High carrier prevalence with poor knowledge of thalassaemia among the university students from indigenous communities in Bangladesh

Thalassemia is an inherited life-threatening but preventable haemoglobin disorder. South Asian countries including Bangladesh are the hotspots of world’s thalassemia belt. Indigenous communities are underprivileged and vulnerable to genetic disorders including thalassaemia. Understanding the perspectives of thalassemia of the future community leaders (indigenous university students) is critical for developing a tailor-made preventive strategy relevant to their communities. In this study, we aimed to assess the level of knowledge and attitudes towards thalassaemia among indigenous university students and determine their thalassemia carrier status.


Conclusions
For the rst time, this study has identi ed knowledge gaps and misperceptions about thalassaemia among university students from indigenous communities with a higher prevalence of thalassaemia. This study serves as a baseline for future interventions (premarital and prenatal screening) targeting future community leaders.

Background
Thalassemia is an inherited haemoglobin disorder, which has no cure, but it is preventable. Once found to be localized in certain parts of the world, thalassemia has become a global public health concern because of increasing international migration [1,2]. An estimated 1-5% of the world population are carriers of thalassaemia [2]. Nearly 90% of these births occur in developing countries [2]. In South Asia, particularly in India, Bangladesh, and Pakistan, thalassaemia has become a silent epidemic with an estimated 45-70 million thalassaemia carriers [3]. In Bangladesh, thalassaemia carriers' prevalence among the general population is estimated to be around 6-12%, which translates into 10-19 million [4,5]. An estimated 60,000-70,000 patients have been suffering from severe forms of thalassaemia (β-thalassaemia major and HbE beta) in the country [3]. Despite a higher prevalence of thalassemia carriers, people are mostly unfamiliar with this disease in Bangladesh [6].
The United Nations has declared that "indigenous peoples are recognized as being among the world's most vulnerable, disadvantaged and marginalized peoples" [7]. Out of approximately 390 million indigenous people globally, Bangladesh is the habitat of around 3 million people of these communities consisting of 1.8% of the total population (over 160 million). The indigenous or tribal people of Bangladesh mostly live in Chittagong hill tracts (CHT, 41%). Among them, Chakma, Marma, and Tripura comprise the largest ethnic minority group consisting of 90% of the indigenous population living in CHT [8,9]. Indigenous communities are underprivileged in terms of education and have less access to healthcare services, mainly because their habitats are located in the country's peripheral remote parts [10]. Nearly 82% of the children aged 5-19 years of age are enrolled in primary or secondary schools [11]. However, around two-thirds of them (65%) fail to complete primary schooling, and another 19% of them are dropped after completion of primary education [11]. The main barriers to keep the tribal students in school are economic, social, remote access from the mainland and armed con icts among different ethnic groups [11,12].
Studies have shown that thalassemia carriers (β-thalassaemia trait and HbE) are highly prevalent (39-47%) among indigenous populations [4]. However, the frequency of different thalassaemia types may vary from one region to another. About 70% of people from Asia, notably the northern regions of Thailand and Cambodia, carry HbE variant. In contrast, the frequency of alpha thalassaemia in the Mediterranean regions, the Middle East to the Indian subcontinent, and the East range 10-25% [13]. Many recent reports have described the higher prevalence of alpha and HbE than β-thalassaemia among tribes/indigenous communities from China, Vietnam, Malaysia, and Thailand [14][15][16][17][18][19]. Given the vulnerable socio-economic conditions, inadequate access to healthcare, poor health awareness, and intra-tribal marriage practice, the higher prevalence of genetic disorders, including thalassemia is expected to accumulate defective genes within the population. Therefore, if this trend is allowed to continue, the tribal population's size will keep reducing gradually, which can further endanger this ethnic minority group.
In addition to the long-term consequences, there is another aspect of health equity for this minority group. Since indigenous people have less access to education, individuals who get an opportunity for higher studies at the university level, are expected to lead their communities. Therefore, understanding the perspective of thalassemia among indigenous university students could be a critical step towards developing a tailored made effective preventive strategy for their communities. In this study, we aimed to assess the level of knowledge and attitudes towards thalassaemia among indigenous university students and determine their thalassemia carrier status.

Study setting
This cross-sectional study was conducted between September 2018 and April 2019 in the students' residential settings (including university-run residential halls and private halls) at the University of Chittagong. Because of its geographic location where most indigenous communities live, and governmental policy promotes higher education, this University reserves seats for indigenous students in every department and institutes of eight faculties under a special quota system [20]. Thus, the University of Chittagong is the most appropriate setting for studying health issues like thalassemia of indigenous communities in Bangladesh.

Sampling
The estimated size of the targeted indigenous students studying at the University of Chittagong is ~ 450 as per the admission o ce [21]. For an accuracy level of 95% with a con dence interval of ± 5.0%, the calculated sample size was 207 [22]. For sampling, eight residential halls of tribal students, including three halls dedicated to female students, were randomly selected.
Moreover, one classroom from the Department of Pali (the language of the Tipiṭ aka) was also included because approximately two-thirds of the students in this department were from indigenous communities. Interviews in residential halls were conducted between 7:00 pm and 10:00 pm on weekdays to maximize the number of participants between May 2018 and October 2018. In contrast, for the academic classroom, the time was 11:00 am and 12:00 pm. Only students who were present physically at each residential hall were enrolled in this study. For all cases, a general announcement was made that a survey on a health-related issue (not mentioning thalassaemia) would take place. Students who agreed to sign the consent form were requested to gather in a large room of residential halls, and their responses were recorded in a printed questionnaire. A team of trained data enumerators, including the principal investigator, supervised the participants during data capture.

Survey instrument
In this study, a previously published questionnaire was used to assess college students' knowledge and attitudes in Bangladesh [6]. In brief, the questionnaire consisted of 22 questions with two major sections prepared in the Bengali language to avoid the language barrier. The demographic section questionnaire was revised to capture the indigenous characteristics of the participants.
Consent and demographic information of the participants were collected at the beginning of the survey. Participants were asked if they had heard of "thalassaemia". Those who answered "yes" were asked to proceed with the survey. The participants' knowledge about thalassaemia was subsequently assessed on 12 items. Of these, nine items were recorded using a 5-point Likert scale (strongly agreed, agreed, don't know, disagreed and strongly disagreed). These nine items were focused on general knowledge of thalassaemia, its carrier, and prevention. A correct response was given a score of one; an incorrect response was scored as -1 and 'don't know' was scored as zero, with higher scores indicating better knowledge. Participants' attitudes toward thalassaemia were assessed by eight items using a 5-point Likert scale. Data were managed and stored using REDCap electronic data capture tool hosted at Biomedical Research Foundation (BRF) for further processing (https://redcap.brfbd.org/).

Carrier screening
For thalassaemia carrier screening, blood samples were collected from interested participants. To maintain ethical guidelines, participants were called privately to know who was interested in carrier screening. Among them, 114 students (49 female and 65 male) participated in the second phase of the study, and written consent was retaken from each participant. All collected samples were then aliquoted into two Vacutainer containing K 3 EDTA (Ethylenediaminetetraacetic acid). Haemoglobin electrophoresis of collected blood samples was carried out using Sebia full automated capillary electrophoresis system prescribed by the manufacturer (SEBIA − 27 rue Léonard de Vinci CP 8010 Lisses − 91008 Evry Cedex FRANCE). In this technique, different haemoglobin species are separated in silica capillaries according to their electrophoretic mobility and electroosmotic ow at a high voltage in an alkaline buffer (pH 9.4).

Statistical analyses
Descriptive and inferential statistical procedures were used to analyze the data. Categorical variables were presented using counts and percentages, and continuous variables were summarized using means and standard deviations. For testing the association between categorical variables, Pearson's chi-square test with continuity correction was used when necessary. The Likert scale measurements were summarized by computing the total scores. Means and standard deviations were calculated for the scores. For continuous variables, normality tests were performed rst, and if needed, nonparametric Kruskal-Wallis oneway ANOVA tests were performed. A p-value smaller than 0.05 was considered signi cant. All data were analyzed using SPSS Statistics for Windows, Version 25.0 (SPSS Inc, Chicago, Illinois).

Respondent characteristics
A total of 251 university students from indigenous communities participated in the study. Students came from 24 out of 25 upazilas (sub-districts) of Chittagong Hill Tracts (consisting of Bandarban, Rangamati, and Khagrachari) except Alikadam of Bandarban (Fig. 1). Most of them (91%) were followers of the Buddhist religion. Two thirds (67%) of the participants were from Arts and Humanities disciplines while the rest were from Social Science (13%), Science (12%), and Business Administration (8%) ( Table 1). Among 251 participants, 123 (49%) reported that their parents were closely related to each other, second cousins, or closer ( Table 2). The rate of consanguineous marriage was signi cantly higher (p < 0.001) among tribal residing in Rangamati (63%), whereas the lowest among tribal from Bandarban (16%). This practice was correlated with ethnicity (p < 0.001) and religious beliefs (p < 0.001). Indigenous students from Chakma were more likely (70%) to marry close relatives (second cousins or closer). More than half (55%) of the participants were unfamiliar with the word "thalassaemia". The proportion of students who had heard about thalassaemia was associated with study disciplines (p = 0.001), different indigenous ethnicity (p = 0.005), and religious belief (p = 0.001). While the majority (~ 74%) of the students from the Science disciplines had heard of thalassaemia, 48% from Business Administration, ~ 43% Arts and Humanities and only ~ 25% students from Social Science faculty had heard of thalassaemia (Table 1).

Knowledge on thalassaemia
Knowledge and attitude were assessed among 112 (44.6%) respondents who declared to have heard about "Thalassemia." The frequently mentioned source of information about thalassemia was the internet (28%), Friends (24%), and Facebook (22%) (Additional le 1). Table 3 reports the distribution of responses of 12 knowledge related questions among indigenous students who had heard about thalassaemia. Overall, knowledge of prevention and treatment of thalassaemia among respondents was poor. Only 20% answered correctly that thalassaemia is a preventable disease if the marriage between carriers is prevented, and more than half of the participants replied that they had no idea about the prevention of the disease. The mean knowledge score was very poor (4.91 ± 2.65). The knowledge level was signi cantly (p = 0.003) higher in females than males. However, knowledge scores were not associated with the disciplines, duration of education, and religious beliefs (Table 4).

Attitudes towards thalassaemia
The attitudes of the indigenous students towards thalassaemia are presented in Additional le 2. The majority (91.1%) of the tribal students would prefer premarital screening to eradicate thalassaemia from society. More than two-thirds (69.6%) of them had positive attitudes to donate blood to thalassemic patients. Three-fourths (75.9%) want to be a friend of thalassemic patients, and most of them (95.5%) showed positive attitudes to raise awareness among their community to prevent the disease.

Discussion
This study's primary objective was to understand the knowledge and perceptions of thalassaemia among university students of the indigenous communities in Bangladesh. Against the backdrop of a higher prevalence of thalassemia carriers, our study has identi ed a signi cant knowledge gap and misconceptions about thalassaemia among the indigenous communities' highly educated segment.
In this study, the nding of a higher prevalence of HbE (38.6%) trait within indigenous communities is consistent with previous studies. It appears that the Tanchangya tribe was more prone to have a higher proportion of HbE trait (57.1%) and the homozygous of E trait, named HbE disease (28.6%). Long-term health consequences of HbE disease are not well understood, and individuals with HbE disease are healthy. However, in our prior study conducted in a specialized thalassemia hospital, we found a few cases (6 out of 11) of patients with E disease requiring regular or occasional blood transfusion [4]. On the other hand, the beta trait prevalence was relatively less common (1.8%) in the present study. However, previous studies documented a relatively higher beta trait prevalence ranging from 3-4.8% [23]. It is important to mention that the severe version (transfusiondependent) of thalassemia resulting from coinheritance beta and HbE trait is highly prevalent (complex heterozygous, E-beta vs homozygous thalassemia major: 77% vs. 15%) in Bangladesh and south-western regions of India (West Bengal). Our previous study has shown that more than 50% of the patients with E-beta thalassemia require regular blood transfusion for survival [4]. It is alarming that without effective interventions, the higher prevalence of thalassemia carriers among indigenous communities in this part of the world may jeopardize their long-term perspective.
Consanguineous marriage practice might be responsible for the higher prevalence of thalassemia carriers within the indigenous communities. Nearly 50% of marriages were consanguineous in the present study, while consanguineous marriage practice is less common in Teknaf, Chittagong region (17.6%) among non-indigenous populations [24]. Notably, around 70% of marriage practice was contagious in the Chakma tribe living in Rangamati. One reason behind the much higher prevalence of consanguineous marriage practice in Rangamati is that it is a district of lakes and hills where free movements are not easy. In this study, 50% of the thalassemia carriers were from Rangamati, indicating the accumulation of defective genes might be linked to consanguineous marriage.
We found most tribal university students (55%) have not heard of the word-'thalassemia.' Best of our knowledge, there is no local dialect synonymous with thalassemia in the indigenous communities. In Bangladesh, nearly 100 million people are internet subscribers [25]. About 39 million of them use social media (Facebook). Young aged students (18-24 years) are the largest user of Facebook [26]. Despite easy access to the internet on university campuses, the proportion of the indigenous students who heard about thalassemia is unexpectedly low (45%).
On the other hand, the overall knowledge scores of the participants who heard about thalassemia were poor irrespective of study disciplines and years of study at the university. For instance, only one-third (~ 35%) of the respondents knew that thalassemia carriers are as healthy as ordinary people. Only one out of ve (20%) tribal students answered correctly that thalassaemia is a preventable disease. In our previous study among college students in the mainland, we found that students with a science background were more familiar with thalassemia since their school curriculum (standard IX and X) dedicated few sentences on thalassemia. Despite having thalassemia related information in the curriculum, the overall knowledge scores were also poor among college students [6]. In general, about 20% of high school students enroll in the science discipline and most of them from urban settings. In this study, we found that most indigenous students had arts and humanities backgrounds (66%), while only 12% had science backgrounds. As the rst step for an effective thalassemia prevention strategy, the inclusion of thalassemia-related information in all disciplines' school curriculum could be highly effective [6]. However, as mentioned earlier, nearly 85% of the tribal students are dropped out before and after the primary level. Thus, unlike students in the general population, the targeting of school level students might not be effective for indigenous communities.
Given the fact that indigenous communities are marginalized and live in the remote part of the country where there is less access to education, information and healthcare facilities Without sensing the communities regarding genetic disorders like thalassemia, any preventive attempt is expected to back re. In this context, educating future community leaders (university students) about the consequence of thalassemia could be a highly effective intervention approach to prevent thalassemia in these communities.
Randomly selected sampling with reasonably large sample size is the strength of this study. However, our study was 'cohortbased' targeting mostly indigenous students of a particular region of Bangladesh (around half the tribal population live here); our ndings may not be generalizable to the entire indigenous population. Figure 1 Spatial distribution of the tribal students participated in the survey of this study (N=251).

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