Roush G C, Schymura M J, Holford T R
Department of Epidemiology and Public Health, Yale University, New Haven, Connecticut 06510.
Cancer. 1988 Jun 15;61(12):2586-95. doi: 10.1002/1097-0142(19880615)61:12<2586::aid-cncr2820611233>3.0.co;2-2.
The decades-long increase in incidence rates for melanoma has been ascribed to artifactual changes in case ascertainment rather than to true changes in disease risk. In this study, population-based incidence data for invasive cutaneous malignant melanoma from the Connecticut Tumor Registry were categorized into seven age groups and four time periods to examine the pattern of change over four decades. Analyses of age, period, and cohort variables focused on the curvature components, which are estimable functions. Statistical modeling demonstrated the following: (1) incidence rates have increased by birth cohort in both sexes with no requirement for a period variable, regardless of whether data are examined by 10-year, 5-year, or 1-year intervals of diagnosis; (2) this pattern in incidence rates differed from the patterns of change in the two indices of case ascertainment, the proportion of cases confirmed microscopically and the proportion of cases in localized stage, both of which exhibited changes by period of diagnosis rather than by birth cohort; and (3) adjustment for these two indices caused a downward bend in the cohort curve for females but not for males. The results suggested that much of the observed increase for this tumor was real.
黑色素瘤发病率数十年来的上升一直被归因于病例确诊方面的人为变化，而非疾病风险的真实变化。在本研究中，将来自康涅狄格肿瘤登记处的侵袭性皮肤恶性黑色素瘤的基于人群的发病率数据分为七个年龄组和四个时间段，以研究四十年来的变化模式。对年龄、时期和队列变量的分析集中在曲率成分上，曲率成分是可估计函数。统计建模表明：（1）无论数据按诊断的10年、5年或1年间隔进行检查，发病率在两个性别中均随出生队列增加，且不需要时期变量；（2）发病率的这种模式与病例确诊的两个指标的变化模式不同，这两个指标分别是显微镜确诊病例的比例和局部阶段病例的比例，二者均表现出随诊断时期而非出生队列的变化；（3）对这两个指标进行调整导致女性队列曲线向下弯曲，但男性没有。结果表明，该肿瘤观察到的大部分增加是真实的。
