High altitude hypoxia is believed to be experienced at elevations more than 2500 meters. A few studies have shed light on the biochemical aspects of high altitude acclimatization that profoundly included the subjects sojourning to the high altitude from low altitude and observation of the transient changes. However, information regarding the difference between the adapted people in high altitude and their counterpart, who reside in the low altitude are lacking. To address that issue, we have measured various hematological parameters and level of serum erythropoietin (EPO) in Tibetan population, who are residing in both high and low altitudes. We observed significant difference (p value < 0.0001) between high and low altitude Tibetan, in various hematological parameters, including red blood cells (RBC) count, hematocrit (HCT) or packed cell volume (PCV), and hemoglobin concentration (Hb). In case of mean corpuscular volume (MCV), significant difference was observed only in females (p value < 0.0001). Mean corpuscular hemoglobin concentration (MCHC) was significantly different between both males and females, but age was a potential confounder. There was no significant difference in serum EPO level between these two groups, either in males or females, which might be due to blunted erythropoietin response in the Tibetan population. We have also analyzed correlation between serum EPO with Hb and serum EPO with HCT and found no significant correlation. In multiple regression analysis, low altitude and male-gender showed significant impact on both Hb and HCT. In conclusion, our study suggests significant perturbation of hematological parameters, when native high altitude populations migrated to low altitude and inhabited for a long period.

中文翻译：

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高海拔和低海拔藏族人群的血液学参数

据信高海拔缺氧发生在海拔超过2500米的地方。一些研究揭示了高海拔适应的生物化学方面，深刻地包括了从低海拔升迁到高海拔并观察瞬态变化的对象。但是，缺乏有关高海拔适应人群与低海拔居住人群之间差异的信息。为了解决该问题，我们测量了居住在高海拔和低海拔地区的藏族人群的各种血液学参数和血清促红细胞生成素（EPO）水平。我们在各种血液学参数（包括红细胞（RBC）计数），高海拔和低海拔藏族之间观察到了显着差异（p值<0.0001）。血细胞比容（HCT）或堆积细胞体积（PCV）和血红蛋白浓度（Hb）。在平均红细胞体积（MCV）的情况下，仅在女性中观察到显着差异（p值<0.0001）。男性和女性的平均红细胞血红蛋白浓度（MCHC）均存在显着差异，但年龄是潜在的混杂因素。两组之间的血清EPO水平无明显差异，无论是男性还是女性，这可能是由于藏族人群促红细胞生成素反应迟钝所致。我们还分析了血清EPO与Hb和血清EPO与HCT之间的相关性，未发现显着相关性。在多元回归分析中，低海拔和男性性别对Hb和HCT都有显着影响。总而言之，我们的研究表明血液学参数存在明显的扰动，