Anaemia Prevalence, Severity and Associated Risk Factors Among Indigenous Temiar Orang Asli Community in Kelantan, Peninsular Malaysia

Anaemia continues to be a major public health challenge in developing countries. An important and often unreported group at risk for anaemia is indigenous communities. This study aimed to assess the prevalence of anaemia and to identify its determinants in the indigenous Temiar Orang Asli community in Peninsular Malaysia. A community-based cross-sectional study was conducted in 2019. Six hundred and forty participants aged one and older were enrolled and personal characteristic data were collected. Anaemia status was determined using haemoglobin level (Hb) according to the World Health Organization (WHO) Hb cut-off. The overall anaemia prevalence was 44.7% (286/640) and the prevalence rates of mild, moderate and severe anaemia were 42.7%, 50.7% and 6.6%, respectively. Anaemia-specic prevalence varied signi�cantly by age groups (P<0.001) and was highest in the 6–17 group for mild anaemia (39.3%, 95% CI: 30.6–48.6), followed by ≤ 5 group for both moderate anaemia (43.4%; 95%CI: 35.2–51.9) and severe anaemia (42.1%; 95%CI: 20.3–66.5). In the multivariate logistic regression, anaemia was associated in age groups of ≤ 5 (adjusted odds ratio [aOR] 5.6 [95%CI: 3.3–9.4], P<0.001) and 6–17 (aOR 2.1 [95%CI: 1.4–3.2], P<0.001) as well in those living in Lambok (aOR 2.7 [95%CI: 1.3– 5.5], P = 0.006). This study has highlighted the high prevalence of anaemia among indigenous Orang Asli in Peninsular Malaysia and revealed that younger children were positively associated with childhood anaemia. Effective interventions and special attention for this indigenous population need to be implemented to reduce the risk of anaemia.


Background
Anaemia has been recognised as one of the serious global public health problems as its affects more than two billion people, which corresponds to 24.8% of the world's population 1 .Anaemia is de ned as the amount of red blood cells or the concentration of haemoglobin (Hb) inside the blood cells is lower than that required by the human body 2,3 .Haemoglobin is needed to carry oxygen and the blood's ability to carry oxygen to the body's tissues will be reduced if someone has too few or abnormal amounts of red blood cells or not enough Hb.This may result in general symptoms such as frequent vagueness, fatigue, shortness of breath and poor concentration 4 .
Anaemia has multiple precipitating factors and may result from a multifactorial de ciency of micronutrients (e.g.iron, folic acid, vitamin A and B12), infectious diseases (e.g.malaria and helminth) and inherited disorders (e.g.sickle cell disease and thalassemia) 5,6 .Almost all of the age population groups are affected by anaemia, ranging from newborn to older age.However, women of childbearing age are at higher risk of developing a condition due to blood loss from menstruation 7 .Infants between 1 and 2 years of age also are at risk for anemia, if they did not get enough iron in their diets 8 .According to the world health organization (WHO), 42% of children less than 5 years old of age and 40% of pregnant women worldwide are estimated to be anaemic 9 .Furthermore, people that live in the less developed areas of the country and among hard-to-reach populations are more susceptible to anaemia because of poor quality diet, social-emotional and exposure to parasitic infections 10 .
An important and often unreported group at risk of anaemia is the indigenous population 11 .In most cases, anaemia is a mild problem among indigenous people living in developed countries, and it has reached a serious level in the poorer regions of the world 11 .As minorities, indigenous communities often experience signi cant and persistent differences in the social determinants of health, including access to healthcare services, education, employment, housing and food security 12 .This is related to the aetiology of anaemia, which includes insu cient diet and poor living conditions as well as an association with infectious diseases including malaria and intestinal parasites 5,6 .
In Malaysia, the indigenous minority people known as Orang Asli represent 0.6% of the total population of Malaysians 13 .The Orang Asli in Peninsular Malaysia are divided into three main tribes (i.e.Negrito, Senoi and Proto-Malay), with the Senoi tribe being the largest ethnic group constituting 55% of the total Orang Asli population with a large majority from the Temiar sub-tribe (Malaysia Department of Orang Asli).Approximately 37% of 869 Orang Asli villages throughout the country are still located in remote and forested areas 14 .Poverty and remote settlements have previously reported contributing many health problems related to malnourishment and high incidence of infectious diseases in these communities 15,16,17,18,19,20,21,22 .Although several studies have been conducted to assess the prevalence of anaemia in Malaysia, there is a dearth of information on anaemia status among the Orang Asli population in the country.In response, this study aimed to determine the prevalence and associated risk factors of anaemia among indigenous Orang Asli communities in Peninsular Malaysia.Results from this study would be useful for informing national prevention strategies and could be used by several already existing national agencies dedicated to improving morbidity and mortality among indigenous peoples.

Ethics statement
This study was conducted in accordance with the Declaration of Helsinki and was approved by the Medical Ethics Committee of the National University of Malaysia (UKM) (Reference No. UKM PPI/111/8/JEP-2019-148) and the Department of Orang Asli Development, Ministry of Rural and Regional Development Malaysia.Participants were sensitized to the study objectives and procedures by the local health district personnel for the study participation.

Study area and population
The study was conducted in Pos Kuala Betis (latitude 4 o 53'22''N; longitude 101 o 45'30''E), a clustered rural resettlement (RPS) of ve villages (i.e.Angkek, Betak, Galas, Lambok and Podek) located at the Gua Musang district, Kelantan State, Peninsular Malaysia (Fig. 1).The Temiar sub-tribe of the Senoi was known to be the main indigenous Orang Asli in these villages.Located approximately 40km from Gua Musang town, the typical climate of the study area is tropical monsoon with temperature ranged between 20°C to 32°C and average annual rainfall between 2,000 mm to 4,000 mm.While the main economic activity was centred on agriculture such as palm oil plantation, the livelihood of the villagers mainly depended on rubber-tapping, labourers, farmers and gathering and selling forest products 23 .Previous studies have shown that this locality experienced high intestinal parasitic infections 24,25 as well as recurrent malaria outbreaks, which possibly related to autochthonous outbreaks of vivax malaria in the neighbouring state 20 .

Study design and sampling techniques
A community-based cross-sectional survey was carried out between June and July 2019 23 .All indigenous Temiar Orang Asli of both sexes, residing in the study villages and aged one and older were invited to take part in the study.Participants were explained about the study protocol and informed consent was documented.For the illiterate participant, informed consent was obtained in the presence of an independent literate witness.For children and adolescents below 18 years old, informed consent was obtained from parents or legal guardians.District healthcare providers and community leaders were purposely involved in the study to facilitate participation and cooperation among the community 23 .
Participants were divided into four groups following age strati cation practices in Malaysia namely infants and children (≤5 years), school-going children and adolescents (6-17 years), young adults (18-40 years) and older adults (>40 years).

Data collection
Gender, age and location were recorded for each participant.A blood sample was obtained by nger prick and Hb level was measured with the HemoCue Hb 201 Analyzer (HemoCue, Sweden), and was expressed as g/L.Anaemia was classi ed as mild, moderate or severe based on the concentrations of Hb in the blood.According to WHO criteria 26 , for children aged 6-59 months and pregnant women, anaemia is de ned at Hb <110 g/L (100-109, 70-99, and <70 g/L correspond to mild, moderate and severe anemia, respectively).For children aged 5-11 years old, anemia is de ned as Hb <115 g/L, in which 110-114, 80-109, and <80 g/L correspond to mild, moderate and severe anemia, respectively.While for children 12-14 years old and non-pregnant women (15 years of age and above) anaemia is de ned as Hb <120 g/L (110-119, 80-109, <80 g/L refer to mild, moderate and severe anaemia, respectively).Lastly, in men (15 years of age and above), anaemia is de ned as Hb <130 g/L, in which 110-12.9, 80-109, <80 g/L correlate to mild, moderate and severe anaemia, reciprocally 26 .

Statistical analysis
All survey data were double entered into Microsoft Excel spreadsheets and cross-checked for errors.Data were processed and analysed using STATA/SE 13.1 statistical software package (StataCorp, USA).Differences in proportions were tested using the Chi-squared test or Fisher's exact test.95% con dence intervals (95% CI) were estimated to provide uncertainty surrounding the point estimates.Logistic regression was used to identify factors associated with anaemia in the community.Gender, age group and village were considered as explanatory variables in the univariate analyses.All variables with a Pvalue of <0.10 from the likelihood ratio test in the univariate analyses were included in the multivariate logistic regression model and stepwise backward elimination was used to identify the main risk factors for anaemia 27 .A P<0.05 was considered statistically signi cant.

Characteristic of the participants
A total of 640 individuals from Pos Kuala Betis (representing 68% of the combined population in the ve villages) participated in this study (Table 1 15,16,29,30 .However, these ndings were contrary to a recent study conducted among the present-day hunter-gatherer of indigenous Negritos Orang Asli an overall anaemia prevalence of 68.4% 22 .The that a high prevalence of anaemia among indigenous populations is widely distributed in Malaysia, suggests that common disparities in health among these diverse groups of are attributing to a higher of anaemia. The nding of this study demonstrated that the prevalence of anaemia was signi cantly higher in children and adolescents ≤17 years, 55.9%) compared to (i.e.≥18 years, 33.3%).This is consistent with the ndings of earlier local studies conducted among Orang Asli in Peninsular Malaysia 16,18 .The variation in prevalence and severity of anaemia tends to be convex with age, increasing in childhood and decreasing in adulthood 30 .This may be because the child's exposure to be anaemic rises as he or she gets older.It is common for children to be more active, and eager to learn new things in their surroundings.However, many of them are still unaware of personal and appropriate hygiene practices and the consequence of exposing themselves to infectious organisms due to their early age.Meanwhile, as in agreement with a previous study by Muslim et al 22 , gender strati cation in this study showed no difference between the prevalence of anaemia between the females and males although it is well acknowledged that females tend to be more anaemic as a result of physiological differences 7,31 .
The present study also revealed that anaemia-speci c prevalence of both moderate and severe anemia was highest in children age less than 5 years old with 43.4% and 42%, respectively.Besides, the odds of anaemia were almost six times higher for the ≤ 5 group when compared to those in 18-40 group in the population.These scenarios are in agreement with previous reports 18,22,32 , whereby the younger children from the indigenous population in Malaysia had a higher prevalence of anaemia compared to older children.In the Orang Asli community, older children are usually enrolled in boarding schools provided by the government.It is postulated that a feeding intervention that had been implemented in the boarding school could re ect the lower prevalence of anaemia among older children.Previous studies have shown that the contributing factors of anaemia among children of the indigenous population in Malaysia are largely due to poor dietary intake of iron, recurrent infections and low socioeconomic status 32,33 .Furthermore, preschoolers depend on their caregivers to provide food for most part of the day.Because of that, a caregiver with a lack of knowledge of proper nutrition, low socioeconomic status, unemployed and low level of education attributed to childhood malnutrition.This issue deserves attention because chronic anaemia during childhood has been shown associated with retardation in physical development and cognition, while severe anaemia is responsible for more than half of the deaths in children under 5 years of age 34 .
Other than micronutrient de ciencies, anaemia can also occur when excessive amounts of blood are lost due to gastrointestinal infections associated with diarrhoea.Thus, infections related to hygiene, sanitation, safe water and water management are signi cant contributors to anaemia 35 .Recurrent infections especially due to soil-transmitted helminth (STH) often signi associated with anaemia among Orang Asli communities 15,16,17,18,19,21,22 .Infections with heavy loads of the Trichuris trichiura were reported having the most cant correlation with anaemia as well as a strong predictor of iron de ciency anaemia and growth stunting in the Orang Asli population 15,21,22 .In the high-risk groups of anaemia, for example, children aged under 5 years; multifactorial that coexist to affect the risk of anaemia due to the combined effect of growth and physiological state in this vulnerable group 36 .As a vicious cycle of malnutrition and infection, children with the weak immune systems due to malnutrition are more likely to have a higher risk of developing severe anemia causing increase susceptibility to infection while their childhood environment has high exposure to infections which may also cause malnutrition 37 .
Local variation in anaemia prevalence was also observed among communities on the same clustered rural settlement.The present study showed that anaemia prevalence in the ve villages in Pos Kuala Betis ranged from 30-52%.Further ndings showed that living in Lambok was found to be signi cantly associated with anaemia compared to other villages.Although these villages belong to the same cluster resettlement, they differ greatly in their location and access to the general population.For an instant, the Lambok community lives the furthest in a forested area with impoverished agriculture and incomplete basic infrastructure amenities.In contrast, the Betak community is in a fertile plain with easy access to a nearby town.Thus, micronutrient de ciencies (i.e.anaemia) in the Lambok community are likely the result of inadequate diets and parasitic infections from food and water contamination.The heterogeneity in anaemia prevalence within indigenous communities due to the different in location and access to food has also been reported in other setting 38 .Like many other indigenous communities globally 11 , Orang Asli communities in Malaysia are often located in deeply remote areas with a lack of basic amenities such as piped water supply, electricity, toilet facility, garbage disposal service as well as limited access to government health programs 17,39 .Tackling these issues could ultimately lead to a greater reduction of intestinal parasitic transmission, subsequently lower the prevalence of anemia in Orang Asli communities.
A number of caveats should be considered in this study.First, although the cross-sectional nature of the research design was e cient and cost-effective, it has an inherent selection bias and does not allow causality to be established.Second, the lack of data on micronutrient de ciencies, infectious diseases and genetic predispositions is important for understanding the causes of anaemia in the study population.Hence their confounding in uence could not be ascertained.Third, the use of capillary blood instead of venous samples can also constitute a source of bias.At the moment when the surveyor pricks the skin and collects blood drops, the Hb can be diluted with extracellular uid through manipulation of the subject's nger 40 .Nonetheless, this technique offers many practical advantages and does not affect the quality of diagnosis at the population level 41 .Fourth, the nature of the logistic regression model developed with a limited number of variables are also the additional limitation of this study.

Conclusion
In conclusion, anaemia constitutes a major health problem particularly among the school-age children of the indigenous Temiar Orang Asli community in Peninsular Malaysia.The magnitude anemia in this study carries public health importance, particularly in planning programs for community health and could help develop intervention strategies and target high-risk subpopulations in this vulnerable population group.This speaks to the aetiology of anaemia, which includes inadequate diet and poor living conditions as well as an association with malaria and intestinal parasites.Further research needs to be done to ascertain the exact cause of anaemia in this community.

Declarations
Figures

Figure 1 Map
Figure 1

Table 1
).The surveillance coverage varied among villages from 50 to 90%, being mostly females (58%; 95% CI: 54.1-61.8)and the age of participants ranged between 1 to 88 years old (mean [standard deviation; SD] age of 22.6 [17.8] years).A slight majority of the participants were school-age children and adolescents in the 6-17 age group (34.1%; 95% CI: 30.4-37.9).Demographic characteristic and anemia status of indigenous Temiar Orang Asli population in ve villages of Pos Kuala Betis, Kelantan, Malaysia Of all participants, the overall prevalence of anaemia was 44.7% (95% CI: 40.8-48.6)and not signi cantly different between villages (P = 0.092) (Table 1).The anaemia-speci c prevalence among participants in Pos Kuala Betis is shown in Table 2.The prevalence of mild, moderate and severe anaemia was 42.7% (95% CI: 36.9-48.6),50.7% (95% CI: 44.7-56.6)and 6.6% (95% CI: 4.1-10.2),respectively.Although the prevalence of anaemia was highest among females (57%; 95% CI: 51.0-62.8),no signi cant difference was observed between the three anaemia severity classi cations (P = 0.691).Nevertheless, the prevalence of anaemia varied signi cantly by age groups (P < 0.001) and was highest in the 6-17 age group for mild aneamia (39.3%, 95% CI: 30.6-48.6), followed by ≤ 5 age group for both moderate anaemia (43.4%; 95%CI: 35.2-51.9)and severe anaemia (42.1%; 95%CI: 20.3-66.5).Temiar Orang Asli was within similar ranges reported in other indigenous tribes in Malaysia i.e. the Senoi and Semai in Peninsular Malaysia, and Penan Iban in Malaysian Borneo 28Comparison between the ve villages b Census from the Demographic Surveillance System of District Health O ce of Gua Musang c WHO classi cation of anaemia on the basis of blood haemoglobin level (WHO 2011)Anaemia-speci c prevalenceComprehensive results for all signi cant co-variables associated with anaemia in univariate analysis (P < 0.05) are provided in Table3, and these variables were further used to build multivariate models withDiscussionIn this study, the current status and risk factors of anaemia among the indigenous Temiar Orang Asli in Peninsular Malaysia were determined.Overall, this study has shown a high anaemia prevalence of 44.7% particularly among children and adolescent, and considered a severe level (i.e.>40%) based on the ranges of anaemia among indigenous populations globally11.Although this gure was two folds higher than the anaemia incidence among the general Malaysian population i.e. 24.2%28, the prevalence of anaemia among the