Key-words:
ABO - Bani Waleed - blood groups - Libya - rhesus factor
Introduction
The ABO blood groups were discovered by Landsteiner in 1901,[[1]] who divided them into four types, namely A, B, AB, and O blood groups. This division
depends on the presence or absent of certain antigens on red blood cell surface.[[2]] These antigens are inherited from parents and controlled by gene called ABO glycosyltransferase
that located on chromosome 9q34.1.[[3]] Currently, there are 700 antigens that have been reported into 30 blood group systems;
and ABO is the most studied group in the human population.[[4]]
The ABO blood groups have an important role in blood transfusion, where blood donor
group must be identical with blood receive group.[[5]] In addition, the ABO blood groups are important in different medical fields; for
example, there is a relationship between race and ABO blood group distributions, and
it has been important in immunohematology anthropological research. Furthermore, an
association was reported between ABO blood group and many diseases such as cancer,[[6]],[[7]],[[8]] heart diseases,[[9]] and diabetes mellitus.[[10]]
Rhesus (Rh) factor was discovered by both Landsteiner and Weiner.[[11]] There are two types of Rh factors depending on the presence or absence of antigen
D on red cell surface (Rh+ and Rh−).[[12]] Rh antigens are determined by three pairs of allelic genes that located on chromosome
one.[[13]] Rh factor is important during blood transfusion and pregnancy because it causes
hemolytic transfusion reaction or hemolytic disease of a newborn when the Rh− mother has been sensitized to Rh+ blood.[[12]]
The distribution of ABO and Rh blood groups has been reported in different populations
of the world. Many studies have found that blood group O was the most common type
in the USA (46.6%),[[13]] China (34%),[[14]] and Denmark 42.3%.[[15]] The proportion of Rh− reported was different according to the population studied. It was 14.6% in the USA,[[13]] 17.9% in Denmark,[[15]] and 1.0% in China.[[14]] The frequency of Rh− blood group in Al Bayda city in eastern Libyan was reported to be 16%.[[16]]
The present study was aimed to investigate the distribution of ABO and Rh blood groups
in Bani Waleed city population and to compare them with other results from similar
studies within Libya and all over the world.
Subjects and Methods
Study subjects
This is a cross-sectional study carried out between September and December 2018. The
participants were recruited from different clinics including Bani Waleed Hospital,
Bani Waleed University, and Bani Waleed private clinics. The study group included
344 individuals of both genders aged between 15 and 80 years. Clinical characteristics
were obtained for each participant using an Arabic structured questionnaire including
name, gender, age, weight, height, medical history (including diabetes mellitus, heart
diseases, hypertension, and anemia), type of blood group, and address of residence.
The participants were taken from different regions of Bani Waleed to detect if there
is an effect of geographic factor on blood group distribution. Each participant gave
his/her consent about the involvement in this study.
Blood sample collection and blood group determination
Peripheral blood was collected from each participant in the study. Blood groups were
done by slide agglutination method. ABO blood group was determined from each sample
by agglutination using anti-A and anti-B antibodies (Immucor Inc., Norcross, GA, USA).
Rh factor was determined by agglutination using anti-D antibody (Immucor Inc., Norcross,
GA, USA).
Statistical analysis
The proportion of the frequencies and distributions of ABO and Rh blood groups was
analyzed using SPSS version 19.0 (SPSS, Chicago, IL, USA). The Chi-square test was
used to evaluate the differences in ABO and Rh blood groups among the different groups
across all categories and characteristics. P < 0.05 was considered to be statistically significant.
Results
[[Table 1]] shows the distribution of ABO and Rh blood groups in 344 participants according
to gender, age, and geographic location. About 55.8% of the participants were male,
whereas 44.2% were female. The age distribution of the participants was 16.8%, 30.2%,
23.5%, 13.0%, and 6.6% for the age groups of 12–22, 23–33, 34–44, 45–55, and 46–66
years, respectively. About 9.85% were above 66 years old. The mean age of all the
participants was 34.87 years.
Table 1: Gender, age and geographic location of study population
The geographic location of the participated individuals belongs to nine areas of Bani
Waleed city, namely Center of the city (24.1%), Athara area (21.2%), Aloteieen (20.1%),
Industrial area (12.8%), Airport area (2.3%), Tenenai area (7.6%), 51 area (6.1%),
Almardom area (3.8%), and Ashmieg area (2.0%).
Distribution of ABO blood groups
The distribution of ABO blood groups is illustrated in [[Figure 1]]. Type O was the most prevalent (43%), whereas AB type was the least prevalent (7%).
The frequencies of ABO blood groups between genders were analyzed, as illustrated
in [[Table 2]] with no significant difference between them (P = 0.687). The frequencies of ABO blood group among geographic regions of Bani Waleed
are given in [[Table 3]] with no significant difference between them (P = 0.48).
Figure 1: Pie chart shows the distribution of ABO blood group in Libyan population in Bani
Waleed city
Table 2: Gender, age and geographic location of study population
Table 3: Gender distribution of ABO blood group among study subjects
Distribution of rhesus blood group in study population
The frequency of Rh+ in the total sample was 76.2%, whereas Rh− was 23.8% as illustrated in [[Table 4]]. The frequencies of Rh type showed a significant difference (P = 0.017) between the different geographic regions of Bani Waleed using the Chi-square
test [[Table 4]]. On the other hand, no significant difference in the frequencies of Rh type among
genders was found [[Table 5]].
Table 4: Geographic distribution of Rh blood group among study subjects
Table 5: Gender distribution of Rh blood group among study subjects
Distribution of ABO and rhesus blood groups in study population
The frequencies of ABO with Rh blood groups are presented in [[Table 6]]. The O+ type was the most prevalent (33.4%), whereas the AB− was the least prevalent (2.6%).
Table 6: Distribution of ABO and Rh blood groups among study subjects
The frequencies of ABO and Rh types among genders are presented in [[Table 7]]. No significant difference was seen among genders (P = 0.669).
Table 7: Gender distribution of ABO and Rh blood groups among study subjects
Discussion
The prevalence and distribution of blood groups have been reported to be different
in different parts of the world attributed to genetic factors and race differences.[[17]],[[18]] This type of study has an important role in medical practice such as blood transfusion
service and organ transplants.[[19]]
The results of this study had shown that O blood group was the most frequent, followed
by A group, B group, and finally, AB blood group. These results are in good agreement
with the previous local studies in Al Bayda city in eastern Libyan[[16]] and western Libya.[[20]] Moreover, similar results were reported internationally in the USA,[[13]] China,[[14]] Mauritania,[[21]] Sudan,[[22]] and Saudi Arabia.[[23]] These results suggest that O blood type is the most common and AB is the least
common in most world populations. On the other hand, there are other studies that
reported different proportions of ABO blood groups, such as the study in Pakistan
that reported blood Group B was the most common.[[24]] Likewise, A blood group was reported to be the most common in Nepal and Syrian
populations.[[25]],[[26]] Moreover, our study revealed that gender or location has no significant effect
on the frequency of ABO blood groups which are in agreement with a previous study
carried out in Nigeria.[[27]]
As per the results related to Rh blood group, Rh+ was the highest in our study population (76.2%) compared to (23.2%) Rh− group. However, our population with Rh− blood group are higher than those reported internationally in Tanzania (3.2%),[[28]] the USA (14.6%),[[13]] and China 1.0%.[[14]] Local results of Al Bayda city in eastern Libya reported 16% of the study population
with Rh− blood group[[16]] and 8% of Rh− in the Fezzan region.[[29]] Many studies had concluded that Rh+ is a dominant antigen in contrast with Rh−.[[22]],[[30]]
Knowledge of availability and type of blood groups is important for more efficient
delivery of blood bank services. Further, blood group for every individual must be
indicated on national identity cards and driving licenses. It will be of tremendous
use in case of emergencies when urgent transfusion of yet to be cross-matched blood
is required.
Conclusion
The distribution of ABO blood group in Bani Waleed city is in the order of O > A >
B > AB with higher frequencies of Rh− than reported internationally. The data of the current study and other studies of
different geographical regions of Libya will be useful to health planners to face
future health challenges in the region.
Study limitations
Study limitations include small sample size and the inability to study the effect
of race on the distribution of ABO and Rh blood groups in different regions of the
country. This can be suggested as an extension of this important study all over Libya.
