Department of Epidemiology, University of Michigan,109 Observatory St., Ann Arbor, MI 48109, USA.
Cancer Epidemiol Biomarkers Prev. 2012 Jan;21(1):155-65. doi: 10.1158/1055-9965.EPI-11-0833. Epub 2011 Oct 25.
Inflammatory breast cancer (IBC) is a rare and highly aggressive form of primary breast cancer. Little is known about the risk factors for IBC, specifically the association with socioeconomic position (SEP).
The association between breast cancer type (IBC vs. non-IBC) with county-level SEP in the Surveillance, Epidemiology, and End Results database for cases diagnosed from 2000 to 2007 was examined. County-level SEP characteristics included metropolitan versus non-metropolitan residence, percentage below the poverty level, percentage less than high-school graduate, and an index combining the poverty and high-school variables. IBC and non-IBC age-adjusted incidence rates were calculated, stratified on SEP and race/ethnicity. The odds of IBC versus non-IBC given a particular SEP characteristic, adjusting for age and race/ethnicity, was examined through fitting of hierarchical logistic regression models (HLM).
Incidence rates for IBC generally increased as SEP decreased, whereas the opposite was found for non-IBC. HLM results showed that low SEP is associated with higher odds of IBC: highest (≥ 20%) versus lowest (<10%) persons below the poverty level [OR (95% confidence interval, CI) = 1.25 (1.09-1.43)]; highest (>28.76%) versus lowest (≤ 15.99%) persons less than high-school graduate [OR (95% CI) = 1.25 (1.10-1.42)]; and low SEP as measured by poverty-high school index versus high SEP [OR (95% CI)= 1.26 (1.11-1.44)].
Overall breast cancer has been found to be positively associated with SEP, whereas in this analysis, IBC was associated with decreasing SEP.
Studies focused on understanding the disparity in IBC incidence, as well as interventions to eliminate these differences are needed.
炎性乳腺癌（IBC）是一种罕见且高度侵袭性的原发性乳腺癌。目前对于 IBC 的风险因素知之甚少，特别是与社会经济地位（SEP）的关系。
本研究利用监测、流行病学和最终结果（SEER）数据库，分析了 2000 年至 2007 年诊断的病例中，乳腺癌类型（IBC 与非 IBC）与县一级 SEP 之间的关系。县一级 SEP 特征包括城市与非城市居住、贫困线以下百分比、未完成高中学业百分比以及综合贫困和高中学业变量的指数。计算了 IBC 和非 IBC 的年龄调整发病率，按 SEP 和种族/民族分层。通过拟合层次逻辑回归模型（HLM），在调整年龄和种族/民族的情况下，检查了特定 SEP 特征下 IBC 与非 IBC 的比值比（OR）。
IBC 的发病率随着 SEP 的降低而普遍升高，而非 IBC 则相反。HLM 结果表明，低 SEP 与 IBC 的高风险相关：贫困线以下比例最高（≥20%）与最低（<10%）人群[比值比（95%置信区间，CI）=1.25（1.09-1.43）]；未完成高中学业比例最高（>28.76%）与最低（≤15.99%）人群[比值比（95% CI）=1.25（1.10-1.42）]；以及用贫困-高中学业指数衡量的低 SEP 与高 SEP[比值比（95% CI）=1.26（1.11-1.44）]。
总体而言，乳腺癌与 SEP 呈正相关，而在本分析中，IBC 与 SEP 呈负相关。
需要开展研究，以了解 IBC 发病率差异，并开展干预以消除这些差异。
