Prevalence and Risk Factors of Iron Deficiency Anaemia in Children admitted in a Tertiary Care Hospital of Bangladesh

Address for correspondence: Dr. Md. Mahbubul Hoque FCPS, Professor of Neonatology, Bangladesh Institute of Child Health, Dhaka Shishu Hospital, E-mail: dr.hoquamm@yahoo.com, mahbubulhoque2013@gmail.com Tel No; +88


Introduction
A naemia is a common problem in childhood especially aff ec ng children aged 6-24 months.It has been es mated that among children below four years of age, 12% are anaemic in developed countries while 51% in the developing world 1 .In Bangladesh, 64% of children aged 6-23 months and 42% of children aged 24-59 months are anemic 2 .Anaemia is primarily associated with nutri onal defi ciencies such as iron defi ciency, the main factor responsible for microcy c anaemia; while folate or vitamin B 12 defi ciencies are responsible for macrocy c anemia 3,4 .
Ae ology of anaemia in tropical countries is mul factorial.It has been noted that infants breas ed for more than 6 months without receiving iron for fi ed complementary foods or iron supplementa on are at risk of developing iron defi ciency anaemia (IDA) 5,6 .Other risk factors for anaemia include low birth weight, unusual perinatal haemorrhage, prolonged consump on of large amounts of cow's milk, and intes nal infec on, such as hookworms and diarrhoea 7 .
Iron defi ciency is the most profound form of nutri onal defi ciency in developing and developed countries 3,8 .According to the World Health Organiza on (WHO), IDA aff ects 43% of the world's children, 1 while UNICEF reported that around two billion people globally suff er from anaemia with the highest propor on suff ering from IDA, especially in developing countries, where 40-50% of children under age 5 are iron defi cient 9 .
Anaemia impairs normal development in children and it cons tutes a major public health problem in young children in the developing world with wide social & economic implica ons.Even mild anaemia can decrease physical exercise tolerance and intellectual performance of children.Anaemia may also cause growth retarda on in children 3 .Furthermore, iron defi ciency, leading to anaemia, is found to be associated with abnormali es in cell-mediated immunity and the ability of neutrophils to kill several types of bacteria 10 , along with poorer psychomotor development and behaviour changes of young children 11,12 .Iron is necessary for maintaining normal structure and func on of virtually all mammalian cells and is also involved in the immune and non-immune host defence. 13Data suggests that infants with IDA are at higher risk for long-las ng developmental disturbance, when compared to their healthy peers 14,15 .
Thus it has been suggested that infants and toddlers should be screened for anaemia, especially IDA.This study was to assess the contribu on of several presumed risk factors for the occurrence of iron defi ciency anaemia in six months to thirty six months old hospitalized children who were admi ed due to other acute illnesses.

Materials and Methods
Study site: This cross-sec onal study was conducted in Dhaka Shishu (Children's) Hospital (DSH) over a period of three months from 1 st June 2010 to 30 th August 2010.DSH is the largest ter ary care paediatric teaching hospital in Bangladesh that provides care to the children from all over the country.It has a large Out-pa ent Department (OPD) and an In-pa ent Department with 550 beds that includes diff erent subspecial es.

Study Popula on:
Children aged six months to thirty six months, who were admi ed during this period due to any acute illness like acute respiratory tract infec on, acute gastroenteri s, etc., and whose parent or guardian provided informed consent, were eligible for enrolment.Children who have been suff ering from chronic illness such as haematological and renal disorders, severe malnutri on, persistant diarrhoea etc. were excluded from the study, also children who received blood transfusion before admission due to any cause were excluded.
At enrolment a detailed case history was taken and thorough physical examina on was performed and recorded on standard case record forms.Historical informa on included socioeconomic status (parents' educa on and monthly income), birth history (prematurity, low birth weight) and detailed feeding prac ce since birth was recorded.Based on monthly income, socioeconomic status was defi ned as: low income Bangladesh Taka (Tk.) <5,000, lower-middle Tk. 5,000 to 20,000, and upper class Tk. >20,000.
Laboratory inves ga ons: Complete blood count (CBC) including peripheral blood fi lm was done in all cases on enrolment.A blood sample (2 ml) was collected by venepuncture into an ethylenediaminetetraace c acid (EDTA) coated tube.The coulter counter machine was used for haemoglobin (Hb) measurement, erythrocyte count and mean red cell volume.The mean corpuscular volume (MCV) was derived from these values.
In addi on, if peripheral blood fi lm showed microcy c hypochromic RBC, further inves ga ons for serum ferri n (2 ml blood, collected in a plain test tube for the measurement of serum ferri n by immunoenzymometric examina on), stool rou ne and microscopic examina on, haemoglobin electrophoresis and C-reac ve protein (CRP) were performed.Iron defi ciency anaemia was defi ned when concentra on of serum ferri n were less than 12 microgram/L 18 .Serum Iron and TIBC could not be performed due to fi nancial reason.
Ethical issues: Ethical permission was taken from Ethical Review Commi ee of Bangladesh Ins tute of Child Health.Informed wri en consent was obtained from parents or primary caregivers of the children before enrolment.Results of laboratory tests were communicated to the parents.Advice for preven on of anaemia was given and correc on was done when needed.
Sta s cal analysis: The data were entered and analyzed using SPSS version 12.0 for Windows (SPSS Inc, Chicago, IL, USA) so ware.Standard test for signifi cance using Chi-square (χ2) test and mul variate predictor analysis were performed.A p-value of <0.05 was considered as sta s cally signifi cant.

Sample size:
Using the anaemia prevalence of 68% in a similar age group as reported in a previous survey, we es mated a sample size of 335 children based upon the following formula: where N = sample size, t = confi dence level of 95% (= 1.96), p = es mated prevalence of the variable, and m = margin of error at 5-10% (5% = 0.05).
Among 205 male children, 123 (60%) were anaemic and among 126 female children, 78 (62%) were anaemic; the diff erence between gender was not sta s cally signifi cant.Anaemia had direct rela onship with socioeconomic status, lower the socioeconomic status, higher the rate of anaemia (Table 1).
Premature birth and low birth weight were found to be signifi cantly associated with occurrence of anaemia (Table 2).
Poor feeding prac ces like colostrum rejec on, non-exclusive breas eeding, early/late weaning and inappropriate weaning diet are important risk factors for childhood anaemia (Table 3).These factors are signifi cant contributors to the occurrence of anaemia as confi rmed by mul variate analysis for the risk factors (Table 4).β-thalassaemia and β-thalassaemia trait were excluded during analysis of risk factors for iron defi ciency anaemia.

Discussion
Anaemia adversely aff ects immunity, growth, and cogni ve development, which aff ects school performance and social development 20 .The prevalence of anaemia varies widely between the countries.Diff erent surveys in the past have shown that anaemia is a severe problem in Bangladesh among all ages, popula on and geographic groups 2,21,22 .In this study, 60.7% (n=201) children had anaemia.which is similar to the fi ndings of the Na onal Surveillance Project (NSP) of Helen Keller Interna onal (HKI) in collabora on with the Ins tute of Public Health Nutri on (IPHN) which revealed that overall 68% of Bangladeshi children aged 6-59 months had anemia 23 .The prevalence of anaemia in the neighbouring country of India was 74.3% for 6-35 months age group, Nepal had 78% for 6-59 months age group and in Kazakhstan anaemia prevalence was found to be at 73.7% for 0-23 months age group 24 .This study did not fi nd any gender disparity in the occurrence of anaemia which is in contrast to a similar study done in Bangladesh that found boys to be more anaemic than girls 25 .
In this study, among the anaemic cases, the undetermined cases were 30 (29.7%).With regard to the undetermined cases, it could be argued that as ferri n is an acute phase reactant, it increases by two to four folds in infec ons, which reduces its diagnos c value.So a majority of undetermined cases of anaemia might be a case of IDA which could be detected if subsequent follow up was done.
The occurrence of microcy c anaemia was high in this study.The prevalence of IDA among the anaemic babies has been shown to be higher in other developing countries, such as South Benin, Africa (62%) 26 Argen na (46%) 5 and Pakistan (67%) 27 .The high prevalence of iron defi ciency could be a ributed to the high prevalence of nutri onal inadequacy, intes nal parasite infesta on, and the high consump on of pasteurized unfor fi ed cow's milk in these regions.The prevalence of iron defi ciency, however, is much lower in developed countries, e.g.United States (9%) 28 , and European countries (7%) 29 .The lower prevalence of ID in these developed countries is a ributed to several factors: improved socio-economic status, avoidance of cow's milk feeding during the fi rst year of life, and improvement in the childhood iron nutri on a er implementa on of special supplemental food programmes for women, infants and children (e.g. the WIC programme in USA) 30 .This study also confi rms anaemia to be more common in the low socio-economic class, among whom the adverse consequences of anaemia on health, nutri on and livelihoods are most serious.In this study majority of the anaemic children (66.2%) came from poor and lower middle class family while 35.8% came from upper middle class family (Table 1).
Prematurity, low birth weight and poor complementary feeding prac ces were responsible for anaemia in this age group in Bangladesh.In this study, anaemia was found to be signifi cantly associated with low birth weight and prematurity.Healthy normal weight newborns usually have adequate iron stores up to six months of life, provided they are exclusively breas ed.However, 36% of infants in Bangladesh are born with low birth weight 31 , and with low body iron stores that are quickly exhausted in the fi rst few months of life.Furthermore, only 42% of Bangladeshi infants are exclusively breas ed for six months 32 , and the quality, quan ty and frequency of complementary feeding is inadequate to meet their requirements from six months of age.

Conclusion
A large propor on of hospitalized children under three years were found anaemic.Among all anaemic children IDA, was most common.This study emphasizes the importance of iden fying the risk factors of anaemia in this age group, namely prematurity, low birth weight and poor complementary feeding prac ces.

Recommendation
Raising awareness of the problem and providing eff ec ve health and nutri on educa on in general will be the key interven ons to prevent and control this huge public health problem in Bangladesh.

Table 3 :
Distribu on of the Study Pa ents according to Feeding History (n=320) *Sta s cally signifi cant

Table 4 :
Mul variate analysis of risk factors of anaemia among hospitalized children (n=320)

Table 1 :
Distribu on of the Study Pa ents according to Socioeconomic Status (n=320)

Table 2 :
Distribu on of the Study Pa ents according to Birth History (n=320)