Dutton D B
J Natl Med Assoc. 1979 Oct;71(10):945-54.
The average hematocrit levels of black children have been widely reported to be about two to three percent lower than those of white children. Until recently, the relative contributions of economic, nutritional, and genetic factors to these differences have been unspecified. Based on new evidence and reanalysis of past data, however, some investigators now argue that genetic differences exist which transcend economic status. Separate screening standards are thus recommended for black children-standards which would define fewer as anemic. The present paper discusses methodological inadequacies in the evidence supporting the separate standards argument, focusing on the skewed economic distributions by race which suggest economic disparities within the racial subgroups compared. Findings are presented from a study of children in Washington, DC, to illustrate the role of particular risk factors known to be differentially distributed by income (eg, multiparity, birthweight, source of medical care). These factors are associated with varying hematocrit levels, even among blacks, and they also appear to account for a large part of the black-white hematocrit differentials. Study findings cast doubt on conclusions about the genetic basis of hematocrit differences and suggest that, without better evidence, it would be inappropriate to adopt lower standards for blacks in screening for anemia.
据广泛报道，黑人儿童的平均血细胞比容水平比白人儿童低约2%至3%。直到最近，经济、营养和遗传因素对这些差异的相对贡献仍不明确。然而，基于新的证据和对过去数据的重新分析，一些研究人员现在认为存在超越经济地位的遗传差异。因此，建议为黑人儿童制定单独的筛查标准——这些标准会将贫血定义为更少的情况。本文讨论了支持单独标准论点的证据在方法上的不足之处，重点关注按种族划分的经济分布不均衡，这表明所比较的种族亚组内部存在经济差异。文中展示了对华盛顿特区儿童的一项研究结果，以说明已知按收入有差异分布的特定风险因素（如多胎妊娠、出生体重、医疗保健来源）的作用。这些因素与不同的血细胞比容水平相关，即使在黑人中也是如此，而且它们似乎也占了黑人和白人血细胞比容差异的很大一部分。研究结果对关于血细胞比容差异遗传基础的结论提出了质疑，并表明在没有更好证据的情况下，在贫血筛查中为黑人采用更低标准是不合适的。
