|Year : 2021 | Volume
| Issue : 1 | Page : 237-242
Screening of β-thalassemia carriers in high school students in Shebin El-Kom, Menoufia Governorate
Seham M Ragb1, Mohammed A Elrahim2, Wafaa M.A. El Fotoh1, Randa A.E. Ibrahim3
1 Department of Pediatrics, Faculty of Medicine, Menoufia University, Menoufia, Egypt
2 Department of Clinical Pathology, Faculty of Medicine, Menoufia University, Menoufia, Egypt
3 Department of Pediatrics, Shebin El-Kom Chest Hospital, Menoufia, Egypt
|Date of Submission||17-Nov-2019|
|Date of Decision||27-Jan-2020|
|Date of Acceptance||01-Feb-2020|
|Date of Web Publication||27-Mar-2021|
Randa A.E. Ibrahim
Department of Pediatrics, Shebin El-Kom Chest Hospital, Menoufia
Source of Support: None, Conflict of Interest: None
To identify the prevalence of β-thalassemia carriers among secondary school children for the prevention program of β-thalassemia and to update carrier rate data in Menoufia Governorate.
β-thalassemia is the most prevalent hereditary disorder and is particularly prevalent among the Mediterranean people, and this geographical association is responsible for its naming.
Patients and methods
This study was conducted on 303 high school students aged 15–18 years from Shebin El-Kom, Menoufia Governorate, Egypt (62% women and 38% men). They were subjected to full history taking and clinical examination. Laboratory investigation included complete blood count, and serum ferritin level. High-performance liquid chromatography was done for samples with normal or high serum ferritin level.
The overall prevalence of anemia among the studied students was 38%. Microcytic type was the most common and represented 57% of anemic students. Men have higher mean hemoglobin values than women in different age groups. Three (1%) students of the total studied students were diagnosed to have the β-thalassemia trait. Moreover, there was a significant difference in ferritin level between β-thalassemia carriers and students diagnosed with iron-deficiency anemia. The mean value of hemoglobin A2 in students with β-thalassemia trait was 5.56 ± 0.42%.
The prevalence of β-thalassemia carriers in high schools was about 1%. A full blood count with microcytosis, together with normal or high serum ferritin level, and hemoglobin A2 more than 3.5% were considered enough for the identification of β-thalassemia carriers in a screening process.
Keywords: anemia, ferritin, hemoglobin A2, screening, β-thalassemia trait
|How to cite this article:|
Ragb SM, Elrahim MA, El Fotoh WM, Ibrahim RA. Screening of β-thalassemia carriers in high school students in Shebin El-Kom, Menoufia Governorate. Menoufia Med J 2021;34:237-42
|How to cite this URL:|
Ragb SM, Elrahim MA, El Fotoh WM, Ibrahim RA. Screening of β-thalassemia carriers in high school students in Shebin El-Kom, Menoufia Governorate. Menoufia Med J [serial online] 2021 [cited 2021 Oct 23];34:237-42. Available from: http://www.mmj.eg.net/text.asp?2021/34/1/237/312052
| Introduction|| |
Thalassemia is recognized as the most prevalent hereditary disorder all over the world with a significant negative impact on public health and the society, especially in endemic areas . The beta form of thalassemia is particularly prevalent among the Mediterranean people, and this geographical association is responsible for its naming. It is estimated that about 1.5% of the world population are thalassemia carriers, with about 60 000 people marked the birth annually; the majority of others are in developing countries . In Egypt, the oldest civilization in the Mediterranean region, thalassemia is the most frequent hemoglobin disorder in the country. The carrier rate of this disease varies between 5.3 and 9%. It was estimated that 1000/1.5 million per year live births suffer from thalassemia disease . β-thalassemia is an autosomal recessive hereditary hemoglobinopathy that affects the production of the β-globin chains of the hemoglobin . They are caused by mutations that nearly affect the β-globin locus and are extremely heterogeneous. Almost every possible defect affecting the gene expression at transcriptional or posttranscriptional level, including translation, has been identified in β-thalassemia. These genetic defects lead to a variable reduction in β-globin output ranging from a minimal deficit (mild β+thalassemia alleles) to complete absence (β-thalassemia) . Thalassemia minor carriers except for mild anemia are clinically asymptomatic. This type of thalassemia is the heterozygous state that only one allele of the β-gene defect on chromosome 11 and the other allele is normal . The hematological features of thalassemia trait are microcytosis, hypochromic, and usually an increase in the percentage of hemoglobin A2 (HbA2). The hemoglobin composition is 92–95% HbA, 3.8% HbA2, and variable amounts of HbF amounting to 0.5–4% . The number in this study was limited due to the high cost of investigation and due to difficulty to take consents from guardian of students. The study was done in Shebin and not in the whole country, and there were similar studies in other centers of Menoufia at the same time, we use systematic randomization sampling. We aimed to identify carriers among secondary school children in Shebin El-Kom, Menoufia Governorate to be taken into consideration for prevention program of β-thalassemia and to update carrier rate data in Menoufia Governorate.
| Patients and methods|| |
The study was approved by the ethics committee of Faculty of Medicine, Menoufia University. This study was conducted on 303 high school students from Shebin El-Kom, Menoufia Governorate, Egypt aged 15–18 years in the first 6 months of 2018. It is a prospective, cross-sectional study. Inclusion criteria included students of high schools located in Shebin El-Kom, of both sexes and in the age range from 15 to 18 years old. Exclusion criteria included students with chronic hemolytic anemia. All studied children were subjected to the following after taking their parents' consent, history taking, focusing on family history about the presence of thalassemia in the family or among the first-degree relatives, history of consanguinity, operations, or drug intake. General examination included evaluation of the general condition with stress on the presence of pallor, mongoloid faces, hepatomegaly and/or splenomegaly, body built, weight, and height.
A measure of 4 ml of blood sample was collected from each student under aseptic condition by clean venipuncture without venous stasis. Blood samples were added to a sterile plain tube and no requirement to wait any length of time between drawing the blood and running the complete blood count. The remaining blood was left to clot at 37°C (for 30 min) and rapidly centrifuged at 4000 rpm for 10 min and then stored at −80°C for the assessment of serum ferritin. Serum ferritin is done for students with microcytic anemia to exclude iron-deficiency anemia (IDA). Iron deficiency was diagnosed based on a ferritin level less than 12 ng/ml. These steps were demonstrated in a stepwise approach for the diagnosis of β-thalassemia trait (βTT) [Figure 1].
|Figure 1: Stepwise approach for investigation and dignosis of β-thalassemia carrier.|
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High-performance liquid chromatography (HPLC) is a sensitive method in the identification of HbA2, HbF, and abnormal Hb. It is the method of choice for thalassemia screening because of its speed and reliability. HPLC was performed via the ARKRAY ADAMS A1c HA-8180T analyzer provided by ARKAY Group (Kyoto, Japan) in thalassemia mode using the protocol provided by the manufacturer. This is a fully automated HPLC analyzer. The analysis time is 3.5 min, the system quantifies HbF, HbA2, HbA, HbA1c, and flags abnormal peaks; common variants HbS and HbC can be detected in separated peaks in the chromatogram. HPLC was done for students with normal or high ferritin levels. HPLC is done for students with a serum ferritin level of more than 12 ng/ml. Students with increased HbA2 levels (HbA2 > 3.5%) are diagnosed as β-thalassemia carriers.
The results were statistically analyzed by statistical analysis of variance, version 20 (SPSS Inc., Chicago, Illinois, USA). Data were analyzed in terms of percentage, mean, SD, Student's t test, and P value. P value is a number between 0 and 1 and is interpreted in the following way. A small P value (typically ≤0.05) indicates strong evidence against the null hypothesis, so you reject the null hypothesis. A large P value (>0.05) indicates weak evidence against the null hypothesis, so you fail to reject the null hypothesis. P values very close to the cutoff (0.05) are considered to be marginal (could go either way) .
| Results|| |
A total of 303 children aged 15–18 years were studied; most of them (46.5%) presented in the age group from 15 to 16 years. Women outnumbered men (62 vs. 38%, respectively). Of these, 21.7% of participants have a positive history of consanguinity [Table 1]. The prevalence of anemia among the total studied students was 38%; microcytic anemia was the most common type (57%) of anemic students [Figure 2]. Hb level showed differences in both sexes; men have a higher mean Hb values than women in different age groups. The highest mean Hb level in men was 13.42 ± 1.48 g/dl in the age group of 17 and 18 years, while the highest mean Hb level in women was 12.32 ± 0.85 g/dl in the age group of 15 and 16 years. There is a significant difference between mean Hb values between men and women in the age groups of 16 and 17 and 17 and 18 years [Table 2]. Three children were β-thalassemia carriers (1%). Hb value and red blood cell count (RBC) indices in both β-thalassemia carriers and IDA were decreased. The mean values of ferritin level were more elevated in β-thalassemia carriers compared with children with IDA [Table 3]. Mean value of HbA2 in students with βTT was 5.56 ± 0.42%.
|Table 1: Demographic data and anthropometric measures of the studied children|
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|Table 2: Hemoglobin level between males and females in different age groups|
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|Table 3: Hematological findings and serum ferritin level in children with β-thalassemia trait and children with iron-deficiency anemia|
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| Discussion|| |
β-thalassemia is a common hematologic disorder in the Mediterranean Basin, parts of North and West Africa, the Middle East, the Indian Subcontinent, the Southern Far East, and Southeast Asia; these areas make up the so-called thalassemia belt. Particularly in Egypt, β-thalassemia has been the most common type of hereditary anemia . Deficiencies in globin-chain synthesis may lead to severe anemia requiring regular blood transfusions and iron chelation therapy starting at an early age. Despite the advances made in treatment over the past decades, many patients with β-thalassemia major, especially those living in developing countries, do not have access to optimal treatment approaches . According to the definition presented by the WHO , based on the prevalence rate of anemia in the region, a prevalence of less than 5% is not considered as a public health problem, but a prevalence from 5 to 19.9, from 20 to 39.9, and more than 40% is considered as minor, average, and major problems of public health, respectively. In our study, 115 (38%) patients had anemia; 50 (43%) had normocytic anemia, and 65 (57%) patients had microcytic anemia, and 188 (62%) children had normal values. The reason for the high percentage of microcytic hypochromic anemia might be due to iron deficiency in adolescents because of rapid growth, hormonal changes, and starting of menstrual period in girls. Also, Tesfaye et al. studied 408 school adolescents in Southwest Ethiopia; the overall prevalence of anemia was 15.2% (62/408), of the adolescents with anemia, more than half of them had microcytic hypochromic anemia (53%), followed by normocytic normochromic anemia (40%) and macrocytic normochromic anemia (7%). Our study showed that men have higher mean Hb values than women in different age groups and the mean of hemoglobin concentration of the β-thalassemia carrier (11.9 ± 1.05 g/dl) was lower than that of all enrolled participants (12.4 ± 1.11 g/dl). This is in accordance with Bhukhanvala et al. , who observed that the mean hemoglobin concentration was lower in βTT children (11.0 ± 1.4 g/dl).
Red cell indices should be sufficient to raise suspicion of a β-thalassemia carrier and therefore to perform further evaluation . A combination of mean corpuscular volume (MCV), reticulocyte distribution width (RDW), and the RBCs is more effective for identifying βTT and differentiating it from other non-thalassemic microcytosis . In this study, MCV values ranged from 69 to 71 fl with a mean value of 70 ± 1.05 fl. Mean values of RBCs, mean corpuscular hemoglobin (MCH), and RDW were 5.31 ± 0.39 × 106/mm3, 22.36 ± 0.42 pg, and 13.8 ± 0.95%, respectively, in β-thalassemia carriers. In agreement with us Grow et al. reported that in case of β-thalassemia minor, MCV will be less than 80 fl, MCH is less than 27 pg, and the Hb level in men is between 11.5 and 15.3 g/dl and in women is between 9.4 and 14.0 g/dl. Also Rathnayake  stated that the screening for β-thalassemia relies on MCV and MCH. Those with an MCV of more than 80 fl and an MCH of more than 27 pg are considered noncarriers and others with MCV values of less than 80 fl and MCH values of less than 27 pg would be referred for HPLC to confirm thalassemia carrier state. Ferritin is a complex of iron and the binding protein apoferritin. Ferritin reflects true iron stores and is not susceptible to short-term variations that occur with serum iron levels and total iron-binding capacity. Ferritin is an acute-phase reactant and can be elevated with liver disease, malignancy, and chronic renal disease. IDA is likely if the ferritin level is less than 15 ng/ml (15 μg/l) in an otherwise healthy person, or less than 50 ng/ml (50 μg/l) in a person with an underlying source of chronic inflammation. IDA can usually be excluded when the ferritin level is greater than 100 ng/ml (100 μg/l) . Normal ferritin levels range from 12 to 300 ng/ml in men and from 12 to 150 ng/ml in women . In our study the ferritin level in βTT children range from 78.80 to 309 ng/ml with a mean value of 166.26 ± 24.65 ng/ml. Supporting our results, Chakrabarti et al. stated that serum ferritin assay reflects the body iron status and it remains within the normal range in case of βTT. Moreover, Akther concluded that microcytosis accompanied by a high RBC count, normal RDW, and an elevated level of HbA2 is suggestive of βTT. Microcytosis accompanied by a low ferritin value suggests iron deficiency.
In our study, the mean of hemoglobin F for βTT was 1.13 ± 0.21% and its values range from 0.9 to 1.3%. As regards HbA2, it ranges from 5.1 to 5.9% with a mean value of 5.56 ± 0.42%. For β-thalassemia screening, people with increased HbA2 levels (HbA2 >3.5%) are diagnosed with the βTT . Marengo-Rowe stated that an elevated HbA2 with an average value of about 5%, along with microcytic hypochromic indices, is characteristic of βTT. In this study, there were three children (about 1% of total students) who were diagnosed as β-thalassemia carriers. They represent about 4.6% of microcytic samples. Much higher prevalence of β-thalassemia carriers was reported by El Beshlawy et al. , who studied 1000 school-aged randomly selected children from Egypt. About 9% of them were diagnosed as β-thalassemia carriers with high levels of HbA2 more than 3.6% and normal levels of iron parameters. Hesham also published a carrier rate of 8.5% among 614 secondary school students in Diarb Negm, Sharkia Governorate. A study by Koyunuc and Aslan screened about 14 200 couples before marriage for βTT in Denzili, Turkey, in which carriers of β-thalassemia were identified in 2.2% of screened samples. In India, Madan et al. showed that the carrier frequency of β-thalassemia varies from 3.0 to 20.0%. In another Indian study, Tiwari et al. studied the prevalence of βTT in microcytic blood donor samples and the prevalence was 36% in all microcytic donor samples (18 from 50 microcytic samples).
From the above, the carrier rate in our study is lower than the rate observed in most studies. We think that the reason is the low distribution of the disease in this area (Shebin El-Kom, Menoufia Governorate), where no previous records about carrier rates were reported. Overall, we found that early screening for β-thalassemia is very important and efforts should be exerted for the establishment of wide nation screening programs in Egypt. Thalassemia carrier screening contributes to reducing the incidence of β-thalassemia, and carrier screening is an essential intervention in all these prevention programs to save Egypt's economy.
| Conclusion|| |
The prevalence of β-thalassemia carriers among high school children was about 1%. A full blood count with microcytosis, together with normal or high serum ferritin levels, and HbA2 more than 3.5% is considered enough for the identification of β-thalassemia carriers in a screening process.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3]