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ORIGINAL ARTICLE
Year : 2006  |  Volume : 13  |  Issue : 1  |  Page : 35-40  

Pattern of haemoglobin among high and low altitude children of Southwestern Saudi Arabia


Department of Physiology, College of Medicine, King Khalid University, Abha, Saudi Arabia

Date of Web Publication28-Jun-2012

Correspondence Address:
Fahaid H Al-Hashem
Chairman, Department of Physiology, College of Medicine, King Khalid University, P.O. Box 641, Abha
Saudi Arabia
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Source of Support: None, Conflict of Interest: None


PMID: 23012101

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   Abstract 

Objective: To determine the levels of haemoglobin and to study some of its correlates in high and low altitude children of the Southwestern region of the kingdom of Saudi Arabia.
Methods: A cross-sectional study of 1331 Saudi children aged 1-15 years born and living permanently at high altitude (2800-3150 m above sea level) and 1185 Saudi children of comparable age born and living permanently at low altitude (500 m above sea level) was conducted. Their haemoglobin levels were estimated by using cyanmethaemoglobin method and correlated with age, weight and height.
Results: The mean haemoglobin levels were significantly greater in highland children compared with lowland children (p<0.0001 for both boys and girls). There were no significant differences in the mean haemoglobin levels between boys and girls at each study site. In both high and lowland children haemoglobin levels rose with age although lowland girls showed a drop beyond the age of 11-13 years and highland girls did not show any increase beyond the age of 9-11 years. In both boys and girls haemoglobin was found to be positively and significantly correlated with weight and height.
Conclusions: The difference in haemoglobin levels between high and lowland children was attributed to the combined effect of high altitude hypoxia and the higher incidence of tropical infections among lowland children.

Keywords: Haemoglobin, Children, Altitude


How to cite this article:
Al-Hashem FH. Pattern of haemoglobin among high and low altitude children of Southwestern Saudi Arabia. J Fam Community Med 2006;13:35-40

How to cite this URL:
Al-Hashem FH. Pattern of haemoglobin among high and low altitude children of Southwestern Saudi Arabia. J Fam Community Med [serial online] 2006 [cited 2020 Aug 8];13:35-40. Available from: http://www.jfcmonline.com/text.asp?2006/13/1/35/97572


   Introduction Top


Certain biochemical, physiological and micro-anatomical responses occur during acclimatization and adaptation to chronic hypoxia of high altitude. [1] Among these responses are changes in haemoglobin levels. [2] Several studies have been carried out in different high altitude populations throughout the world. [3],[4],[6] However, no study has dealt specifically with the Southwestern highlands of the Kingdom of Saudi Arabia where both environmental factors and population genotypes differ widely from other studied areas.

The topography of the Asir Region in the Southwestern part of the Kingdom of Saudi Arabia varies from an altitude of 3150 m to sea level. [7] The region is, therefore, ideally situated to provide information on possible effects of altitude on haemoglobin levels. However, no carefully controlled study in children specific to this region has been reported. The present study was, therefore, undertaken to determine the levels of haemoglobin and some of its correlates in high and lowland children of the Southwestern region of the Kingdom of Saudi Arabia.


   Methods Top


The study was carried out at high and low altitude areas of the Asir region in the Southwestern part of the Kingdom of Saudi Arabia. Alsoda and the villages around Sabit Allia city were selected to represent the high altitude areas (2800-3150 m above sea level) while the villages around Mohyel city, situated at 500 m above sea level, represented low altitude areas. Environmental data on these areas are shown on [Table 1]. [7] Alsoda lies about 600 km south of Jeddah (the second largest city in the kingdom) and Sabit Allia is about 560 km south of Jeddah. Mohyel is in Tihama valley about 520 km south of Jeddah. The areas involved in the study had ready access to health facilities and enjoy an adequate diet comprising mainly of meat, chicken and rice. Potable water and electricity are also available in the two areas.
Table 1: Environmental data on the high and lowland of the study

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Data were collected from 1331 children aged 1-15 years who were born and permanently resided at a high altitude and 1185 children of comparable age born and permanent residents at low altitude. The children were selected from different age groups from different households. These numbers constituted about 90% of children registered in the health centers at high and low altitude. Each child was first subjected to a detailed clinical examination. Children in whom pathological conditions were detected by clinical examination as well as children with positive stool examination for pathogenic parasites were excluded from this study. All children sampled were Arabs and of Saudi nationality. All measurements were made at the health centers. This study was carried out in the period between 1998 and 2000.

For each child, age was calculated and recorded from birth certificates at the time of examination. For children under two years, the body weight was measured on a baby scale and the supine height was taken with a measuring board (Harpenden), and for children over two years the body weight was measured with an Avery beam weighing scale and the standing height was measured with a stadiometer (SECA). The weights of the children in minimal clothing were measured to the nearest 0.1kg and the heights and supine lengths were taken without shoes to the nearest 0.5cm.Venous blood samples were taken into heparinzed tubes to determine haemoglobin using cyanmethaemo-globin method. [8] The basis of this method is to dilute blood in a Darbkin's reagent which consists of potassium cyanide, potassium ferricyanide and sodium bicarbonate. Haemoglobin, methaemo-globin and carboxyhaemoglobin are all converted into cyanmethaemoglobin. A medium standard is provided and labeled with the concentration of haemoglobin. The absorbance of the cyanmethaemoglobin solution and the medium standard are then measured in a photoelectric colorimeter at a wavelength of 540 nm (to give maximum absorbance). The haemoglobin concentration is then computed as follows: Haemoglobin (gm/dl) = (absorbance of the test / absorbance of the standard) x concentration of the standard

To determine the effect of age on haemoglobin levels, the children were divided into different age groups. [Table 2] shows the number in each age group by sex.
Table 2: The number of children in each age group by sex

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At different stages of the study, the collected data were compiled and fed into an IBM computer. SPSS package version 10 was used for standard statistical analysis including multiple regression. Student's T-test was used to determine statistical significance. P<0.05 was considered statistically significant.


   Results Top


[Table 3] shows the mean ages and some of the characteristics of high and lowland children by sex. The study was confined to children from 1 to 15 years. Compared with lowland children, highland children were found to be significantly heavier and taller. This was true for both boys and girls. When the two sexes at the same altitude were compared, boys were found to be significantly lighter and shorter than their respective girls (p<0.001 and < 0.01 respectively).

The mean haemoglobin levels in high and lowland children by sex are shown in [Table 4]. The mean haemoglobin levels were significantly higher in highland children than their counterparts living in the lowland areas. This was true for both boys and girls (p<0.0001). At both altitudes, there were no significant differences in the mean haemoglobin levels between boys and girls.
Table 3: Mean values + standard deviations of age, weight and height

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Table 4: Mean + standard deviations of hemoglobin (Hb) levels of Saudi high and lowland children by sex

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[Figure 1] shows the relationship between haemoglobin levels and age of children living at high altitudes and those at low altitudes. The haemoglobin level in lowland children increased steadily with an increase in age, from 9.9 g/dl in the youngest group to 12.1 g/dl in the oldest and from 9.6 g/dl in the youngest group to 11.8 g/dl in the age group 11-13 in boys and girls respectively. Similar trends were seen in highland children except that the level of increase was very slight. In highland boys the haemoglobin increased from 12.9 g/dl in the youngest group to 13.8 g/dl in the oldest group, and in highland girls the increase was from 12.9 g/dl in the youngest to 13.5 g/dl in the 9-11year-olds, after which there was no increase with increasing age. In all age groups, there were no significant differences in haemoglobin levels between boys and girls at each study site except in the age group 13-15 years where lowland boys tended to have significantly higher haemoglobin levels than their girl counterparts (p< 0.0005).
Figure 1: Relationship between mean hemoglobin levels and age in high and lowlands boys and girls

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Multiple regression analysis was done to assess the impact of weight and height on haemoglobin levels in the children. This was done separately for boys and girls. [Table 5] indicates that the multiple linear regression models (haemoglobin as a function of weight and height) were statistically valid and that the linear fits were adequate. The multiple regression equations that describe the data more efficiently are: Haemoglobin =10.1+ (6.03 x weight) + (0.01 x height) for boys and Haemoglobin= 10 + (0.02 x weight) + (0.01 x height) for girls.
Table 5: The multiple linear regression models (hemoglobin as a function of weight and height) of Saudi high and lowland children by sex

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In both boys and girls at high and low altitudes, the regression coefficients indicated that weight and height were significant contributors to haemoglobin levels (for boys p<0.003 and for girls p<0.005 for both weight and height).


   Discussion Top


The results presented in this paper have shown that highland children of the Southwestern heights of the Kingdom of Saudi Arabia have significantly higher haemoglobin levels than their counterparts of comparable age living in the lowlands. In addition to altitude interpopulation, differences in haemoglobin levels are sometimes partly due to racial or dietary factors [9],[10] or due to adaptive evolutionary changes. [11] In this study, the racial and dietary factors were eliminated by using low altitude children of the same ethnic background and the same dietary habits as control. Thus, the factor that appears to be at work in this situation is environmental. High altitude hypoxia is known to cause an increase in erythropoietin level which in turn increases red cell mass and hence haemoglobin levels. [12] In addition, and because of the tropical nature of the studied area, the lowland children experience continuous high temperatures and therefore have a higher incidence of tropical infections, namely, leishmaniasis [13] and malaria [14] which are known to cause a fall in haemoglobin levels. [15],[16] On the other hand, highland children are exposed to cold weather which tends to reduce tropical infections. It is most likely, therefore, that the differences in haemoglobin levels between high and lowland children were related to the combined effects of high altitude hypoxia and the beneficial effects of the prevailing milder environmental conditions on the health of children at high altitude.

The mean levels of haemoglobin obtained in this study for highland children were not much different from those obtained by Khan et al [17] from Abha city which lies in the same area of study (13.8 g/dl) although the sample in that study included both Saudi and non Saudi children who were not permanent residents of the area of study. For lowland children the levels obtained were lower than what had been reported by Ghafouri et al [18] from Jeddah which lies at sea level (13 g/dl). However their results were obtained from an urban area and did not include children from 1-5 years.

One consistent trend in the literature on haemoglobin in children is the tendency for haemoglobin to increase with increasing age. [17],[19],[20] This trend was also apparent for both high and lowland children (see results). However, the drop in haemoglobin levels seen in lowland girls after the age of 11-13 years may be due to the initiation of menstruation. This drop was, however, not seen in highland girls. Instead the haemoglobin levels were fairly leveled from the age of 9-11 years to the end of the study period. Taking into consideration that highland girls were heavier than lowland girls and in view of the strong relationship between body weight and the onset of menarche, [21] it is possible that highland girls had begun their menarche at an earlier age of 9-11 years and the effect of this on haemoglobin levels was opposed by the hypoxic effect of high altitude. The effect of age on haemoglobin levels in children was thought to be due to the fact that children in the first few years of life have a negative iron balance because only less than 10% of the dietary iron is absorbed. [20] In addition, child nutrient habit is usually low in iron, but with increasing age this habit gradually improves with the introduction of adult food which is rich in iron. [20]

Another finding of this study is the absence of significant differences in haemoglobin levels between boys and girls at either altitude before puberty. This finding agrees with observations from some parts of the world [6],[22] but at variance with reports from Jeddah [18] and Jamaica. [23] The investigators in these areas found significant differences in haemoglobin levels between boys and girls aged 5-11 years but no explanation for these differences were offered.

Finally, the impact of weight and height on haemoglobin levels in Saudi high and lowland children were identified. Tall heavy subjects tend to have higher values of haemoglobin levels. Similar patterns were observed in high and lowland men in the same area. [24] However, in this study, weight and height could only explain 10% of the variation in haemoglobin levels in highland and lowland children (R [2] adjusted = 0.1 for both boys and girls).

It is concluded that the significantly higher haemoglobin levels in highland children may be due in part to the polycythemic effect of chronic hypoxia of altitude and as well as the beneficial milder environmental conditions on the health of children.


   Acknowledgment Top


The author would like to thank all staff including administrators, physicians, technicians and nurses in primary health centers who assisted in this study.

 
   References Top

1.Ward PW, Millege JS, West JB. Altitude and haemoglobin concentration. In: Ward PW, Millege JS and West JB, eds. High altitude Medicine and Physiology. London: Chapman and Hall, 1989; 170-1.  Back to cited text no. 1
    
2.Penaloza D, Sime F, Ruiz L. Cor pulmonale in chronic mountain sickness; Present Concept of Mong's Disease. In: Porter R and Knight J, eds. High Altitude Physiology. London: Churchill Livingstone, 1971; 41-60.  Back to cited text no. 2
    
3.Villafuerte FC, Cardenas R, Monge CC. Optimal hemoglobin concentration and high altitude: a theoretical approach for Andean men at rest. J Appl Physiol 2004; 96(5):1581-8.  Back to cited text no. 3
    
4.Miao G. Normal reference value of hemoglobin of infant girls and altitude in China. Arch Med Res 2004; 35(1): 87-90.  Back to cited text no. 4
    
5.Beal CM, Brittenham GM, Strohl KP, Blangero J, Williams-Blangero S, Goldstein MC, et al. Hemoglobin concentration of high-altitude Tibetans and Bolivian Aymara. Am J Phys Anthropol 1998; 106(3):385-400.  Back to cited text no. 5
    
6.Leon-Velarde F, Gamboa A, Chuquiza JA, Esteba WA, Rivera-Chira M, Monge CC. Hematological parameters in high altitude residents living at 4355, 4660 and 5500 meters above sea level . High Altitude Medicine and Biology 2000; 1(2): 97-104.   Back to cited text no. 6
    
7.Climate Atlas of Saudi Arabia. Riyadh, Saudi Arabia: Ministry of Agriculture and Water, 1988.  Back to cited text no. 7
    
8.Dacie JV, Lewis SM. Estimation of haemoglobin by Cyanmethaemoglobin method. In: Dacie JV and Lewis SM, eds. Practical haematology 5th edition. London: Churchill Livingstone, 1975; 32-4.  Back to cited text no. 8
    
9.Dallman PR, Barr GD, Allen CM, Shinefield HT. Hemoglobin concentration in white, black and oriental children: Is there a need for separate criteria in screening for anemia? Am J Clin Nutr 1981; 31:377-80.  Back to cited text no. 9
    
10.Nicklas TA, Frank GC, Webber LS, Zinkgraf SA, Cresanta JL, Gatewood LC, Berenson GS. Racial contrasts in hemoglobin levels and dietary patterns related to hematopoiesis in children: the Bogalusa Heart Study. Am J Pub Hlth 1987; 77 (10):1320-3.   Back to cited text no. 10
    
11.Adams WH, Strang LJ. Hemoglobin levels in persons Tibetan ancestry living at high altitude .Proc Soc Exptl Biol Med 1975; 149:1036-9.  Back to cited text no. 11
    
12.Reynafarje C. Physiological patterns: Hematological aspects. In: life at high altitude, Scientific publication no. 140. Washington: Pan American Health Organization, 1966; 32-32.  Back to cited text no. 12
    
13.Buttiker W, Al-Ayed IH, Al-Wabil AH, Assalhy HS, Rashed AM, Shareffi OM.. Medical and Applied Zoology in Saudi Arabia. A preliminary study on leishmaniasis in two areas of Asir region. In: Fauna of Saudi Arabia vol 4, Wiltmer W and Buttiker W, eds. Jeddah: Meteorology and Environmental protection Agency 1982; 509-19.   Back to cited text no. 13
    
14.Malik GM, Seidi O, El-Taher A, Mohammed A. Clinical aspects of malaria in the Asir region, Saudi Arabia. Ann Saudi Med 1998; 18(1): 15-7.   Back to cited text no. 14
    
15.Geddes AM, Bryceson AD, Thin RN. Diseases due to infection. In: Edwards CR and Bouchier IA, editors. Davidson's Principles and Practice of Medicine . A text book for students and doctors.16th edition. London: Churchill Livingstone, 1991;150-4.   Back to cited text no. 15
    
16.Akhwale W.S, Lum JK, Kaneko A, Eto H, Obonyo C, Bjorkman, Eto H, et al. Anemia and malaria at different altitudes in the Western high lands of Kenya. Acta Tropica 2004; 91: 167-75.  Back to cited text no. 16
    
17.Khan MU, Amir SE, Aggerwal S. Hemoglobin levels and blood groups in persons living at a high altitude. Ann Saudi Med 1989; 9 (5):458-62.  Back to cited text no. 17
    
18.Ghafouri HM, Alfares AM, Islam SI, Ahmed AO, Jan MY. Haematological reference values assessed from birth to adolescence in Saudi subjects in the area of Jeddah. Saudi Med J 1987; 8 (6): 575-82.   Back to cited text no. 18
    
19.Weatherall DJ. Disorders of the blood. In: Weatherall DJ, Ledingham JG and Warrell DA, editors. Oxford Textbook of Medicine, Volume 2, 3rd edition. London: Oxford Medical publications, 1989; 19.4-19.4   Back to cited text no. 19
    
20.Stockman JA Disease of the blood. In: Behrman RE, Kliegman RM, Nelson WA and Vaughan VC editors. Nelson text book of pediatrics. 14th edition. Philadelphia: W.B.Saunders, 1992; 1239-41.   Back to cited text no. 20
    
21.Frisch RE, McArthur JW. Menstrual cycles: fatness as a determinant of minimum weight for height necessary for their maintenance or onset. Science 1974; 185: 949-51.   Back to cited text no. 21
    
22.Garruto RM, Chin CT, Weitz CA, Liu JC, Liu RL, He X. Hematological differences during growth among Tibetans and Han Chinese born and raised at high altitude in Qinghai, China. A J Phys Anthropol 2003; 122 (2): 171-83.   Back to cited text no. 22
    
23.Serjeant GR, Grandison Y, Mason K, Serjeant B, Sewell A, Vaidya S . Haematological indices in normal Negro children: A Jamaican cohort from birth to five years. Clin Lab Haematol 1980; 2:169-78.   Back to cited text no. 23
    
24.Khalid MM, Ali ME, El-Kareb AO, Ahmed MK, Mahmoud MW. Anthropometric variables affecting hemoglobin levels in high and low altitude populations. Saudi Med J 1998; 19 (5):571-4.  Back to cited text no. 24
    


    Figures

  [Figure 1]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]



 

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