Heterogeneity in Hematological Parameters of High and Low Altitude Tibetan Populations

Figures & data

Figure 1 India map showing sampled area. The distance between Samad Rakchan and Bylakuppe is ~2320 km.

Abbreviation: masl, meters above sea level.

Table 1 Description of Anthropometric Parameters of the Subjects (n=168); Data is Expressed in Mean ± SD Format

Parameter	High Altitude	Low Altitude	Test, p-value
Age (years)	49.32 ± 13.70	67.15 ± 18.42	Mann-Whitney test, <0.0001
BMI (kg/m^2)	22.75 ± 3.67	25.28 ± 4.78	Unpaired t-test with Welch’s correction, 0.0004

Figure 2 Age distribution among (A) high altitude and (B) low altitude participants.

Abbreviations: HA, high altitude; LA, low altitude.

Table 2 Description of Various Hematological Parameters in the Subjects; Data is Expressed in Mean ± SD Format

Parameter	HA Male (n=23)	LA Male (n=46)	HA Female (n=23)	LA Female (n=43)	Test, p-value (HA Male vs LA Male); Test, p-value (HA Female vs LA Female)
WBC (cells/µL)	6957 ± 1788	6744 ± 1682	6743 ± 1938	7277 ± 1472	Mann-Whitney test, 0.7022; Unpaired t-test with Welch’s correction, 0.2565
RBC (10^6 cells/µL)	6.21 ± 0.74	4.45 ± 0.49	5.4 ± 0.40	4.19 ± 0.40	Mann-Whitney test, <0.0001; Unpaired t-test with Welch’s correction, <0.0001
HCT (%)	59.83 ± 6.89	44.57 ± 4.56	50.09 ± 3.6	42.5 ± 4.06	Unpaired t-test with Welch’s correction, <0.0001; Unpaired t-test with Welch’s correction, <0.0001
MCV (fL)	96.6 ± 8.06	100.5 ± 6.97	92.7 ± 6.17	101.5 ± 4.67	Mann-Whitney test, 0.0280; Unpaired t-test with Welch’s correction, <0.0001
MCH (pg/cell)	32.29 ± 2.51	30.27 ± 3.40	31.07 ± 1.97	30.04 ± 1.92	Mann-Whitney test, 0.0212; Mann Whitney test, 0.1347
MCHC (g/dL)	33.47 ± 1.92	30.07 ± 2.26	33.47 ± 1.99	29.58 ± 1.23	Mann-Whitney test, <0.0001; Unpaired t-test with Welch’s correction, <0.0001

Figure 3 Various hematological parameters of high and low altitude Tibetan males and females: (A) RBC, (B) HCT, (C) Hb, (D) MCV, (E) MCH and (F) MCHC. Blue and maroon horizontal lines represent mean ± SD. ****p <0.0001, *p = 0.01–0.05.

Abbreviations: HA, high altitude; LA, low altitude; RBC, red blood cell; HCT, hematocrit; Hb, hemoglobin concentration; MCV, mean corpuscular volume; MCH, mean corpuscular hemoglobin; MCHC, mean corpuscular hemoglobin concentration.

Table 3 Description of Serum EPO and Hb in the Subjects; Data is Expressed in Mean ± SD Format

Parameter	HA Male	LA Male	HA Female	LA Female	Test, p-value (HA Male vs LA Male); Test, p-value (HA Female vs LA Female)
EPO (mIU/mL)	13.3 ± 11.61 (n=21)	11.32 ± 7.77 (n=42)	13.21 ± 6.98 (n=21)	11.31 ± 7.63 (n=42)	Mann-Whitney test, 0.4826; Mann-Whitney test, 0.1283
Hb (g/dL)	20.01 ± 1.91 (n=41)	13.42 ± 1.75 (n=46)	16.97 ± 1.74 (n=38)	12.56 ± 1.19 (n=43)	Unpaired t-test with Welch’s correction, <0.0001; Unpaired t-test with Welch’s correction, <0.0001

Table 4 Description of BMI Among Participants Belonging to Three Different Age Categories; Data is Expressed in Mean ± SD Format

Age Category	BMI				Test, p-value (HA Male vs LA Male); Test, p-value (HA Female vs LA Female)
	HA Male	LA Male	HA Female	LA Female
17–40 years	20.46 ± 2.18 (n=13)	23.83 ± 7.25 (n=3)	24.34 ± 3.74 (n=9)	28.08 ± 5.35 (n=4)	Mann-Whitney test, 0.5643; Mann-Whitney test, 0.3119
41–60 years	21.66 ± 3.01 (n=22)	24.44 ± 5.18 (n=5)	23.83 ± 3.78 (n=19)	25.98 ± 3.86 (n=10)	Mann-Whitney test, 0.1413; Mann-Whitney test, 0.0915
61–80 years	24.33 ± 4.89 (n=6)	23.35 ± 4.50 (n=22)	23.7 ± 4.08 (n=10)	28.88 ± 4.24 (n=8)	Mann-Whitney test, 0.7745; Mann-Whitney test, 0.0143

Table 5 Description of Hemoglobin Concentration Among Participants Belonging to Three Different Age Categories; Data is Expressed in Mean ± SD Format

Age Category	Hemoglobin Concentration (g/dl)				Test, p-value (HA Male vs LA Male); Test, p-value (HA Female vs LA Female)
	HA Male	LA Male	HA Female	LA Female
17–40 years	19.78 ± 1.7 (n=13)	13.9 ± 0.49 (n=4)	16.28 ± 1.39 (n=9)	12.3 ± 0.44 (n=4)	Mann-Whitney test, 0.0008; Mann-Whitney test, 0.0028
41–60 years	20.4 ± 1.87 (n=22)	15.24 ± 1.69 (n=5)	17.26 ± 1.90 (n=19)	12.79 ± 1.04 (n=16)	Mann-Whitney test, <0.0001; Mann-Whitney test, <0.0001
61–80 years	19.08 ± 2.30 (n=6)	13.34 ± 1.59 (n=22)	17.05 ± 1.69 (10)	12.56 ± 1.41 (14)	Mann-Whitney test, <0.0001; Mann-Whitney test, <0.0001

Figure 4 Hemoglobin concentration (Hb) among age-categorized participants: (A) in the age range of 17–40 years, (B) 41–60 years, (C) 61–80 years. ****p <0.0001, ***p = 0.0001–0.001, **p = 0.001–0.01. Blue and maroon horizontal lines represent mean ± SD.

Abbreviations: HA, high altitude; LA, low altitude.

Figure 5 Distribution of serum erythropoietin (EPO) level among participants.

Abbreviations: HA, high altitude; LA, low altitude.