New Jersey (p = 0.0001). The elevated breast cancer mortality on Long Island might be viewed less as a unique local phenomenon and more as part of a more general situation involving large parts of the New York City-Philadelphia metropolitan area. The several known and hypothesized risk factors for which we could not adjust and that may explain the detected cluster are most notably age at first birth, age at menarche, age at menopause, breastfeeding, genetic mutations, and environmental factors.
据报道，美国东北部乳腺癌死亡率较高，近期的关注焦点集中在纽约长岛。在本研究中，作者调查了高乳腺癌死亡率在东北部地区是否均匀分布，即任何观察到的死亡聚集现象是否仅可由偶然因素解释，还是存在具有统计学意义的聚集现象。获取了11个东北部州的所有244个县以及哥伦比亚特区1988 - 1992年女性的人口统计数据和特定年龄的乳腺癌死亡率。使用了一种最近开发的空间扫描统计方法，该方法在不预先指定病例聚集的大小或位置的情况下搜索病例聚集，并在针对此类程序中固有的多重检验进行调整的同时检验其统计学意义。基本分析针对年龄进行了调整，进一步的分析考察了将种族、城市化程度和生育状况作为混杂变量纳入后结果如何受到影响。在纽约市 - 宾夕法尼亚州费城大都市区存在一个具有统计学意义且地理范围广泛的乳腺癌死亡聚集区（p = 0.0001），其死亡率比东北部其他地区高7.4%。当将种族、城市化程度和/或生育状况作为混杂变量纳入时，该聚集区仍然具有统计学意义。该区域内的四个较小的子聚集区自身也具有显著意义：费城及其郊区（p = 0.0001）、长岛（p = 0.0001）、新泽西州中部（p = 0.0001）和新泽西州东北部（p = 0.0001）。长岛乳腺癌死亡率升高或许不应被视为一种独特的局部现象，而更应被视为纽约市 - 费城大都市区大部分地区更普遍情况的一部分。我们无法针对其进行调整且可能解释所检测到的聚集现象的几个已知和假设的风险因素最显著的是初产年龄、月经初潮年龄、绝经年龄、母乳喂养、基因突变和环境因素。
