Mei Zuguo, Namaste Sorrel Ml, Serdula Mary, Suchdev Parminder S, Rohner Fabian, Flores-Ayala Rafael, Addo O Yaw, Raiten Daniel J
Nutrition Branch, CDC, Atlanta, GA;
Strengthening Partnerships, Results, and Innovations in Nutrition Globally, Arlington, VA.
Am J Clin Nutr. 2017 Jul;106(Suppl 1):383S-389S. doi: 10.3945/ajcn.116.142307. Epub 2017 Jun 14.
Total body iron (TBI) that is calculated from ferritin and soluble transferrin receptor (sTfR) allows for the evaluation of the full range of iron status from deficiency to excess. However, both ferritin and sTfR are affected by inflammation and malaria, which may require a statistical adjustment. TBI has been used to assess iron status in the United States, but its use worldwide and in settings with inflammation has been limited. We examine whether inflammation-adjusted ferritin and sTfR concentrations affect TBI values and the prevalence of low TBI (<0 mg/kg) in preschool children (PSC) (age range: 6-59 mo) and women of reproductive age (WRA) (age range: 15-49 y). Cross-sectional data for PSC (8 surveys; = 8413) and WRA (4 surveys; = 4258) from the Biomarkers Reflecting the Inflammation and Nutritional Determinants of Anemia (BRINDA) project were analyzed individually and combined. TBI and the prevalence of low TBI were compared following 3 adjustment approaches for ferritin and sTfR: ) the exclusion of individuals with inflammation (C-reactive protein concentration >5 mg/L or α-1-acid glycoprotein concentration >1 g/L), ) the application of arithmetic correction factors, and ) the use of regression correction. Regardless of the method that was used to adjust ferritin and sTfR for inflammation, the adjusted mean TBI decreased in both PSC and WRA compared with unadjusted values. Subsequently, inflammation-adjusted TBI increased the prevalence of low TBI by a median of 4-14 percentage points (pps) in PSC and 1-3 pps in WRA compared with unadjusted TBI. The regression approach resulted in a greater median increase than was achieved with the exclusion or correction-factor approaches, and accounting for malaria in addition to inflammation did not have an added effect on the prevalence estimates. The prevalence of low TBI is underestimated if it is not adjusted by inflammation, particularly in children living in areas with a high prevalence of inflammation.
通过铁蛋白和可溶性转铁蛋白受体（sTfR）计算得出的全身铁含量（TBI）有助于评估从铁缺乏到铁过量的整个铁状态范围。然而，铁蛋白和sTfR都受炎症和疟疾的影响，这可能需要进行统计调整。TBI已在美国用于评估铁状态，但其在全球以及存在炎症的环境中的应用有限。我们研究了炎症校正后的铁蛋白和sTfR浓度是否会影响TBI值以及学龄前儿童（PSC）（年龄范围：6 - 59个月）和育龄妇女（WRA）（年龄范围：15 - 49岁）中低TBI（<0 mg/kg）的患病率。对来自反映贫血的炎症和营养决定因素（BRINDA）项目的PSC（8项调查；n = 8413）和WRA（4项调查；n = 4258）的横断面数据进行了单独分析和合并分析。针对铁蛋白和sTfR的3种调整方法如下，比较了TBI和低TBI的患病率：）排除有炎症的个体（C反应蛋白浓度>5 mg/L或α-1-酸性糖蛋白浓度>1 g/L），）应用算术校正因子，以及）使用回归校正。无论用于针对炎症调整铁蛋白和sTfR的方法如何，与未调整值相比，PSC和WRA中调整后的平均TBI均降低。随后，与未调整的TBI相比，炎症调整后的TBI使PSC中低TBI的患病率中位数增加了4 - 14个百分点（pps），使WRA中低TBI的患病率中位数增加了1 - 3个百分点。回归方法导致的中位数增加幅度大于排除或校正因子方法，并且除炎症外还考虑疟疾对患病率估计没有额外影响。如果不通过炎症进行调整，低TBI的患病率会被低估，特别是在炎症患病率高的地区生活的儿童中。
