Cross-altitude analysis suggests a turning point at the elevation of 4,500 m for polycythemia prevalence in Tibetans
Cross-altitude analysis suggests a turning point at the elevation of 4,500 m for polycythemia prevalence in Tibetans
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跨海拔分析表明藏族红细胞增多症患病率在海拔4500 m出现转折点
DOI：
10.1002/ajh.24809
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发表时间：
2017
影响因子：
12.8
通讯作者：
Zhe
中科院分区：
文献类型：
--
作者：
Zhang Hui;He Yaoxi;Cui Chaoying;Ouzhuluobu;Baimakangzhuo;Duojizhuoma;Dejiquzong;Bianba;Gonggalanzi;Pan Yongyue;Qula;Kangmin;Cirenyangji;Baimayangji;Bai Caijuan;Guo Wei;Yangla;Peng Yi;Zhang Xiaoming;Xiang Kun;Yang Zhaohui;Liu Shiming;Tao Xiang;Gengdeng;Zhe
藏人是一个众所周知的遗传适应高海拔缺氧环境的例子。1遗传学和考古学资料都表明，藏族人从旧石器时代晚期（早在3万年前）就生活在青藏高原。2，3由于长期的自然选择，藏族人在低氧相关基因（如EPAS 1和EGLN 1）中积累了许多适应性突变，4-8尽管这些适应性突变在藏族人群中尚未固定。高原的平均海拔约为4，000米，约85%的藏人生活在海拔2，500米至4，500米之间的地区，只有6.2%的人生活在4，500米以上，这意味着极端海拔（> 4，500米）对藏人来说可能是一个挑战。据了解，藏族人血红蛋白（Hb）浓度相对较低，可以保护他们免受红细胞增多症（红细胞过度生成）的影响，这被认为是高海拔地区的一种迟钝的生理反应。相比之下，低地人长时间暴露于低压缺氧通常会导致红细胞增多症，这会增加心脏病发作、中风和妊娠期间胎儿丢失的风险。[9]总的来说，与生活在西藏的汉族移民相比，当地藏族人的血红蛋白浓度相对较低，血红蛋白浓度与海拔高度呈线性相关。10-12提出了“青海CMS评分”用于慢性高原病（CMS）的诊断，其中女性Hb 190 g/L或男性Hb 210 g/L作为高原红细胞增多症的诊断标准之一。13然而，以前的血红蛋白研究都依赖于线性模型，海拔的人口覆盖范围有限，特别是那些来自极端海拔（> 4 500米）的人口。此外，没有进行详细的分析，看看血红蛋白浓度是否会偏离线性预测在一定的高度。
Tibetans are a well-known example of genetic adaptation to hypoxic environments at high altitude. 1 Both genetic and archeological data suggest that Tibetans have been living at the Qinghai-Tibetan plateau since late Paleolithic time (as early as 30,000 years ago). 2, 3 Due to long-time natural selection, Tibetans have accumulated many adaptive mutations in the hypoxia-related genes (eg, EPAS1 and EGLN1), 4–8 though these adaptive mutations have not been fixed in Tibetan populations. The average elevation of the plateau is about 4,000 m, and about 85% Tibetans live in areas with elevations between 2,500 m and 4,500 m, and only 6.2% above 4,500 m, 1 implicating that the extreme altitude (> 4,500 m) could be a challenge to Tibetans. It is understood that the relatively low hemoglobin (Hb) concentration in Tibetans protects them from polycythemia (red cell overproduction), regarded as a blunted physiological response at high altitude. In contrast, the prolonged exposure of lowlanders to hypobaric hypoxia usually leads to polycythemia, which increases the risk of heart attack, stroke, and fetal loss during pregnancy. 9 In general, native Tibetans showed relatively lower Hb concentration compared with Han Chinese immigrants living in Tibet, and there was a linear correlation of Hb concentration with altitude. 10–12 The “Qinghai CMS score” was proposed for diagnosis of chronic mountain sickness (CMS), in which a value of Hb 190 g/L in females or Hb 210 g/L in males was taken as one of the diagnostic criterion for high altitude polycythemia. 13 However, previous studies of Hb were all relied on a linear model and population coverage of altitude was limited, especially those populations from the extreme altitude (> 4,500 m). In addition, no detailed analysis was performed to see if Hb concentration would deviate from the linear prediction at certain altitude.