Clark M, Royal J, Seeler R
Division of Ambulatory Pediatrics, Cook County Children's Hospital, Chicago.
Pediatrics. 1988 Feb;81(2):247-54.
Microcytic anemia, long considered an effect of lead poisoning, may in fact result from coexisting iron deficiency. In this study, how RBC size, hemoglobin, and zinc protoporphyrin vary as a function of iron status in a group of children with high lead levels was examined. Charts of all children (N = 51) admitted to Cook County Hospital for treatment of lead poisoning in 1981 to 1983 were reviewed for data on age, blood lead level, hemoglobin concentration, MCV, transferrin saturation and zinc protoporphyrin level. The mean lead level was 86 micrograms/dL and the range was 63 to 190 micrograms/dL. Children with transferrin saturation values less than 7% had a mean MCV of 56 microL, hemoglobin of 8.9 g/dL, and zinc protoporphyrin of 693 micrograms/dL; for those with saturations of 7% to 16%, the values were 61 microL, 10.1 g/dL, and 581 micrograms/dL, respectively; the children with saturations greater than 16% had normal mean MCVs and hemoglobin concentrations (74 microL and 11.4 g/dL) and a mean zinc protoporphyrin value of 240 micrograms/dL (P less than .0005). Multiple linear regression was used to correct for effect of age, and transferrin saturation remained the most important predictor of MCV, hemoglobin, and zinc protoporphyrin levels; the addition of lead did not improve the models. Results of this study suggest that iron deficiency is strongly associated with some of the observed toxicities of lead. Also, lead poisoning can exist without producing microcytosis or anemia, and zinc protoporphyrin concentration may not be a sensitive indicator of lead level in the absence of iron deficiency.
小细胞性贫血长期以来被认为是铅中毒的一种后果，而实际上可能是由并存的缺铁所致。在本研究中，对一组血铅水平较高的儿童，研究了红细胞大小、血红蛋白和锌原卟啉如何随铁状态而变化。回顾了1981年至1983年入住库克县医院治疗铅中毒的所有儿童（N = 51）的病历，以获取年龄、血铅水平、血红蛋白浓度、平均红细胞体积（MCV）、转铁蛋白饱和度和锌原卟啉水平的数据。平均铅水平为86微克/分升，范围为63至190微克/分升。转铁蛋白饱和度值低于7%的儿童，平均MCV为56微升，血红蛋白为8.9克/分升，锌原卟啉为693微克/分升；饱和度为7%至16%的儿童，相应的值分别为61微升、10.1克/分升和581微克/分升；饱和度大于16%的儿童，平均MCV和血红蛋白浓度正常（分别为74微升和11.4克/分升），平均锌原卟啉值为240微克/分升（P小于0.0005）。采用多元线性回归校正年龄的影响，转铁蛋白饱和度仍然是MCV、血红蛋白和锌原卟啉水平的最重要预测指标；加入铅并没有改善模型。本研究结果表明，缺铁与一些观察到的铅毒性密切相关。此外，铅中毒可能存在而不产生小红细胞症或贫血，并且在没有缺铁的情况下，锌原卟啉浓度可能不是铅水平的敏感指标。
