Hemoglobin Levels and Blood Groups in Persons Living at a High Altitude

Transcription

1 Moslem Uddin Khan, PhD, MFCM; Serag El-Dine Amir, MB, BCh, MSc; Shashi Aggerwal, BSc(MLT) From the Department of Family and Community Medicine, King Saud University, College of Medicine, Abha Branch (Dr. Khan), and Shamasan Health Centre, Ministry of Health (Dr. Amir and Mrs. Aggerwal), Abha. Address reprint requests and correspondence to Dr. Khan: Department of Family and Community Medicine, King Saud University, College of Medicine, Abha Branch, P.O. Box 641, Abha, Saudi Arabia. Accepted for publication 18 January A study has been conducted to determine the hemoglobin norms and blood groups of the people living at a high altitude (2500 to 3000 meters above sea level). Hemoglobin levels and blood groups were obtained from healthy individuals coming for family registration with the primary health center. Hemoglobin was estimated by the cyanmethemoglobin method, and the ABO grouping system was used. Results showed that males had higher hemoglobin levels than females from the age of 15 years. From childhood to old age the mean value for males ranged from 130 to 163 g/l and for females from 128 to 150 g/l. In all, 33% had group A, 12% group B, 52% group O, and nearly 3% group AB. Only 8.4% had Rh-negative blood. Blood groups had no relation to hemoglobin levels. These findings may help physicians assess anemia in patients living at high altitudes and administrators responsible for procurement of specific blood groups for hospitals. MU Khan, S El-Dine Amir, S Aggerwal, Hemoglobin Levels and Blood Groups in Persons Living at a High Altitude. 1989; 9(5): A person is considered anemic when his or her hemoglobin level falls below two standard deviations from the mean for a normal population (140 g/l for men, 120 g/l for women) at sea level. 1 Physicians usually refer to hemoglobin levels more frequently than other hematologic characteristics for patient care. To determine hemoglobin reference values of the Saudi population, studies have been done by Sebai, 2 Hassan et al, 3 and others. A large fraction of the Saudi population lives at high altitudes. Their hemoglobin levels for assessing them as anemic or normal have not been determined adequately. A study done by Scott 4 was with a small group of male subjects and the altitude of the place was 745 meters; the levels obtained in this study cannot be used for comparison with all ages and sexes. The study done by Bacchus et al was at 1000-meter altitude. 5 Many southern region people, however, live at an altitude higher than 1000 meters. Whether blood group has any influence on hemoglobin level at a higher altitude is now known. In addition, although blood groups A and O are said to be most prevalent in Saudis, 2 studies taking a sufficient number of samples have not been done. This is essential in procuring specific types of blood from abroad for hospital emergencies. We, therefore, wanted to examine these issues anew in a healthy population living at an altitude of 2500 to 3000 meters above sea level in Abha, Saudi Arabia. Materials and Methods The study was done in Abha City, which is situated at an altitude of 2500 to 3000 meters above sea level. The

2 population is composed of Saudis, Egyptians, Yemenis, and other nationalities. Of the three primary health care centers in Abha, Shamasan Centre provides primary care for about 30% of the city's population. To avail themselves of health care facilities, families must register with the primary health care center. All members of the family are to present themselves for a health check-up and for laboratory investigations of stool, blood, and urine. The nurses of the center informed as many families as possible by visiting them to encourage and remind them to attend the center on particular dates for health check-up and registration. Family members were also reminded of appointments by telephone. They were examined by a physician and a dentist. Laboratory investigations were done by a medical technologist, and then a family file was opened for them. All ailments, treatment, outcome of illness, results of investigations, and pregnancies were recorded in the family file. We obtained the initially determined hemoglobin levels and the blood groups of all the family members examined. The investigations included all ages and both sexes. Incomplete reports and results of investigations on pregnant women were excluded. For estimation of hemoglobin levels the cyanmethemoglobin method has been used. 6 For grouping, ABO blood grouping has been followed. 7 For measuring the validity of differences, the simple chi-square test was applied. 8 Results Table 1 shows the distribution of hemoglobin levels of 1604 persons by age and sex. Of the male population, 29.9% had a hemoglobin level of 121 to 140 g/l; 35.4%, 141 to 160 g/l; and 28.3%, 161 to l80 g/l. In the female group, 43.4% had a hemoglobin level of 121 to 140 g/l; 39.7%, 141 to 160 g/l; and 6.7%, between 161 and 180 g/l. The differences in prevalence rates of hemoglobin levels of 121 to 140 g/l and 161 to 180 g/l between males and females were statistically signifcant. There was none with Hb level over 180 g/l. Table 1. Levels of hemoglobin by age, sex, and percentage of population. Age (y) Male Hb (g/l) Female Hb (g/l) Mean Mean Total % No. of subjects * * * The difference in prevalence rate of 121 to 140 g/l hemoglobin level between male and female subjects is significant (P < 0.01). The difference in prevalence rate of 161 to 180 g/l hemoglobin level between male and female subjects is significant (P < 0.001). In both males and females, adults had higher hemoglobin levels than children up to 14 years old. Male children up to 14 years old had higher hemoglobin levels than female children of the same age group. Of the male children 10 to 14 years old, 36.3% had moderately low hemoglobin levels (121 to 140 g/l), while 43.2% of the female children had the same hemoglobin level. Of male children of the same group, 54.0% had medium hemoglobin level (141 to 160 g/l), and 45% of the female children had such levels. In the age group 15 to 19 years, 90.6% of the males had a hemoglobin level equal or over 140 g/l, while only 55.7% of females had such a level. Overall, 28.3% of males and 6.7% of females had high hemoglobin levels (161 to 180 g/l). Figure 1 shows the 50th percentile distribution of hemoglobin levels (rounded to the nearest whole number) for male and female subjects by age. The 50th percentile level for all children, both male and female up to 9 years old, was 130 g/ L. It was the same (130 g/l) for females between 10 and 14 years old. From the age of 15 years upward,

3 the 50th percentile hemoglobin level for females was 150 g/l and for males 170 g/l. This 50th percentile value was up to 14 g/l more than the mean hemoglobin levels in males of all ages. In females these differences were less apparent. The differences in prevalence of 50th percentile levels between males and females from the age of 10 years were all significant statistically. Of the 1796 people for whom hemoglobin levels and blood groups were determined, 851 weremale and 945 female (Table 2). Thirty-three percent of the subjects had group A (A+ and A ), 12.2% group B (B+ and B ), 51.9% group O (0+ and O ), and 2.8% group AB (AB+ and AB ). Both A+ and B+ were more common in females than in males. Distribution of group O was almost identical in males and females. Group AB (A+) was commoner in males than in females. Of the total samples, 8.4% were Rh negative. There were no consistent associations between blood groups and hemoglobin levels. Figure 1. Distribution of 50th percentile hemoglobin levels by age and sex.

4 Age (y) Table 2. Levels of hemoglobin by blood groups, sex, and percentage of population. Male Hb (g/l) Female Hb (g/l) Overall prevalence Mean Mean rate A A B B O O AB AB Total % No. of subjects The blood groups by nationality are shown in Table 3. Of the 1093 persons whose precise nationality was obtained, 760 (69.5%) were Saudi, 83 (7.6%) Yemeni, 91 (8.3%) Egyptian and 159 (14.5%) were other nationalities. Of the Saudis, 30.2% had blood group A, 9.2% B, 57.1% O, and 3.6% AB. Yemenis were similar to Saudis. Group B was more common in other nationalities than Saudis, Yemenis, and Egyptians (P < 0.05). Nearly 50% of the Egyptians had group A (all A+), and they had the lowest prevalence of O group. Table 3. Blood groups by nationalities living in Abha City. Nationality A+ A B+ B O+ O AB+ AB Total Saudi* No % Yemeni No % Egyptian No % Others No % Total No % * Prevalence of group O in Saudis is statistically higher (P < 0.01) than in the other nationalities in the area. Prevalence of group A in Egyptians is statistically higher (P < 0.01) than in the other nationalities in the area. Discussion For patient care a clear conception about the hemoglobin levels at different heights of a country is essential for every physician. Although there are European and North American standards shown in textbooks, no Arabian standard of reference has been established by taking into consideration the 50th percentile hemoglobin level of the well-born, well-nourished, disease-free, high socioeconomic groups and using proper statistical stringency. This is not an easy task. Until an Arabian standard is available, the various levels so far reported may be used only in the areas from which the data were compiled. For the highlanders, the 50th percentile values, by age and sex, obtained in this study may be accepted as a standard for the people living at about this altitude. Our values are, however, lower than the suggested hemoglobin levels (150 to 220 g/l) at about 8000 feet above sea level.9 Our findings are not much different from Al-Kharj (1000-meter altitude) values (155 g/l for males and 135 g/l for females) but are rather higher than the value reported by El-Hazmi et al.10 In addition to altitude, these differences may also be partly due to nutrients, environmental factors, and methodologies of estimation. Furthermore, the previous studies were not done at the same height from the sea level. This study also confirms that the differences in hemoglobin

5 levels obtained elsewhere, between males and females of different age groups, are also prevalent at the Abha elevation (2500 to 3000 meters above sea level). Our value is higher by approximately 19 g/ L for both males and females than the values at sea level. We may consider that this difference is due to the compensatory effect of hypoxia at Abha. Further, we expected that people of certain blood groups might have some differences in hemoglobin levels, but blood groups showed no consistent association with hemoglobin levels. The prevalence of blood groups in different nationalities is interesting. Although some studies have suggested higher and identical prevalence of A and O groups in Saudis, our study shows that only 30.2% of the Saudis of this area have group A and 57.1% group O. The Egyptians had the highest prevalence of group A (49.5%) and lowest of group O compared to others. The Egyptians and Saudis had lower rates (5.5% and 6.7%, respectively) of Rhnegative blood than the Yemenis (12.0%) and others (11.3%). Furthermore, Egyptians have no Rh-negative A or AB blood groups. This may be a characteristic of Egyptians. These variations may, however, be due to genetic influence. We hope the information obtained in this study will be useful to physicians for patient care at high altitudes and to local administrators who are responsible for procurement of blood from abroad for hospital use. Acknowledgment The authors acknowledge the cooperation of Mr. Hussain Abdur Rahman Faya, Director of the Shamasan Primary Health Care Centre, for allowing us to do this study in the center and thank the staff of the center for their help. Mr. Mike dela Paz and Mr. Rollie Go of the College of Medicine, Abha, deserve thanks for their secretarial assistance. References 1. West JB, ed. Best and Taylor's physiological basis of medical practice. 11th ed. Baltimore: Williams & Wilkins, 1985; Sebai ZA. Health in Saudi Arabia. Riyadh: Tihama Publication, 1985;1: Ghafouri HM, Al-Fares AM, Islam SI, et al. Hematological reference values assessed from birth to adolescence in Saudi subjects in the area of Jeddah. Saudi Med J 1987;8(6): Scott TG. A pilot study of the reference values for commoner haemotological and biochemical parameters in Saudi nationals. J Clin Pathol 1982;35(1): Bacchus R, Garner E, Madkour MM, et al. The hematology reference range for Saudi Arabians. Saudi Med J 1986;8(1): Estimation of haemoglobin by cyanmethaemoglobin method. In: Dacie JV, Lewis SM, eds. Practical haematology. 5th ed. London: Churchill Livingstone, 1975: ABO blood grouping: tile technique. In: Dacie JV, Lewis SM, eds. Practical haematology. 5th ed. London: Churchill Livingstone, 1975;528: The chi-square test. In: Maxwell AE, ed. Analyzing qualitative data. London: Mathuen and Co, 1971: Guyton AC, ed. Textbook of medical physiology. Philadelphia: WB Saunders, 1986; El-Hazmi MAF, Al-Faleh FZ, Al-Mofleh AS, et al. Establishment of normal "reference" for haematological parameters for healthy Saudi Arabs. Trop Geogr Med 1982;34(4):333-9.