Effect of Altitude on Hemoglobin and Red Blood Cell Indices in Adults in Different Regions of Saudi Arabia

Abstract

Purpose Complete blood count (CBC) is a commonly used blood test for health checks. This study was conducted to compare CBC from two different altitudes and from sea-level populations in order to suggest correction factor for altitude-related increment on the hemoglobin and red blood cell indices. Patients and Methods In this retrospective lab records study, large datasets of CBCs over 5-year period were screened from three different regions of Saudi Arabia, Jeddah (a coastal city), Taif City located at 1879 m above sea level, and Abha City at located 2270 m above sea level. Descriptive analysis and significance testing of the CBC variables at different altitude were compared. Results A total of 57,059 participants were included for final analysis. Mean hemoglobin (Hb) concentration (g/dL) was 14.81 for men and 13.77 for women at sea level, whereas Hb concentrations were 15.35 and 14.19 for men and women residing at Taif City, respectively, and 15.40 and 14.71 for men and women at Abha City, respectively. Hemoglobin and other red cell indices were significantly different among men and women across different altitude, except for mean corpuscular volume (MCV). The MCV 95 th percentile range was lower at sea level and both altitudes as compared to current reference range (76–91 fL vs 81–98 fL). Conclusion Although altitude-associated increment in Hb concentration was evident in both men and women, it was lower than as suggested by World Health Organization and Centers for Disease and Control. Results of this study can also be used to derive new CBC reference intervals for Saudi residents living at high altitude. A correction factor (ΔHb) of 0.30 g/dL per 1000 m altitude is suggested to be used in adult population living at high altitudes in Saudi Arabia which should help better define anemia and polycythemia at altitude.

Comparative Study of Complete Blood Count Between High-Altitude and Sea-Level Residents in West Saudi Arabia

“…For females, the results were equally revealing. [11,12]. These results elucidate the specific variations in females, adding a new dimension to our understanding of high-altitude acclimatization.…”

“…For males, the study found significant variations in all CBC parameters except NEU (P=0.8696), as shown in Table 3 . Specifically, the mean HGB for males was 169.8±10.63 in Taif and 144.6±13.96 in Jeddah (P<0.0001) while the mean PLT was 289.7±65.00 in Taif and 249.0±60.07 in Jeddah (P<0.0001) [ 8 - 11 ]. These findings highlight the distinct hematological adaptations in males in response to high altitude due to hypoxia [ 12 ].…”

“…Table 2 indicated significant results (P<0.0001) for BASO, HCT, HGB, MCH, MCHC, MPV, PLT [ 12 ], RDW, and WBC between the sea-level altitude and high altitude, while MONO, NEU, and RBC indicated no significance. The mean HGB for females was 138.5±7.600 in Taif and 128.6±8.050 in Jeddah (P<0.0001), and the mean PLT was 297.2±56.86 in Taif and 263.7±66.75 in Jeddah (P<0.0001) [ 11 , 12 ]. These results elucidate the specific variations in females, adding a new dimension to our understanding of high-altitude acclimatization.…”

“…The combined results for both males and females, as detailed in Table 1 , further emphasize the significant variations in CBC parameters. The mean WBC, RBC, and HBG, as shown in Figure 1A (HGB) [ 10 , 11 ], HCT and PLT, as shown in Figure 1B , polys, LYM, MONO, EOS, and BASOS were found to vary significantly between the two altitudes, reflecting the body's hypoxic response [ 9 ]. Specifically, the parameters MONO (P=0.1589) and NEU (P=0.2911) were not significant while all other parameters showed significant variations (P<0.0001).…”