Introduction
All blood was thought to be the same up until the discovery of the ABO blood group more than a century ago, and the catastrophic effects of blood transfusions were not known [1]. The International Society of Blood Transfusion today recognizes 30 human blood group systems, with the ABO and Rhesus (Rh) being the most significant in clinical practice [1,2]. Karl Landsteiner, an immunologist from Austria, discovered the ABO blood group system, the first human blood group system, in 1901. Later, in 1941, Landsteiner and Wiener [3] defined the Rh system, as the second most significant blood group system after the ABO system [4].
The ABO gene (OMIM: 110300) is a gene that encodes for one of the three variant alleles (IA, IB, and IO) of the ABO blood group system and is located on the long arm of chromosome 9 (9q34) [5,6]. The α1,3-GalNAc-transferase and/or α1,3Gal-transferase enzymes that the IA and IB alleles encode catalyze the transfer of various carbohydrates onto the H antigen to generate IA and/or IB (glycosyltransferase) antigens [5,7]. Because the O allele does not produce active glycosyltransferase, neither IA nor IB antigens are produced [5]. In an intra-allelic interaction in a diploid state, the dominant alleles IA and IB are both dominant over the recessive allele IO [8]. The ABO system categorizes all human blood into one of the four groups (phenotypes) A, B, AB, or O with six genotypes, namely, OO (type O), OA (type A), OB (type B), AA (type A), BB (type B), and AB (type AB) [6]. The ABO system is determined by the presence of red blood cell antigens, an antigen A (group A), antigen B (group B), or both anti (type AB) [9].
Due to the prenatal hemolytic syndrome and its significance in subsequent transfusions for Rh-negative people, once they develop Rh antibodies, the Rh system has become the second most significant blood group system [10]. There are currently more than 50 antigens in the Rh blood group system, although D, C, E, c, and e are the main Rh antigens of medical significance [11]. It is controlled by a gene having two alleles (D and d) on the short arm of chromosome 1 [8]. Rh-positive individuals (Rh+)(DD or Dd genotype) are those having the D antigen on their red blood cells, whereas Rh− individuals are those with the D antigen absent from their red blood cells (dd genotype) [12]. Transfusion responses can occur if an Rh− person receives an Rh+ transfusion because the receiver develops anti-D. Contrary to the ABO blood group, Rh antigens never give rise to spontaneous antibodies and large amounts of antibodies must be produced by repeated exposure to trigger a transfusion reaction [13].
The advancement of blood banking services and transfusion medicine has greatly benefited from the identification of the ABO and Rh blood groups. They are helpful in population genetic studies and settling medical and legal disputes like parentage claims [14]. ABO blood group has also been linked in some studies to a number of pathological conditions. For instance, blood group A individuals have been found to have a higher prevalence of stomach cancer and blood group O individuals have been found to be more susceptible to malaria infection than non-O blood group individuals [15,16]. Additionally, a genetic marker for obesity and one of the best predictors of the country’s suicide rate is the ABO blood group system [17].
ABO and Rh blood group systems are the same across the board for all human populations, albeit they vary in terms of frequency and distribution of particular kinds among various racial, ethnic, socioeconomic, and geographic groups [18–20]. ABO and Rh blood group distribution in the British is as follows: type A: 42%; type B: 8%; type O: 47%; type AB: 3%; Rh+: 83%; and Rh−: 17% [21]. In Caucasians in the US, the ABO and Rh distribution is as follows: type A: 41%; type B: 9%; type O: 46%; type AB: 4%; Rh+: 85%; and Rh−: 15% [21]. The distribution in Malaysia is as follows: type A: 24.9%; type B: 30.2%; type O: 38.3%; type AB: 2.8%; Rh+: 98.4; and Rh−: 1.6% [22]. Type A blood makes up 43.8% of the population in Turkey, followed by type B (16.2%), type O (30.8%), type AB (9.2%), Rh+ (86.0%), and Rh− (14.0%) [23]. According to records, blood group O was the most prevalent in Uyo, Nigeria, accounting for 56.10% of all cases. Blood groups A (25.07%), B (16.4%), and AB (2.45%) were next, followed by Rh+ (96.7%) and Rh− (3.30%), respectively [24]. The frequency of the A, B, AB, and O blood groups among students at Ladoke Akintola University in Ogbomosho was 21.30, 22.73, 2.85, and 53.12%, respectively. 93.32% of them were Rh positive, while 6.68% were Rh negative [16]. The results from students at Nasarawa State University showed that blood group O made up 45% of the population, followed by blood groups A (25.5%), B (25%), and AB (3.5%). In Kaduna, a city in the northwest of Nigeria, type A was 21.3%, type B was 24.3%, type AB was 5.2%, and type O was 49.2% [25]. Additionally, Rh+ was 94%, and Rh− was 6%. Additionally, blood group distribution among 160,431 people in Benin, the Niger Delta region of Nigeria, and Benin revealed phenotypes A, B, AB, and O as 23.72%, 20.09%, 2.97%, and 53.22%, respectively [14]. According to a study done in Mogadishu, Somalia, blood groups O and Rh+ predominated with the following blood groups: O group (60.30%), group A (26.50%), group B (11.27%), group AB (1.93%), Rh+ group (96.49%), and Rh− group (3.43%) [26]. Fekadu [27] stated that type O made up 40% of the general Ethiopian population’s ABO blood group distribution, followed by type A (31%), type B (23%), and type AB (6%). The frequencies of O (41.0%), A (24.5%), B (21.3%), and AB (5.2%) as well as 92.06% Rh+ and 7.94% Rh− were reported by Kassahun et al. [28] in the Silte zone of Ethiopia. The proportion of ABO blood groups among the Sidama ethnic group in Ethiopia is type O (51.3%), type A (23.5%), type B (21.9%), and type AB (3.3%) [29]. Similar to this, Teklu and Shiferaw [30] reported that O (43.0%), A (32.0%), B (21.5%), and AB (3.5%) were also prevalent.
The most crucial blood group systems in terms of clinical importance continue to be the genetically determined ABO and Rh systems [31,32]. Calling the patient’s loved ones is the only reliable option when an urgent need for blood donation arises. The most horrifying information to learn is that the majority of these people do not know their blood types, regardless of how long it takes to obtain them. Due to the present emergency, it is crucial for everyone to be aware of their blood type, especially young people, to facilitate blood transfusions. ABO and Rh phenotypic frequencies in various populations have been well-researched. However, the problem is greater in developing countries, especially in resource-limited countries like Africa, as the lack of awareness, and typing antisera as well as the associated costs and logistics were a serious concern [33,34]. Even if some studies on the blood groups have been conducted in Ethiopia, there is no any research done to give full information about the distribution of blood group in the study area, i.e., Southeast Ethiopia. Hence, the present study was carried out to determine the distribution of ABO and D blood groups among second-year medical students of Arsi University (AU), Southeast Ethiopia.
Methods and Materials
The institutional based cross-sectional study design was conducted at AU from June 03 to 20, 2022, among all second-year undergraduate medical students. All medical students at AU at the time of the study were eligible to participate except for severely ill students. AU College of Health Sciences focuses on educating and/or training competent and ethical health professionals for the contribution of paramount in national gross domestic product, particularly the health of the whole community in the growing manufacturing industry, at all levels [35]. The medical curriculum of the School of Medicine at AU takes 6 years during which students stay 3 years in the preclinical and 3 years in clinical practice [35]. An ethical support letter was obtained from AU ethical board. Informed consent was secured and participation was totally voluntary. The confidentiality was kept anonymous. Of the 90 students learning second year undergraduate medical students at AU, 89 (99.89%) agreed to take part. The sociodemographic data was collected by self-administering questionnaire and it comprises age, gender, marital status, residence, income, religion, and ethnicity. Furthermore, the ABO and Rh phenotypes were determined by standard serology methods. A drop of blood was taken from their fingertips using a lancet under aseptic precautions. The blood group was determined by the slide haemagglutination technique. A 2.5% suspension of red blood cells was prepared in normal saline (0.85 g/dl sodium chloride in distilled water) preparation method given below. One drop of blood will be mixed with 1 ml of normal saline in a test tube. This provided the red cell suspension. On one half of the glass slide, one drop of anti-A human polyclonal or murine monoclonal blood grouping serum was placed. On the other half of a glass slide, one drop of Anti-B (yellow color) human polycolonal or murine monoclonal blood grouping serum was placed. Using a Pasteur pipette, one drop of red blood cell suspension was added to each half of the side. On a separate applicator, the serum was well mixed back and forth and observed for agglutination and it was confirmed under a low power objective. Similarly, for Rh D typing, a drop of anti-D serum was placed in a clean labeled tile, mixed with a drop of blood, and watched for agglutination. Results of agglutination were recorded immediately for the ABO blood group and after 2 minutes for Rh.
Data processing, analysis, and interpretation
The questionnaire was pretested on 5% of randomly selected undergraduate paramedical students of AU. Data were checked for completeness daily. To be edited and cleaned, the collected data were double-entered into Epi-data version 3.1 and exported into SPSS version-22 for analysis. Incomplete and inconsistent data were excluded from the analysis. The data were processed by using descriptive analysis and analytical methods, including frequency distribution, cross-tabulation, and summary measures. Descriptive statistics was used to calculate frequencies of the phenotype of the blood ABO and Rh blood groups and results were reported as frequencies and percentages. Allelic frequencies of ABO and Rh blood groups (IA, IB, IO, ID, and Id) were calculated using the HardyWeinberg formula using the following equations [36]. The three alleles of ABO blood groups, i.e., IA, IB, and IO, and their frequencies were represented by p, q, and r, respectively. The frequencies were calculated as follows:
r=√O=Allele IO
p=1 – √B + O=Allele IA
q=1 – √A + O=Allele IB
Therefore, the genotypic frequencies are represented as:
(p + q + r) 2=p2 + 2pq + q2 + 2pr + 2qr + r2=1 and p + q + r=1
where p2 is the genotypic frequency of IAIA, q2 is the genotypic frequency of IBIB, 2pq is the genotypic frequency of IAIB, 2pr is the genotypic frequency of IAIO, 2qr is the genotypic frequency of IBIO and r2 is the genotypic frequency of IOIO as cited in Hanania et al. [37].
The frequencies of the Rh blood group allele, D (dominant allele) and d (recessive allele) were determined as:
q=√Rh−=Allele d
P=1 – q=Allele D
The Rh blood (D) group genotypic frequency was calculated from the allelic frequency under the assumption of Hardy-Weinberg equilibrium as follows:
DD + 2Dd + dd=1
where Genotype DD=p2
Genotype Dd=2pq
Genotype dd=q2
The chi-square (χ2) test (p < 0.05) was used to check whether the observed and expected frequency distributions of the ABO blood groups and Rh factor were in the Hardy-Weinberg equilibrium or not. Odds ratios were calculated and statistical significance was accepted at p < 0.05.
χ2=Σ (Of – Ef)2/Ef
where, Of=Observed frequency;
Ef=Expected frequency
Expected phenotypic frequencies for each blood group were calculated as:
1. A blood group Ef=frequency of (AA + AO) X number of total samples,
2. B blood group Ef=frequency of (BB + BO) X number of total sample,
3. AB blood group, Ef=frequency of AB X number of total samples,
4. O blood group Ef=frequency of OO X number of total samples,
RESULTS
Sociodemographic characteristics
From a total of 90 medical students who received the questionnaire, 89 completed the survey, yielding an overall response rate of 98.89%. The age of the study sample ranged between 20 and 24 years with the mean (SD) of 21.38 (±0.898) years. In the present study, most respondents were female with a frequency of 52 (58.4%), single in marital status with a frequency of 86 (96.6%), living in campus with a frequency of 87 (97.8%), and had a monthly income of ≤1,000 Ethiopian Birr (ETB) with a frequency of 68 (76.4%) (Table 1). Regarding their religion and ethnicity, 42 (47.2%) were Orthodox believers, and 73 (82.0%) were Oromo, respectively.
Table 1.
Sociodemographic characteristics in relation to gender, AU, N=89, June 2022.
| Sociodemographic variables | Male | Female | Total (N=260) | |
|---|---|---|---|---|
| Age | 20–21 years | 12 (20.7) | 46 (79.3) | 58 (100.0) |
| 22–24 years | 25 (80.6) | 6 (19.4) | 31 (100.0) | |
| Current marital status | Single | 36 (41.9) | 50 (58.1) | 86 (100.0) |
| Married | 1 (33.3) | 2 (66.7) | 3 (100.0) | |
| Monthly income | ≤1,000 ETB | 31 (45.6) | 37 (54.4) | 68 (100.0) |
| >1,000 ETB | 6 (28.6) | 15 (71.4) | 21 (100.0) | |
| Residency | Non-dormitory | 0 (0.0) | 2 (100.0) | 2 (100.0) |
| Dormitory | 37 (42.5) | 50 (57.5) | 87 (100.0) | |
| Religion | Orthodox | 12 (28.6) | 30 (71.4) | 42 (100.0) |
| Muslim | 9 (64.3) | 5 (35.7) | 14 (100.0) | |
| Protestant | 16 (51.6) | 15 (48.4) | 31 (100.0) | |
| Othersa | 0 (0.0) | 2 (100.0) | 2 (100.0) | |
| Ethnicity | Oromo | 35 (47.9) | 38 (52.1) | 73 (100.0) |
| Amhara | 0 (0.0) | 5 (100.0) | 5 (100.0) | |
| Sidama | 1 (33.3) | 2 (66.7) | 3 (100.0) | |
| Gurage | 1 (20.0) | 4 (80.0) | 5 (100.0) | |
| Othersb | 0 (0.0) | 3 (100.0) | 3 (100.0) | |
aCatholic, Waqefatta, Faith and Pagan.
bSilte, Harari and Kambata. ETB=Ethiopian Birr. Current exchange rate: $1 USD=52.64 ETB. Statistically significant variables are marked as bold (p ≤ 0.05).
Table 2.
The phenotypic frequency distribution of ABO of blood groups among second-year medical students of AU based on Rh blood group, N=89, June 2022.
| Variables | Blood type | Total N (%) | ||||
|---|---|---|---|---|---|---|
| Type A N (%) | Type B N (%) | Type AB N (%) | Type O N (%) | |||
| Rh factor | Positive | 23 (82.1) | 19 (86.4) | 2 (50.0) | 31 (88.6) | 75 (84.3) |
| Negative | 5 (17.9) | 3 (13.6) | 2 (50.0) | 4 (11.4) | 14 (15.7) | |
| Total N (%) | 28 (31.5) | 22 (24.7) | 4 (4.5) | 35 (39.3) | 89 (100.0) | |
Distribution of ABO and Rh blood groups
According to the present study, in the ABO blood group system, type O was the most prevalent (39.3%), followed by type A (31.5%), type B (24.7%), and type AB was the least frequent (4.5%) in the order O > A > B > AB. Regarding the Rh factor, most of the participants were found to be Rh+ (84.3%) (Table 2).
With respect to the Rh blood group system, among the population studied, blood group O+ was the most common with a frequency of 31 (34.8%), followed by A+ with a frequency of 23 (25.8%), then B+ 19 (21.3%) and AB+ 2 (2.2%), whereas among the Rh negative students, blood group A− was the most frequent 5 (5.6%), blood group O− 4 (4.5%) and B− were 3 (3.4%) each while blood group AB− was 2 (2.2%) (Table 3).
Allelic frequencies of ABO and Rh (D) blood groups
In the present study, the allelic frequencies of the ABO blood group of r (IO), p (IA), and q (IB) were 0.63, 0.20, and 0.16, respectively (IO > IA > IB) while the allelic frequencies of the Rh blood group of D and d were 0.60 and 0.40, respectively. The genotypic frequency of IOIO was the most (0.40) frequent while that of IBIB was the least (0.03) frequent (Table 4).
Observed and expected frequencies of ABO blood group and Rh factor
In the present study, the observed and expected frequencies of individuals having ABO and Rh blood were not significantly different in both blood systems (goodness-of-fit x2 for ABO=1.012, df=3 and for Rh =0.0041, df=1; p < 0.05) (Table 5).
Expected phenotypic frequencies for each blood group were calculated as: A blood group Ef=frequency of (AA + AO) X number of total samples; B blood group Ef=frequency of (BB + BO) X number of total sample; AB blood group, Ef=frequency of AB X number of total samples; O blood group Ef=frequency of OO X number of total samples; Rh+ blood group Ef=frequency of (DD + Dd) X number of total sample; Rh- blood group, Ef=frequency of dd X number of total samples.
Table 3.
Distribution of ABO and Rh blood group systems among second-year medical students of AU based on Rh blood group, N=89, June 2022.
| Blood group | Frequency | Percent |
|---|---|---|
| A+ | 23 | 25.8 |
| B+ | 19 | 21.3 |
| AB+ | 2 | 2.2 |
| O+ | 31 | 34.8 |
| A− | 5 | 5.6 |
| B− | 3 | 3.4 |
| AB− | 2 | 2.2 |
| O− | 4 | 4.5 |
| Total | 89 | 100.0 |
DISCUSSION
Distribution of ABO and Rh blood groups
There are currently 35 systems made up of around 700 human blood group antigens [38]. The ABO and Rh (Rh(D)) systems are the most crucial among them. For a better understanding of human heredity and migratory patterns, researchers are looking into the ABO and Rh blood group antigens. Additionally, the therapeutic and practical value of these blood group systems is significant. They undergo routine screenings in the fields of forensics, paternity testing, legal medicine, and transfusion and transplantation [39]. The ABO blood system is known to be linked to a variety of cancers, including those of the skin [40], pancreatic [41,42], ovarian, gastric [43], and epithelial origin [44,45], as well as other non-communicable disorders such ischemic heart disease [46], and diabetes mellitus [47].
Table 4.
Allelic and genotypic frequencies of ABO and Rh blood groups among second-year medical students of AU, N=89, June 2022.
| Allele | Frequency | Genotype | Frequency | Percentage | Phenotype |
|---|---|---|---|---|---|
| O (r) | 0.63 | IOIO | 0.40 | 40 | O |
| A (p) | 0.20 | IAIA | 0.04 | 4 | A |
| IAIO | 0.25 | 25 | A | ||
| B (q) | 0.16 | IBIB | 0.03 | 3 | B |
| IBIO | 0.21 | 21 | B | ||
| IAIB | 0.07 | 7 | AB | ||
| D | 0.6 | DD | 0.36 | 36 | Rh (D)+ |
| Dd | 0.48 | 48 | Rh (D)+ | ||
| d | 0.4 | dd | 0.16 | 16 | Rh (D)− |
p2 is the genotypic frequency of IAIA, q2 is the genotypic frequency of IBIB, 2pq is the genotypic frequency of IAIB, 2pr is the genotypic frequency of IAIO, 2qr is the genotypic frequency of IBIO and r2 is the genotypic frequency of IOIO. Genotype DD=p2, Genotype Dd=2pq, and Genotype dd=q2.
Table 5.
Comparison between observed and expected frequencies of the ABO blood group and Rh factor among second-year medical students of AU, N=89, June 2022.
| ABO blood group and Rh factor | Observed number (o) | Expected number (e) | Difference (d) | d2/e | χ2 |
|---|---|---|---|---|---|
| Type A | 28 | 25.81 | 2.19 | 0.185 | 1.012 |
| Type B | 22 | 21.36 | 0.64 | 0.019 | |
| Type AB | 4 | 6.23 | −2.23 | 0.798 | |
| Type O | 35 | 35.60 | −0.60 | 0.010 | |
| Rh+ | 75 | 74.76 | 0.24 | 0.0001 | 0.0041 |
| Rh- | 14 | 14.24 | −0.24 | 0.0040 |
Following the initial suggestion 48 years ago, the connection between malaria and the ABO blood group is one of the infectious diseases that is rapidly being acknowledged [48–50]. Due to the close connection between transfusion medicine and organ transplants, the research of blood types is also essential to clinical practice [51]. It is difficult for blood banks to obtain enough blood units, especially for the blood types that are less common [52].
According to the study’s findings, the blood groups were most frequently distributed in the following order: O > A > B > AB, which is consistent with earlier research done in other countries, including Ethiopia. 46% of the USA population displayed Group O, 41% Group A, 9% Group B, and 4% Group AB [53]. In addition, type O is represented by 46% of Western Europeans, type A by 42%, type B by 9%, and type AB by 3% [54]. In the Mexican population, there is a very high prevalence of type O (61.82%), type A (27.43%), type B (8.93), and type AB (1.81%), as well as 95.58% Rh+ [52]. The O > A > B > AB blood group distribution was the norm throughout most of China [55]. In a study on Nepalese medical students, type O (34.87%), type B (30.17%), type A (28.17%), type AB (6.79%), and Rh+ (95.38%) were discovered [56].
Group O makes up 52% of the population in Saudi Arabia, whereas Group A makes up 25%, Group B makes up 19%, and Group AB makes up 4% [57]. In Iran, blood group O is the most prevalent blood type (41.16%) [58]. In Port Harcourt, among students of African origin, among students in the Niger Delta, and among the Yoruba and Hausa ethnic groups, in five zones of Nigeria and Ibadan, respectively, the prevalence of ABO blood groups followed a pattern of prevalence (AB < B < A < O) [59–61]. Like in Egypt, blood group O is the most common [62]. Similar research also revealed that O was the blood group that was most common while AB was the blood group that was least common in Kenya, Uganda, Mauritania, and Ethiopia [63–66]. Blood group O was reported to be the most common disease (41.0%), followed by A (24.5%), B (21.3%), and AB (5.2%) in the Silte zone of Ethiopia [28]. The proportion of ABO blood groups among the Sidama ethnic group in Ethiopia is type O (51.3%), type A (23.5%), type B (21.9%), and type AB (3.3%) [29]. Teklu and Shiferaw [30], in a similar vein, noted the preponderance of O (43.0%), A (32.0%), B (21.5%), and AB (3.5%). Fekadu [27] found that type O made up 40% of the total Ethiopian population, followed by type A (31%), type B (23%), and type AB (6%).
In the current investigation, the relative frequencies of ABO and Rh blood types did not differ from the national trend of O > A > B > AB. Research conducted in India [67] and Pakistan [68] showed blood group B was the most prevalent, followed by blood groups O, A, and AB, in contradiction to the current study. Khan et al. [69] revealed the prevalence pattern of B > A > O > AB in a study conducted in the Bannu region of Pakistan. According to Khattak et al. [20], the percentage frequencies of B (32.40%), O (29.10%), A (27.92%), and AB (10.58%) were found in Pakistan’s Swat district. The majority of investigations in Bangladesh and India have revealed the typical Asian distribution pattern of B > O > A > AB [9]. The most common blood type was B (36.6%), which was followed by O (35.5%), A (21.4%), and AB (7.0%). These blood types showed the same trend of frequency as over the entire Indian subcontinent (B ≥ O > A > AB) [69]. There is regional variation, although; according to some studies, blood group B predominates in Western and Central Africa, whereas blood group O predominates in Eastern and Southern nations [70–72]. In contrast, a different study conducted in Nepal by Pramanik and Pramanik [19] discovered that blood group A is the most prevalent, followed by blood groups O, B, and AB. Similar to this, a few European countries also displayed the A > O > B > AB pattern [9]. The current discovery also differs from earlier findings on the Guinean population, where the population’s frequencies for genes A, B, and O were 14.70, 15.48, and 69.83, respectively [73]. These regional differences may be explained by genetic mapping and the varying origins of diverse ethnic groups and more specifically due to different sample sizes.
The least common blood group in the world’s population, according to all research listed and the current study included, is AB. O is the blood type with the highest prevalence in Britain, whereas AB has the lowest [72]. Blood group AB (3.4%) was the least common, according to data from Saudi Arabia, although blood group O (56.8%) was more common [74]. While most Africans, Americans, Australians, and English people display an O > A > B > AB pattern of ABO phenotypes, most Asians typically have a B > O > A > AB pattern [75].
It is advantageous that blood type O has a higher dispersion than was seen in this study. According to Lemu et al. [76], there is a theory that group “O” phenotypes are more prevalent than non-”O” phenotypes in malaria endemic locations. The indigenous blood type “O” seems to have fared better in terms of surviving acute malaria. On the other side, both Rh-negative and “O” phenotypes may have aided in the spread of malaria in the region as asymptomatic carriers predominated, perhaps as a result of their resistance to the disease, which demonstrated the advantages of the phenotypes. Because studies have indicated that blood type O individuals may not have erythrocytes that are ideal for the creation of rosettes by Plasmodium falciparum, the predominance of the O group may therefore be protective against malaria. Additionally, the higher incidence of “O” blood provides benefits, including the potential for emergency blood transfusions because blood group O is a universal donor (lacking both A and B antigens), making it easily accessible. This might be considered as a good input for blood bank services for efficient blood management and secure blood transfusion procedures [76].
The majority of second-year students at the College of Health Science at AU had Rh positive blood in the current study, which is consistent with the vast majority of research done around the world [77–80]. Rh-negative phenotypic frequency varies considerably amongst populations. The Rh-negative phenotype is less prevalent in Asia and Africa. For instance, statistics indicate that only 1% of people in Madagascar [81] and 6% of people in Nigeria [82] are Rh-negative. Rh negative was also found to be between 0.6% and 8.4% in different parts of India [83]. Less than 1% of people are Rh-negative in China [84,85], Indonesia [86], and Japan [87]. Western countries like the United States [53] and Britain [88], on the other hand, have Rh factor negative of 17 and 15%, respectively, which is closer to the results of the present study. 29% of the population in one area of Saudi Arabia, according to research, is Rh negative [89].
Apart from Saudi Arabia, the High Atlas Range in Morocco has unique communities with Rh-negative rates of roughly 29%, which is the highest reported prevalence of Rh-negative phenotypes [81]. The results of the present study revealed that the frequency of Rh-was very low and the scenario may imply the shortage and difficulty of getting it when required from blood banks and to meet the patient’s needs. Accordingly, Lemu et al. [76] reported that the Rh-blood group is uncommon in many populations, which implies that it is scarcely available in blood banks. As a result, populations, where the Rh- negative blood group is more prevalent, may be approached, and people are encouraged and persuaded to donate blood to increase the availability of this blood group in blood banks.
The prevalence of the Rh factor in the current study is in line with earlier investigations carried out in various regions of Ethiopia. For instance, in Jimma City, 93% of blood donors were Rh+ and 7% were Rh− [30], and Kassahun et al. [28] found that in the Silti zone, 92.06% of donors were Rh+ and 7.94% were Rh−.
Allelic frequencies of ABO and Rh (D) blood groups
The findings of Kassahun et al. [28] in a related study carried out in the Silte zone of Ethiopia were remarkably comparable to those of the present study in terms of the allelic frequencies of O, A, B; D, and d; and Rh factors. According to their research, O (r), A (p) and B (q), D, and d allelic frequencies were 0.65, 0.19, 0.15, 0.72, and 0.28, respectively. Furthermore, they discovered that whereas 7.94% were Rh−, 92.06% were Rh+ [28]. In accordance with the findings of other research carried out in the Oromia National Regional State, the pattern of allelic frequencies in the current study was similarly consistent. For instance, the frequency of IA in the Arsi clan is 0.19, IB 0.16, and IO 0.65, whereas it is 0.21, IB 0.16, and IO 0.63 in the Guji clan and 0.22, IB 0.15, and IO 0.63 in the Borena clan [90]. The genotype IOIO was the most prevalent (41.3%) among the six distinct genotypes. The fact that blood groups A and B (IAIO and IBIO) both possess O alleles in their heterozygous state, in addition to the homozygous IOIO, may be the cause of the IO allele’s preponderance. Allelic frequencies of p (0.154), q (0.249), r (0.591), D (0.676), and d (0.324) have been observed across the entire Indian subcontinent [90], and these allelic frequencies differ from those found in the current study, which had O (r) values of 0.64, A (p), 0.21, B (q), 0.15, D was 0.73, and d values of 0.27. Over allele d, allele D has dominance. Regarding patient safety, it is critical to maintainingmaintaining a sufficient supply of Rh-positive blood. Identification of the Rh blood group system is crucial to preventing the condition known as erythroblastosis fetalis, which frequently develops when an Rh-negative (Rh−) mother is carrying an Rh-positive (Rh+) fetusfetus [91,92]. Additionally, localizedlocalized data on the prevalence of the Rh blood type, among other things, is needed for expanding literature on the relationship between blood groups and the aetiology of cancer [93]. According to the present study’s findings, there was no appreciable discrepancy between the observed and anticipated values for the distribution of ABO blood groups. The observed and expected values for the Rh blood group did not significantly differ.
CONCLUSION
The effectiveness of any national health service depends on having current knowledge of the distribution of blood types in a given area. Blood group O was discovered to have the largest prevalence in the current study’s study population, with a prevalence of 39.3%, followed by blood groups A, B, and AB in that order. Rh positivity was found to be prevalent among students, with Rh negativity being identified only in small numbers. This discovery will help in the organization of healthcare, genetic counseling, and the safe, effective, and well-organized operation of blood transfusion services. The blood types shown on student ID cards from high school or college and driver’s licenseslicenses will come in very handy in cases where an emergency transfusion of blood that hasn’t been cross-matched is needed. It is important to recognize the limitations of the current investigation. Our findings are constrained by a sample size that is too small to provide a reliable assessment of the frequency distribution of blood groups in the research area. Additionally, this survey was carried out with university students in Ethiopia. This could therefore prevent the results from being applied to the entire nation.
ABBREVIATIONS
AU, Arsi University; GDP, Gross domestic product; ETB, Ethiopian Birr; Rh, Rhesus.
Acknowledgments
Authors are grateful to the College of Health Sciences Research and Community Service Office of Arsi University, medical students of Arsi University, data collectors, and supervisors for their support and contribution.
Competing interests
The author declares that there is no conflict of interests regarding the publication of this paper.
Funding
Nil support in financial or other manner.
Availability of data and material
The datasets used and analyzed during the current study are available from the corresponding author upon reasonable request.
Ethics approval and consent to participate
The study received ethical approval from the Research Ethics Committee of Arsi on March 15, 2022 (Serial Number: 0106774; IRB NO:00012098; FWA NO:00018699). Approval to use the records was obtained. Confidentially of the collected data was ensured.
Authors’ contributions
LM and BE had participated in the design of the study, data analyses, and manuscript preparation; and the author could have read and approved the final manuscript.
