The Journal of Health, Population and Nutrition icddr,b ISSN: 1606-0997 EISSN: 2072-1315 Vol. 28, Num. 5, 2010, pp. 476-483

Journal of Health Population and Nutrition, Vol. 28, No. 5, September-October, 2010, pp. 476-483

Original Paper

Risk factors associated with severe underweight among young children reporting to a diarrhea treatment facility in Bangladesh

Baitun Nahar¹, Tahmeed Ahmed², Kenneth H Brown³, Md. Iqbal Hossain⁴

¹ ICDDR,B, GPO Box 128, Dhaka 1000, Bangladesh; Institute of Mother and Child Health, Uppsala University, Sweden,
² ICDDR,B, GPO Box 128, Dhaka 1000, Bangladesh,
³ Department of Nutrition and Program in International and Community Nutrition, University of California Davis, USA; Helen Keller International, Dakar, Senegal,
⁴ ICDDR,B, GPO Box 128, Dhaka 1000, Bangladesh; Department of Nutrition and Program in International and Community Nutrition, University of California Davis, USA,

Correspondence Address: Md. Iqbal Hossain, Associate Scientist, Clinical Sciences Division and Coordinator, Nutrition Rehabilitation Unit/Mother and Child Health Services, Dhaka Hospital, ICDDR,B, GPO Box 128, Dhaka 1000, Bangladesh , ihossain@icddrb.org

Code Number: hn10062

Abstract

Keywords: Body-weight; Case-control studies; Child; Child nutritional status; Infant; Infant nutritional status; Risk factors; Thinness; Bangladesh

Introduction

Protein-energy malnutrition (PEM) is one of the most serious health problems in Bangladesh and other resource-poor countries where PEM accounts for more than 35% of deaths of children aged less than five years (under-five mortality) and 11% of the total burden of disease ^[1] . Earlier reviews re-ported that severely-underweight children [weight-for-age z-score (WAZ) <- 3], aged 6- 59 months, had more than eight-fold increased mortality ^[2] , and stunting, severe wasting, and intrauterine growth restriction together are responsible for 2· 2 million deaths and 21% of disability-adjusted life-years (DALYs) for children aged less than five years (un-der-five children) ^[1] . The latest national nutrition survey found that 29% of under-five children were moderately underweight (WAZ <- 2 to - 3), and 12% were severely underweight (WAZ <- 3) ^[3] .

The aetiology of childhood malnutrition is com-plex, involving interactions of the biological, cul-tural and socioeconomic factors. In most South Asian countries, poverty, high population density, low status of women, poor antenatal care, high rates of low birth weight, unfavourable child caring practices, and poor access to child healthcare are the underlying contributors to the development of PEM ^[4] , although specific risk factors that can be used for targeting nutrition-intervention pro-grammes have not been well-defined. Therefore, the objective of this study was to compare the char-acteristics of young children with or without severe underweight reporting to a diarrhoea treatment hospital in Bangladesh.

Materials and Methods

The study of young children, aged 6- 24 months, who reported to the Dhaka Hospital of the Interna-tional Centre for Diarrhoeal Disease Research, Bang-ladesh (ICDDR,B) during September 2005-June 2007, with or without severe underweight, used a case-control design. Cases with severe underweight were defined as children of either sex whose WAZ were <- 3. 0 with respect to the new growth stand-ards of the World Health Organization ^[5] and who did not have any congenital anomalies that might have been responsible for their underweight. The controls were children from the same communities who reported to the hospital during the same pe-riod and whose WAZ were >- 2. 5 and length-for-age z-scores (LAZ) were >- 3. 0.

The Dhaka metropolitan area ( 1, 500 sq km) has a total population of ~ 11 million. Each year, the Dhaka Hospital of ICDDR,B provides care and treatment to over 100, 000 patients with diarrhoea, with or without other associated health problems. The hospital also conducts research on enteric and other common infectious diseases and malnutri-tion and provides training on case management of diarrhoeal diseases and malnutrition and research methodology. Under-five children constitute about 60% of the total number of patients, and the ma-jority ( 57%) of the patients come from poor socio-economic communities in urban and peri-urban areas of Dhaka.

Selection of cases and controls

Children enrolled in the study were recruited at the time of their discharge from inpatient treatment for diarrhoea and other acute illnesses. Cases were recruited from children who participated in a study of outpatient treatment of severely-underweight children ^[6] . Children were selected as controls only if they resided in the same neighbourhoods as the cases. Each week/working day, potentially-eligi-ble children who were ready for discharge from the hospital were weighed and measured, and the chil-dren who satisfied the entry criteria for cases and controls were invited to participate in the study. Verbal consent was obtained from a parent, usually the mother of the child.

Collection of data

A research assistant interviewed the mothers using a pretested, structured questionnaire, and a medical doctor examined the children for signs of illness. Information recorded from the interviews includ-ed: age and sex of child, birth-order, number of total and under-five siblings, feeding and immuni-zation history, type of residence and latrine, marital status of mother, monthly family income, and pa-rental age, education, and occupation. The research assistant measured the children′s nude weight, us-ing a frequently-standardized digital scale with 10 g precision (Seca, model- 345, Hamburg, Germany) and recumbent length to the nearest mm, using a calibrated, locally-constructed length board. The same research assistant also measured the weights and heights of mothers, using standard procedures ^[7] . All measurements were taken twice, and the average was calculated; if they varied by more than 100 g for weight or 5 mm for length or height, a third measurement was taken, and the average of the nearest two measures was recorded. The study supervisor checked data forms daily. Anthro-pometric measurements were standardized during monthly refresher training sessions.

Analysis of data

Data were entered using the SPSS software for Win-dows (version 11. 5) (SPSS Inc., Chicago, IL, USA). For normally-distributed continuous variables, means were compared using unpaired t-tests after checking the equality of variance (Levene′s test). For continuous variables that were not normally distributed, the Mann-Whitney U-test was per-formed. The differences in proportions were com-pared by the chi-square test or Fisher′s exact test if the expected number in any cell was ≤ 5. A proba-bility of less than 0. 05 was considered statistically significant. The strength of association of selected risk factors for severe underweight was determined by estimating odds ratios (ORs) and their 95% con-fidence intervals (CIs). All independent variables, e.g. birth-order, number of siblings, socioeconomic status, parental characteristics, and child-feeding and immunization history, were analyzed initially in bivariate models and those that were significant-ly associated with severe underweight (dependent variable), biologically plausible, and not highly in-ter-correlated with each other (r< 0. 8) were included in multiple logistic regression models.

Results

In total, 1, 007 children were studied, of whom 507 were cases and 500 were controls. Their over-all mean±SD age was 12. 6± 4. 1 months, and 44% were girls. There were no significant differences in the mean age or sex ratio in the two groups [Ta-ble 1]. As dictated by the study design, the cases had significantly lower mean weight, length, WAZ, LAZ, and weight-for-length z-score (WLZ) than the control children [Table - 1].

The reported duration of predominant breast-feeding was significantly less among the severe-ly-underweight children [median 4. 0 months; inter-quartile range (IQR) 1. 3- 6. 0] than the con-trol children (median 6. 0, IQR 4. 0- 6. 0, p< 0. 001), and the predominant breastfeeding rate until 5- 6 months was significantly greater among the con-trol children ( 68% vs 38% respectively, p< 0. 001) [Figure - 1]. None of the children in either group was exclusively breastfed until six months. Approxi-mately 15% of the severely-underweight children were never breastfed compared to < 1% of the con-trol children (p< 0. 001). In other bivariate analyses, increasing birth-order, higher number of total and under-five siblings, complete weaning, and ab-sence of BCG, diphtheria, pertussis and tetanus (DPT)/polio, or measles immunization were signifi-cantly associated with severe underweight [Table - 2], [Table - 3] and [Table - 4]. The mothers of malnourished children weighed less and were younger, shorter, less-ed-ucated, and more likely to be divorced or widowed and to work outside the home than the mothers of control children. Similarly, the fathers of malnour-ished children were younger, poorer, less-educated, and more likely to work at lower-paying jobs, such as rickshaw-pulling or day-labour.

The foregoing factors were included in a back-ward stepwise multiple logistic regression model. The regression model revealed that the severely-underweight children were more likely to have a father who had a lower-paying job [adjusted OR (AOR)= 4. 4, 95% CI 3. 1- 6. 1) and less education (< 5 years of education; AOR= 1. 5, 95% CI 1. 1- 2. 2), a mother who was undernourished (BMI < 18. 5, AOR= 3. 7, 95% CI 2. 6- 5. 4), younger (< 19 years, AOR= 3. 0, 95% CI 1. 9- 4. 8), and less-educated (AOR= 2. 7, 95% CI 1. 9- 3. 8), and a family with low monthly income (monthly income of Tk < 5, 000, AOR= 2. 7, 95% CI 1. 9- 3. 8) compared to the control children. Moreover, the malnourished chil-dren were more likely to have a short duration of predominant breastfeeding (< 4 months, AOR= 2. 3, 95% CI 1. 6- 3. 3), to be fully weaned (AOR= 2. 0, 95% CI 1. 1- 3. 5), and to have a higher birth-order (> 3, AOR= 1. 8, 95% CI 1. 2- 2. 7).

Discussion

The results of our study showed that the major risk factors for severe underweight among 6- 2-month-old Bangladeshi children hospitalized for the treat-ment of diarrhoea were related to parental educa-tion, employment, and income; child birth-order; and early child-feeding practices. Some of these fac-tors may operate in common to increase the risk of undernutrition. Fathers of 65. 5% of the severely-underweight children in our study were rickshaw-pullers or day-labourers with little or no formal education. Not only are these occupations the low-est-paid employment categories in Bangladesh but they also often result in erratic incomes, sometimes yielding in little or no earnings on a particular day. Although it is well-documented that level of paren-tal education is positively associated with the nutri-tional status of their children ^[8] , little information is available specifically on the importance of pa-ternal education. Our finding that lower paternal education is a risk factor of severe underweight is in agreement with one other recently-published re-port ^[9] from Bangladesh, which found that educa-tion of father was significantly associated with both moderate and severe childhood stunting. Likewise, a study in Uganda found that both economic status and education of father were significantly associ-ated with the nutritional status of children ^[10] . Re-sults of studies in South India showed that children of fathers who were day-labourers were ~ 3 times more likely to be severely underweight ^[11] .

As with other studies in Bangladesh ^[9],[12] and Afri-ca ^[13] , the present study found that maternal mal-nutrition was an independent risk factor for severe underweight of children. Undernourished mothers often deliver low-birthweight babies ^[14] , and their breastfeeding capacity may also be compromised ^{[15],[16],[17]} ; so, this association is not surprising.

The severely-underweight children in our study were also more likely to have illiterate or less-edu-cated mothers (< 5 years of schooling) as has been observed in previous studies in Bangladesh ^{[9],[12],[18]-,[22]} , and the underweight children were three times more likely to have teen-aged mothers than the better-nourished children. A previous report from Kenya also showed young maternal age to be a risk factor for severe PEM (OR= 3. 95, p< 0. 001) ^[23] . Illit-erate or less-educated and younger mothers usually have less knowledge of appropriate childrearing practices and optimal environmental and personal hygiene, and they generally have less status in the family ^[24],[25] , thereby rendering them less capable of providing adequate childcare and accessing for-mal health services.

Several previous studies examined the relationship between child birth-order and risk of malnutrition, although the results are inconsistent. One recently-published report from Bangladesh found a greater risk of stunting among higher birth-order children ^[9] , and a study in South Africa found higher birth-order (≥ 3) as a risk factor (OR= 2. 3, 95% CI 1. 5- 5. 1) for all forms of severe PEM (marasmus, marasmic kwashiorkor, and kwashiorkor) ^[26] . On the other hand, a study in Egypt did not find any relation-ship between birth-order and undernutrition ^[27] .

Our finding of inadequate/improper breastfeeding as a risk factor corroborates the findings of several other studies in Bangladesh, which reported that inadequate breastfeeding, early supplementation of infant formula or cow′s milk, and early introduction of semi-solid complementary foods were important risk factors for malnutrition ^{[9],[19],[20],[28]} . The hy-gienic and nutritional risks associated with bottle-feeding and artificial milks are well-known ^{[29],[30],[31]} , and previous studies also found that breastfeeding had a significant and substantial impact on overall survival of undernourished children ^[32],[33] . It is also conceivable that the association with a shorter duration of predominant breastfeeding could be an example of reverse causality, whereby children who were ill and malnourished stopped nursing or were provided with other foods. Severely-malnourished children are more likely to have young mothers and to have been born prematurely or with a low birth-weight. Small, premature or malnourished infants tend to breastfeed less often and have a less vigor-ous suck ^[34] . This produces less prolactin release and less production of breastmilk. Young mothers and mothers with low educational level may have less problem-solving skills, leading to an inability to support their infants when food supplies are limited, which, in turn, leads to malnutrition. The cross-sectional design of the present study does not allow us to distinguish between these possibilities.

The risk factors identified for severe underweight can be used, both to design and target preventive interventions. Several factors, such as those relat-ing to infant-feeding practices and birth-order, are potentially modifiable; so, these can be used for designing intervention programmes. For examples, interventions can be developed to motivate behav-iours that are more consistent with recommended feeding practices or to promote adoption of family-planning measures.

The causes of severe underweight are complex and involve the multiple dietary, environmental and other underlying socioeconomic factors, and carefully conceived, broad-based preventive pro-grammes will be necessary to ameliorate the cur-rent situation.

Acknowledgements

The study was funded by Sida-SAREC, Sweden and supported by ICDDR,B and its donors which provide unrestricted support to the Centre for its operations and research. Current donors providing unrestricted support include: Australian Agency for International Development (AusAID), Govern-ment of the People′s Republic of Bangladesh, Cana-dian International Development Agency (CIDA), Embassy of the Kingdom of the Netherlands (EKN), Swedish International Development Cooperation Agency (Sida), and Department for International Development (DFID), UK. The authors gratefully acknowledge these donors for their support and commitment to the Centre′s research efforts. The study was also supported by the Programme in In-ternational and Community Nutrition, University of California Davis and the Fogarty International Center (NIH Research Grant No. D 43 TW 01267).

The authors sincerely appreciate the statistical as-sistance of Dr. Rahman Azari of the Department of Statistics and the advice of Dr. Lucia L. Kaiser of the Department of Nutrition, University of Califor- nia-Davis.

References

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