The increase in hemoglobin concentration with altitude varies among human populations

Abstract

Decreased oxygen availability at high altitude requires physiological adjustments allowing for adequate tissue oxygenation. One such mechanism is a slow increase in the hemoglobin concentration ([Hb]) resulting in elevated [Hb] in high-altitude residents. Diagnosis of anemia at different altitudes requires reference values for [Hb]. Our aim was to establish such values based on published data of residents living at different altitudes by applying meta-analysis and multiple regressions. Results show that [Hb]is increased in all high-altitude residents. However, the magnitude of increase varies among the regions analyzed and among ethnic groups within a region. The highest increase was found in residents of the Andes (1 g/dL/1000 m), but this increment was smaller in all other regions of the world (0.6 g/dL/1000 m). While sufficient data exist for adult males and females showing that sex differences in [Hb] persist with altitude, data for infants, children, and pregnant women are incomplete preventing such analyses. Because WHO reference values were originally based on [Hb] of South American people, we conclude that individual reference values have to be defined for ethnic groups to reliably diagnose anemia and erythrocytosis in high-altitude residents. Future studies need to test their applicability for children of different ages and pregnant women.

The 2018 Global Research Expedition on Altitude Related Chronic Health (Global REACH) to Cerro de Pasco, Peru: an Experimental Overview

“…where 15% of men aged 30-39 years and 34% aged 60-69 years present with EE (Monge, Léon-Velarde, & Arregui, 1989). Additionally, a recent meta-analysis demonstrated that there are differences in the haemoglobin concentration between highlander populations (Gassmann et al, 2019) and, in agreement with previous reports (Beall, 2006(Beall, , 2007Beall et al, 2002), that meta-analysis indicated that Andean highlanders have higher haemoglobin concentration and haematocrit compared with other highlander populations (e.g. Sherpa and Ethiopians).…”

“…The Sherpa typically have lower haemoglobin (Hb) concentrations compared with other highlanders at similar altitudes, such as the Peruvian Quechuan (Beall, 2006; Gassmann et al., 2019). Some (Gilbert‐Kawai, Milledge, Grocott, & Martin, 2014; Tremblay, Hoiland, et al., 2018), but not all studies (Liu et al., 2016; Wang et al., 2018), indicate that Sherpa rely on enhanced blood flow and endothelial function to sustain convective oxygen delivery and also on cellular metabolic adaptations to use oxygen more efficiently (Horscroft et al., 2017).…”

Oxygen in Red Blood Cell Concentrates: Influence of Donors’ Characteristics and Blood Processing

“…Indeed, the effect of the altitude on Hb levels is well known. Magnitude of difference found is also impacted by the ethnic group and the sex (Gassmann et al, 2019).…”

Residential Altitude Associates With Endurance but Not Muscle Power in Young Swiss Men

“…Indeed, HIF-2 orchestrates expression of hundreds of hypoxia-induced genes. Even more so, as it has been shown that several ethnicities developed different adaptations when exposed to varying altitudes ( Gassmann et al, 2019 ).…”