探討血小板捐血人的長期鐵蛋白變化趨勢

Abstract

鐵是人體必需的營養素，根據聯合國的報告，缺鐵是開發中國家與富裕國家相同面對的營養與公共衛生問題。近年來，捐血可能會因血液的流失，造成捐血者貧血的議題已受到美國血庫協會的重視。台灣血液基金會於2009年至2013年，曾實施每5個月監測分離術血小板捐血者的鐵蛋白值，累積的資料尚未做統整分析，值得做進一步的研究。 本研究藉由收集5,127位進行鐵蛋白值監測個案的性別、年齡、鐵蛋白值、BMI、血紅素值及平均紅血球體積數據，計算其敘述統計(如平均值、標準誤、中位數)以了解這些資料的分布概況，並以t檢定(t test)比較男女各變項平均值的差異；再以性別與年齡50歲分層，比較不同的捐血頻率¬是否對鐵蛋白的影響有差異。若依照台灣血液基金會之規定，將2次鐵蛋白檢測的時間範圍限制在150~160天的間隔，再依間隔中間的捐血次數將所有個案資料分為0次、1~3次、4~6次、7~9次及10次以上共五組，比較五組的「前」「後」測鐵蛋白改變量有無差異，結果發現高捐血頻率組的鐵蛋白改變量最大。之後又針對高頻率(半年捐血10次以上組)捐血者進行縱貫分析，發現長期持續的高頻率捐血的確造成體內鐵蛋白顯著下降，且初始鐵蛋白的高低對鐵蛋白的改變量亦有差異。本研究續以多元回歸分析探討，進一步以廣義估計式建立本研究的重複測量結果預測鐵蛋白，統計分析使用SAS(9.4版)及SAS EG(6.1版)統計軟體執行個案敘述統計及推論統計分析。 本研究分別以鐵蛋白改變量及鐵蛋白建立兩種模式。結果發現性別、捐血頻率、初始鐵蛋白及BMI都是鐵蛋白顯著預測因子(p值皆<0.05)。 本研究發現本國的血小板捐血者在近半年的捐血間隔下，捐血次數越高，鐵蛋白值下降越多。而這種高頻率的血小板捐血者，持續捐一年後的體內鐵蛋白仍會下降，但下降情況趨緩；多元迴歸模式分析結果顯示，性別、捐血頻率、初始鐵蛋白及BMI對血小板捐血人的鐵蛋白有顯著影響，未來應可適度利用來建立捐血者之的體內鐵蛋白質的預測，以初步評估捐血人是否適合進行捐血。

Iron is a necessary nutrient for the human body, according to the United Nations report, iron deficiency is a public health problem in many countries. In recent years, the iron-deficiency anemia due to blood donation has attracted great attention. From 2009 to 2013, Taiwan Blood Service Foundation conducted a program to monitor the ferritin levels of platelet blood donors. This huge dataset had not yet been analyzed. In this study, we collected 5,127 cases whose ferritin levels have been monitored more than twice with an interval of detection in 150-160 days. The summary statistics, such as mean value, standard error and median, were then calculated for variables including sex, age, BMI, ferritin value, hemoglobin value and mean corpuscular volume. The difference between mean values of different genders was compared with t test. The blood donations frequency was categorized into five groups: 0 times, 1 to 3 times, 4 to 6 times, 7 to 9 times and more than 10 times. The result indicates that the group with the highest frequency (more than 10 times) has the lowest ferritin level. In this study, two multiple regression models with Generalized estimating equation (GEE) were explored, i.e. the ferritin changes model and the ferritin model. The multiple regression analysis with GEE identified that gender, donation frequency, initial ferritin value and BMI were all significant predictors for ferritin level (all p’s<0.05). All data were analyzed for descriptive and statistical analysis using the Statistical Analysis System (SAS). This study identifies that the higher the frequency of blood donation, the more the decline in ferritin. Such decreasing pattern remains for the high frequency group even after a year, but with a slower rate, if they continue to donate. Furthermore, to predict future ferritin level, the gender, donation frequency, initial ferritin value and BMI could be used to predict future ferritin levels, and serve as information for whether the blood donation will further induce the deficiency.