Nutrition and Health Sciences Program, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA, USA.
J Nutr. 2012 Jan;142(1):105-11. doi: 10.3945/jn.111.146316. Epub 2011 Dec 7.
The assessment of iron status where infections are common is complicated by the effects of inflammation on iron indicators and in this study we compared approaches that adjust for this influence. Blood was collected in 680 children (aged 6-35 mo) and indicators of iron status [(hemoglobin (Hb), zinc protoporphyrin (ZP), ferritin, transferrin receptor (TfR), and TfR/ferritin index)] and subclinical inflammation [(the acute phase proteins (APP) C-reactive protein (CRP), and α-1-acid glycoprotein (AGP)] were determined. Malaria parasitemia was assessed. Subclinical inflammation was defined as CRP >5 mg/L and/or AGP >1 g/L). Four groups were defined based on APP levels: reference (normal CRP and AGP), incubation (raised CRP and normal AGP), early convalescence (raised CRP and AGP), and late convalescence (normal CRP and raised AGP). Correction factors (CF) were estimated as the ratios of geometric means of iron indicators to the reference group of those for each inflammation group. Corrected values of iron indicators within inflammation groups were obtained by multiplying values by their respective group CF. CRP correlated with AGP (r = 0.65; P < 0.001), ferritin (r = 0.38; P < 0.001), Hb (r = -0.27; P < 0.001), and ZP (r = 0.16; P < 0.001); AGP was correlated with ferritin (r = 0.39; P < 0.001), Hb (r = -0.29; P < 0.001), and ZP (r = 0.24; P < 0.001). Use of CF to adjust for inflammation increased the prevalence of ID based on ferritin < 12 μg/L by 34% (from 27 to 41%). Applying the CF strengthened the expected relationship between Hb and ferritin (r = 0.10; P = 0.013 vs. r = 0.20; P < 0.001, before and after adjustment, respectively). Although the use of CF to adjust for inflammation appears indicated, further work is needed to confirm that this approach improves the accuracy of assessment of ID.
在感染很常见的情况下，铁状态的评估会受到炎症对铁指标的影响，因此在这项研究中，我们比较了几种调整这种影响的方法。在 680 名 6-35 月龄的儿童中采集血液，并测定铁状态指标[血红蛋白（Hb）、锌原卟啉（ZP）、铁蛋白、转铁蛋白受体（TfR）和 TfR/铁蛋白指数]和亚临床炎症指标[急性时相蛋白（APP）C 反应蛋白（CRP）和α-1-酸性糖蛋白（AGP）]。评估疟疾寄生虫血症。将亚临床炎症定义为 CRP >5 mg/L 和/或 AGP >1 g/L）。根据 APP 水平将儿童分为四组：参考组（CRP 和 AGP 正常）、孵育组（CRP 升高而 AGP 正常）、早期恢复期组（CRP 和 AGP 升高）和晚期恢复期组（CRP 正常而 AGP 升高）。校正因子（CF）估计为每个炎症组的铁指标的几何平均值与参考组的比值。通过将各炎症组的值乘以各自的组 CF 来获得铁指标的校正值。CRP 与 AGP（r = 0.65；P < 0.001）、铁蛋白（r = 0.38；P < 0.001）、Hb（r = -0.27；P < 0.001）和 ZP（r = 0.16；P < 0.001）相关；AGP 与铁蛋白（r = 0.39；P < 0.001）、Hb（r = -0.29；P < 0.001）和 ZP（r = 0.24；P < 0.001）相关。使用 CF 调整炎症会使根据铁蛋白 < 12μg/L 诊断 ID 的患病率增加 34%（从 27%增加到 41%）。应用 CF 可增强 Hb 和铁蛋白之间的预期关系（r = 0.10；P = 0.013 比 r = 0.20；P < 0.001，分别在调整前后）。尽管使用 CF 来调整炎症似乎是合适的，但还需要进一步的工作来确认这种方法是否可以提高 ID 评估的准确性。
