乳癌及大腸癌篩檢不平等評估——反轉公平假說之檢視

Assessing inequalities in breast and colorectal cancer screening - testing the inverse equity hypothesis

目標：本研究探討乳癌及大腸癌篩檢利用之收入不平等，以及不平等與篩檢率之關係。方 法：本研究資料取自2001、2005、2009、2013年國民健康訪問調查，估計45或50歲至69歲乳癌 及大腸癌篩檢之與均等家戶收入關連之Erreygers集中指數（ECI）、相對不平等指數（RII）及 影響不平等因素解析。結果：乳房攝影及糞便潛血篩檢率自2001年之9.2%及10.1%分別上升至 2013年之46.1%及41.3%；並呈現收入愈高篩檢率愈高的現象。2001年最高收入群體之乳房攝影 使用率比最低收入群體多達近一倍（RII=0.984），但到2013年下降為多5.7%（RII=0.057）。 最高收入群體之糞便潛血檢查率比最低收入群體多40-60%（RII=0.377~0.634）。除了2013年乳 房攝影外，兩項篩檢之使用亦都集中於高收入群體（乳房攝影ECI=0.060~0.150；糞便潛血檢 查ECI=0.036~0.104）。免費政策實施前（2001、2005及2009年）收入都是影響篩檢不平等的重 要因素，但免費政策實施後（2013年）教育程度為最重要因素。結論：與「反轉公平假說」一 致，當篩檢率上升時，不同收入群體篩檢率差異愈小。提升篩檢率可縮減篩檢之社會不平等， 有助於緩和健康不平等。

Objectives: This study analyzed income-related inequalities in breast and colorectal cancer screening in Taiwan and the relationship between inequality and screening rate. Methods: We used data from the 2001, 2005, 2009, and 2013 National Health Interview Surveys. The Erreygers concentration indices (ECI) and relative inequality indices (RII) were calculated and ECIs were decomposed. Results: In 2001, 9.2% of participants reported undergoing mammography and 10.1% reported having a fecal occult blood test (FOBT) within the previous year. Those screening rates within the previous two years increased by 46.1% and 41.3% respectively in 2013 and showed income gradients. In 2001, mammography use by the highest-income group was nearly double that of the lowest-income group (RII=0.984), while that difference in 2013 fell by 5.7% (RII=0.057). Compared with the lowest-income group, the highest income group received 40- 60% more screening for FOBT (RII=0.377 to 0.634). Except for mammography in 2013, both mammography and FOBT were concentrated in the higher income group (ECI=0.06-0.15 for mammography; ECI=0.036-0.104 for FOBT). Before the national cancer screening programs in 2001, 2005 and 2009, income was the most important contributor to inequalities in the screening rate, while education accounted for the greatest contribution in 2013. Conclusions: Consistent with the “inverse equity hypothesis,” income-related inequalities in cancer screening decreased with higher screening rates. Therefore, an increased screening rate facilitates the reduction in inequality in cancer screening and addresses health inequalities.