Department of Behavioral and Social Sciences, Public Health Program, Brown University, Providence, RI 02912, USA.
Cancer Epidemiol Biomarkers Prev. 2012 Sep;21(9):1450-7. doi: 10.1158/1055-9965.EPI-11-1223. Epub 2012 Jun 26.
We used a composite variable composed of insurance status, income, and race/ethnicity to investigate access-enhancing programs as a possible reason for "reversals of association" and large percent changes (LPC), between race/ethnicity and cancer screening, when comparing the unadjusted and adjusted ORs.
Data were from women aged 40-64 years, using the combined 2008 and 2010 Behavioral Risk Factor Surveillance System surveys. Recent mammography was within the past 2 years, and recent Pap testing was within the past 3 years. Initial analyses using all variables singly were followed by analyses that used the composite variable with the remaining covariates.
Analyses with race/ethnicity singly indicated reversals of association for Hispanic women and higher estimated screening for black and Hispanic women than for white women. Analyses with the composite variable found no reversals of association, but there were several LPCs for Hispanic and black women, for lower income, and for uninsured women. White, uninsured, lower income women were among those with the lowest utilization.
Results were consistent with the possibility that access-enhancing programs for lower income, uninsured and often non-white women can lead to overestimates of screening, reversals of association, and LPCs in multivariable analyses. Attention should be given to identifying LPCs to unadjusted ORs. Lower income, uninsured, white women are also a group at risk of extremely low mammography and Pap test utilization.
Combining variables to create better-targeted population subgroups may help in the interpretation of analyses that produce reversals of association and LPCs for correlates of cancer screening utilization.
我们使用由保险状况、收入和种族/民族组成的复合变量来研究增强获取途径的项目，这些项目可能是导致种族/民族与癌症筛查之间“关联反转”和百分比变化（LPC）较大的原因，在比较未调整和调整后的 OR 时。
数据来自年龄在 40-64 岁的女性，使用 2008 年和 2010 年行为风险因素监测系统调查的合并数据。最近的乳房 X 光检查在过去 2 年内，最近的巴氏涂片检查在过去 3 年内。最初的分析使用了所有变量，然后使用剩余协变量的复合变量进行了分析。
使用种族/民族单独分析表明，西班牙裔女性的关联发生了反转，而且黑人和西班牙裔女性的估计筛查率高于白人女性。使用复合变量的分析没有发现关联反转，但对于西班牙裔和黑人群体，对于低收入和没有保险的女性，存在几个 LPC。没有保险、收入较低的白人女性是利用率最低的群体之一。
结果与以下可能性一致，即增强获取途径的项目对于低收入、没有保险且往往是非白人女性，可能导致对筛查的高估、多变量分析中的关联反转和 LPC。应该注意识别 LPC 对未调整的 OR。低收入、没有保险、白人女性也是乳腺癌和巴氏涂片检查利用率极低的群体之一。
将变量组合起来创建更有针对性的人群亚组，可能有助于解释产生癌症筛查利用率相关性关联反转和 LPC 的分析。
