According to the World Health Organization, the cutoff hemoglobin (Hb) value for defining anemia is 11 g/dL in preschool-aged children, and Hb measurements should be corrected above an altitude of 1000 meters. This study sought to determine the altitude at which the Hb value increases compared with that at sea level, Hb changes with age and region in Peru, the prevalence of anemia according to three different models used to correct Hb for altitude, and the association of the Hb value with stunting. Two individual-based Peruvian national databases were analyzed. Hb increased from an altitude of 375 meters. Hb concentration was lower at younger ages and higher at older ages. The increase in Hb with increasing altitude was lower in southern Peru. Implementing the different models for Hb measurement correction resulted in a higher and lower prevalence of anemia at altitudes >2500 and <2500 m, respectively, using the CDC adjustment. In children aged 6-23 months, the rate of stunting was lower in those with an Hb level of 10-12 g/dL (including mild anemia). In conclusion, the adjustment of Hb values for altitude should be considered before 1000 m and reference ranges should be adjusted to smaller groups of children instead of the same reference range for children aged 6-59 months.

中文翻译：

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秘鲁学龄前儿童血红蛋白水平随年龄和海拔的变化：对两个基于个人的国家数据库的评估

根据世界卫生组织的规定，学龄前儿童定义贫血的临界血红蛋白 (Hb) 值为 11 g/dL，应在海拔 1000 米以上校正 Hb 测量值。本研究试图确定 Hb 值与海平面相比升高的海拔高度、秘鲁 Hb 随年龄和地区的变化、根据用于校正 Hb 海拔高度的三种不同模型的贫血患病率以及发育迟缓的 Hb 值。分析了两个基于个人的秘鲁国家数据库。Hb 从海拔 375 米开始升高。Hb 浓度在年轻时较低，而在老年时较高。在秘鲁南部，Hb 随海拔升高而增加的幅度较低。使用 CDC 调整，实施不同的 Hb 测量校正模型分别导致海拔 > 2500 和 < 2500 m 的贫血患病率更高和更低。在 6-23 个月大的儿童中，Hb 水平在 10-12 g/dL（包括轻度贫血）的儿童发育迟缓率较低。总之，应考虑在 1000 米之前调整 Hb 值，并且应针对较小的儿童群体调整参考范围，而不是针对 6-59 个月的儿童进行相同的参考范围。