Introduction
Undernutrition is a major global health problem with estimates in 2017 of 821 million undernourished people(1). Based on 2017 estimates of undernutrition among children aged <5 years, 151 million were stunted and 50 million were wasted(1). Accordingly, nutrition-related factors, especially undernutrition, contributed to approximately 45 % of deaths in children aged <5 years. In sub-Saharan Africa (SSA), <5 years old child death remains the highest in the world(Reference Black, Victora and Walker2), and estimates in 2017 were that globally 15 000 children aged <5 years died every day(3). Ethiopia was among the top five countries for a total number of <5 years old child deaths in 2018, according to a UNICEF report(Reference Keeley, de Oliveira, Zuehlke, Sclama, Vrolijk, Young, Ghebremichael and Anthony4). Moreover, the rates of all types of growth failure (i.e. stunting, wasting and underweight) in Ethiopia remain a public health concern(5). The Ethiopian Somali region has lower stunting and relatively higher underweight and wasting compared with other regional states of Ethiopia(5,Reference Tekile, Woya and Basha6) .
Childhood undernutrition has developmental, economic, social and medical impacts which are serious and lasting, for individuals and their families, for communities and countries(7). Furthermore, lower academic performance in school and cognitive deficit and poor economic development in adulthood are associated with childhood undernutrition(Reference Akombi, Agho and Hall8). An immediate cause of childhood undernutrition is an inadequate intake of nutritious food and a high burden of disease, with numerous underlying contributors. These include food insecurity, poor child feeding practices, lack of improved sanitation and lack of access to quality health and nutrition services, all of which are linked to socio-economic status and sociocultural contexts(Reference Akombi, Agho and Hall8,Reference Vaivada, Gaffey and Das9) .
In pastoral areas of Ethiopia, there has been a growing interest in milk production and consumption; consumers are looking for foodstuffs containing milk and milk products as important contributors to a healthy and balanced diet for children(Reference Sadler and Catley10,Reference Pereira11) . Cow and camel milk (CaM) are the most often consumed milk types for infants and young children; other types such as goat and sheep milk are consumed very rarely by children(Reference Elhadi, Nyariki and Wasonga12,Reference Guliye, Noor and Bebe13) . However, the price of unpasteurised and pasteurised milk is relatively expensive in Somali and Afar regions of Ethiopia as compared with other regional states because of greater demand and more extensive use of milk in their meals(14,Reference Fantu, Bart and Feiruz15) .
In Ethiopian pastoral Somalis, cereal and cereal products are common in children's diets(Reference Fantu, Bart and Feiruz15). Moreover, milk is a staple of the traditional diet of Somali pastoralist children. The milk is obtained from either bovine (BM) or camel (CaM), but CaM is the preferred product that can be used fresh (ma'an), slightly sour (suusa) or sour (garoor)(Reference Guliye, Noor and Bebe13). According to a 2010/11 report, Ethiopia produces about 4 billion litres of milk per year where 83 % is BM followed by 17 % from CaM(16), but per capita consumption is very low, estimated at about 20 litres. CaM can supply required nutrients for child nutrition and eliminate the allergy complications sometimes caused by certain protein fractions in BM(Reference Khatoon, Najam, Khatoon and Najam17). The composition of CaM vs. BM (in g/100 mL) includes: protein (3⋅1 vs. 3⋅5), fat (3⋅5 vs. 3⋅5), ash (0⋅79 vs. 0⋅76) and total solid (11⋅9 vs. 12⋅5), calcium (114 vs. 115 mg/100 mL) and iron (0⋅30 vs. 0⋅04 mg/100 mL).
Furthermore, compared with BM, CaM lacks β-lactoglobulin. However, CaM contains lactoferrin, a protein also found in human breast milk(Reference Al Haji and Al Kanhal18–Reference Alavi, Salami, Emam-Djomeh, Alavi, Salami, Emam-Djomeh and Mohammadian20). These milk nutrients have potential to contribute in explicit ways to the growth process and linear growth of children(Reference Hoppe, Mølgaard and Michaelsen19).
According to several studies, CaM is different from BM in its composition and also has nutraceutical properties. Nutraceuticals found in CaM include insulin-like peptides, lysozymes, lactoferrin and antioxidative vitamins(Reference Alavi, Salami, Emam-Djomeh, Alavi, Salami, Emam-Djomeh and Mohammadian20,Reference Dubey, Lal and Mittal21) with antidiabetic, hypoallergenic, antihypertensive, anticancer and antimicrobial effects with substantial benefits for human health as a functional food(Reference Khatoon, Najam, Khatoon and Najam17,Reference Alavi, Salami, Emam-Djomeh, Alavi, Salami, Emam-Djomeh and Mohammadian20,Reference Abdel Gader and Alhaider22,Reference Khalesi, Salami and Moslehishad23) . To date, there are several studies conducted on BM consumption and childhood undernutrition in developed and developing countries(Reference Grenov and Michaelsen24); however, to our understanding, there is a gap regarding the associations between CaM or BM consumption and growth failures in Ethiopia and elsewhere. Therefore, the main aim of the present study was to compare the prevalence of growth failures between CaM and BM consumers. Secondly, we investigated associations between CaM or BM consumption and other predictors of growth failures in rural pastoral districts of Somali, Ethiopia.
Methods and materials
Study design, setting and sampling
A community-based comparative cross-sectional study was carried out among 388 pre-schoolers, aged 24–59 months from November to December 2018. For the present study, two pastoral districts, namely Degahabour and Harorays, were randomly selected from high camel and cattle population districts, respectively.
The sample size required for the study was estimated to be 369 children by using a single population proportion formula based on 60 % anaemia among <5 years old children in a previous study(25), 95 % confidence level and 5 % margin of error. Adding 10 % non-response rate, the final sample size was 406 including both CaM- and BM-consuming pre-schoolers. The sample was equally allocated to the two strata by the source of milk being consumed by children.
A multistage sampling technique was employed. The districts were selected randomly from those with camel or cattle populations. Then the study kebeles (smallest administrative units) were selected randomly from each district. Households in each kebele were stratified by the source of milk given to their children (CaM vs. BM). The presence of a lactating camel or lactating cow in the household was obtained from health extension workers and was taken as a marker to stratify the households. From each stratum, a child aged 24–59 months was selected randomly at each household. If more than one eligible child was present in the household, a child was selected by the lottery method. Researchers were not blind to the source of milk consumed by the child, because interviews and measurements were done at the household level.
Data collection
Socio-demographic, economic, water, sanitation and hygiene, as well as milk feeding practices, were collected by individual interviews of mothers by trained data collectors fluent in Af-Somali and English. The questionnaire was pre-tested in kebeles other than the study kebeles before the data collection. Additionally, mothers were asked if their child had consumed food from a list of seven food groups on the previous day from the time that the child awakened until the child slept. The food groups were (i) cereals, tubers or roots; (ii) meat, poultry and fish (flesh foods); (iii) milk and dairy products; (iv) eggs; (v) nuts/legumes; (vi) vitamin A-rich fruits or vegetables; (vii) other fruits and vegetables. These seven categories are among the food groups suggested for evaluating diets of children(Reference Swindale and Bilinsky26).
Blood biochemical assessments
A finger prick blood sample was collected from each child according to WHO guidelines(27). Haemoglobin (Hb) concentration was measured using HemoCue (Hb 301 model) with regular calibration following manufacturer's instructions (HemoCue Ltd, Sheffield, UK). A child with an Hb value of <11 g/dLwas considered as anaemic(28). The use of the HemoCue has been validated in field studies, and the coefficient of variation has been reported as 3⋅9 %(Reference Neufeld, García-Guerra and Sánchez-Francia29). All children diagnosed with anaemia were immediately referred to local health facilities for further treatment.
Anthropometric measurements
The researcher and assistant conducted anthropometric measurements of each child at home. The height and weight measures were taken twice with bare feet and light clothes following standard procedures. Child age was obtained from a parental recall using an events calendar. Body weight was measured with a SECA Model 874 electronic digital weighing scale (Seca GmbH & Co KG, Hamburg, Germany) to the nearest 0⋅1 kg. The scale was calibrated at least twice a day against a standard weight. The height was measured in an erect position to the nearest 0⋅1 cm using a calibrated portable SECA stadiometer (Seca GmbH & Co KG, Hamburg, Germany). During measurement of the height, the head was positioned at the Frankfurt plane and the four body parts (heel, calf, buttocks and shoulder) touched the vertical stand of the stadiometer. Using the WHO growth standards(30), weight-for-age, height-for-age and weight-for-height z-scores were determined using WHO Anthro version 3.1.0(31) for children aged <5 years.
Data analysis
Frequency distributions and confidence intervals (CIs) were calculated for child and household characteristics. Additionally, frequencies for these characteristics were calculated based on the type of milk consumed. Furthermore, frequencies for food group consumption and anthropometric indices also were calculated for the group as a whole as well as based on the type of milk consumed. Pearson's χ 2 test was used to determine associations with the background characteristics, food group consumption and milk source. Independent sample t-tests identified significant differences in each of the anthropometric indices based on the type of milk consumed. For the analysis of factors predicting growth failure, the normality of continuous data was checked by the Kolmogorov–Smirnov test. The potential predictors for anthropometric measurements were identified by bivariate analysis with P < 0⋅05 for inclusion in the multivariable analysis model. Multicollinearity was checked using the variance inflation factor (VIF) statistic, with VIF > 10 as the indication of multicollinearity for the logistic regression model. A forward Wald stepwise model was developed, and odds ratios were used to evaluate factors associated with child growth. All statistical analyses were performed with SPSS version 20 (IBM, Armonk, NY, USA), and statistical significance was reported at P < 0⋅05.
Results
The mean (sd) age of the children was 38⋅5 (10⋅2) months. Slightly more than half of the study participants were boys. About two-thirds of children were fed breast milk beyond 2 years and more than nine in ten children were ever breastfed. Moreover, more than half of pre-schoolers consumed milk ≥4 times/week (Table 1).
Table 1. Percentage distribution of child and household characteristics among CaM- and BM-consuming pre-schoolers in Somali region, Ethiopia
a Physically or chemically treated.
b Wash hands after defaecation and cleaning child faeces or before cooking and breastfeeding.
Almost all mothers of the pre-schoolers had never attended school, more than three-fourths were self-employed/home-workers and 60⋅6 % had greater than or equal to seven persons in a household. About 61⋅7 % of children were living in households with no toilet/latrine, 44⋅3 % drank unsafe/unimproved water and 8⋅8 % drank untreated water. Moreover, nearly one-fourth of mothers never washed their hands after defaecation or before cooking and breastfeeding.
Substantially more than half of children in both CaM and BM strata were fed breast milk beyond 2 years of age. A higher proportion of BM consumers had milk four or more times in a week period than did CaM consumers. In total, 75 % of BM consumers but fewer than 45 % of CaM-consuming children were anaemic as presented in Table 1.
We also found that a significantly higher proportion of pre-schoolers who consumed either CaM or BM used modern health facilities than traditional health facilities. More children who consumed CaM than BM reported health problems in the last 2 weeks; however, more CaM-consuming children reported safe/improved water sources in the household than did BM-consuming children.
Food group patterns among children consuming CaM and BM
In the present study, the major food sources for children in the pastoral districts were dairy products and grains, roots and tubers (Table 2). Very few (0⋅8 %) pre-schoolers consumed eggs, 16⋅5 % consumed flesh foods, 16⋅8 % consumed other fruits and vegetables and 22⋅4 % consumed vitamin A-rich fruits and vegetables. Only three CaM consumers and no BM-consuming pre-school children ate eggs in the present study. In addition, both CaM- and BM-consuming pre-school children had in general low flesh foods (i.e. meat, fish, poultry and liver/organ meat) and other fruits and vegetables. However, CaM-consuming children had significantly lower flesh foods and higher other fruit and vegetable intakes as compared with BM- consuming children in the 24 h preceding the day of our interview as presented in Table 2.
Table 2. Food group consumption patterns of pre-schoolers aged 24–59 months in rural pastoral districts of Somali, Ethiopia
Anthropometric measures by milk source
Stunting, underweight and wasting prevalence in the rural districts of Somali are presented overall and by CaM or BM consumption strata in Table 3. Overall, 24⋅1 % (95 % CI 20⋅5, 28⋅3) of pre-schoolers were stunted, 34⋅8 % (95 % CI 29⋅9, 39⋅6) were wasted and 34⋅7 % (95 % CI 30⋅1, 39⋅9) were underweight. Moreover, a higher proportion of pre-schoolers consuming BM were stunted (72 vs. 28 %; P < 0⋅001) and underweight (70⋅1 vs. 29⋅9 %; P < 0⋅001) compared with CaM consumers. In contrast, the prevalence of wasting was more similar and not significantly different between BM and CaM consumers. In BM compared with CaM-consuming pre-schoolers, significantly higher severe stunting (76 vs. 24 %; P = 0⋅002), severe wasting (66 vs. 34 %; P = 0⋅048) and severe underweight (78 vs. 22 %; P < 0⋅001) were observed.
Table 3. Pre-school children aged 24–59 months – anthropometric measures by milk source in rural pastoral districts of Somali, Ethiopia
Note: CI; confidence interval; severe stunting: height-for-age z-score (HAZ) < −3 sd; any stunting: HAZ < −2 sd; severe underweight: weight-for-age z-score (WAZ) < −3 sd; any underweight: WAZ < −2 sd; severe wasting: weight-for-height z-score (WHZ) < −3 sd; any wasting: WHZ < −2 sd.
Factors predicting childhood undernutrition
After adjusting with covariates in the multivariable logistic regression model, the odds of stunting were more likely to be higher among anaemic children [adjusted odds ratio (AOR): 4⋅22; 95 % CI 2⋅23, 7⋅98], and children who consumed BM (AOR: 2⋅10; 95 % CI 1⋅22, 3⋅61) compared with those children without anaemia and who consumed CaM. Being a girl reduced odds of stunting by 43 % compared with boys (Table 4).
Table 4. Factors associated with stunting, wasting and underweight in rural pastoral districts of Somali, Ethiopia
a Factors tested in the model: drinking water source, anaemia, milk source, breastfed ever, health care facility, time spent to fetch water, age of child, sex of child and frequency of milk consumed per week.
b Factors tested in the model: water treatment in the household, drinking water source, health care facility, time spent to fetch water, monthly income, anaemia, milk frequency consumed per week, dietary diversity, milk source and sex of child.
c Factors tested in the model: drinking water source, anaemia, milk type, breastfed ever, health care facility, time spent to fetch water, age of child, sex of child and water treatment in the household
Similarly, the odds of underweight were more likely to be higher among anaemic children (AOR: 2⋅27; 95 % CI 1⋅38, 3⋅72), children who consumed BM (AOR: 1⋅97; 95 % CI 1⋅20, 3⋅24) and who drank unsafe water (AOR: 1⋅91; 95 % CI 1⋅19, 3⋅07) compared with children without anaemia who consumed CaM and drank safe water.
Wasting was significantly associated with drinking unsafe and untreated water in households (P = 0⋅003 and P = 0⋅04), respectively. Drinking unsafe water (AOR: 1⋅93; 95 % CI 1⋅25, 2⋅95) and drinking untreated water (AOR: 2⋅77; 95 % CI 1⋅03, 7⋅44) in the household increased odds of wasting by nearly twice and more than twice, respectively, compared with those who drank safe and treated water.
Discussion
The overall growth failure of pre-schoolers was high in the present study with 24⋅1 % of pre-schoolers being stunted, 34⋅8 % were wasted and 34⋅7 % were underweight. Stunting was less than the national figure (38 %), while wasting and underweight were higher than the national rates of 10 and 24 %(5), respectively. A higher prevalence of stunting was reported in some parts of Ethiopia such as Amhara(Reference Gashu, Stoecker and Bougma32), Bule Hora district(Reference Asfaw, Wondaferash and Taha33) and Belesa district of northwest Ethiopia(Reference Fentahun, Wubshet and Tariku34) which ranged from 27⋅6 to 57⋅7 %; these higher numbers might suggest poor child care practices and lack of access to health facilities(Reference Rohner, Northrop-clewes and Tschannen35). However, a lower prevalence of stunting was observed in Gambia (15⋅7 %) and Wolayta-Sodo, Southern Ethiopia (22⋅2 %) as compared with our present result(Reference Petry, Jallow and Sawo36,Reference Eshete, Abebe and Loha37) .
In the present study, wasting was threefold higher compared with several results reported in other parts of Ethiopia such as Amhara, Bule Hora district, Wolayta-Sodo, Southern Ethiopia, Belesa district, northwest Ethiopia and in Gambia(Reference Gashu, Stoecker and Bougma32–Reference Fentahun, Wubshet and Tariku34,Reference Petry, Jallow and Sawo36,Reference Eshete, Abebe and Loha37) that ranged from 5⋅5 to 16 %. Similarly, lower childhood underweight was reported as compared with the present study in several studies(Reference Gashu, Stoecker and Bougma32,Reference Petry, Jallow and Sawo36,Reference Abdulahi, Shab-Bidar and Rezaei38) . On the other hand, higher childhood underweight was found in a study in India(Reference Panda, Sadhu and Pramanik39).
Milk is known to provide essential nutrients for growth during childhood, but available nutrients differ by milk sources. CaM has positive nutritional and health benefits compared with BM because of its easy digestion and absorption for children(Reference Alavi, Salami, Emam-Djomeh, Alavi, Salami, Emam-Djomeh and Mohammadian20,Reference Singh, Mal and Kumar40) . In our present study, children who consumed BM were more vulnerable to stunting and underweight as compared with CaM consumers. Several studies and reviews report that CaM has antimicrobial and antiparasitic factors as well as inflammation inhibitors that have beneficial effects to reduce childhood stunting and underweight(Reference Dubey, Lal and Mittal21,Reference Abdel Gader and Alhaider22,Reference Singh, Mal and Kumar40) . Moreover, CaM has potential to reduce nutrition-related iron deficiency anaemia by providing ten times higher concentrations of iron and five times higher vitamin C as compared with BM(Reference Alavi, Salami, Emam-Djomeh, Alavi, Salami, Emam-Djomeh and Mohammadian20) which could contribute to the reduction of childhood stunting and underweight. Furthermore, CaM has higher concentrations of insulin-like growth factor-1 and growth-promoting nutrients like zinc and niacin relative to BM(Reference El-Hatmi, Jrad and Salhi41).
In general milk consumption in childhood has long been assumed to be positively associated with growth. This association may be due to the nutritious content of milk such as high levels of proteins and micro- and macronutrients as well as high calcium and the insulin-like growth factor-1 that are of major relevance for children's development and growth(Reference Pereira11,Reference Hoppe, Mølgaard and Michaelsen19) . In the present study, more than half of pre-schoolers consumed milk more than four times in a week which might support childhood growth. However, a significantly lower proportion of CaM-consuming pre-schoolers had milk ≥4 times/week compared with BM consumers. This might be an explanation for the higher intakes of the other fruit and vegetable food groups by the CaM consumers than BM consumers as presented in Table 2 of the present study.
Our present study showed that 9⋅8 % of pre-schoolers were severely stunted, 12⋅2 % were severely wasted and 14⋅0 % were severely underweight. The children who consumed CaM had a lower proportion of severe stunting, wasting and underweight than BM consumers. CaM's effect on the reduction of infections caused by parasites and pathogenic microorganisms could have contributed to these differences(Reference Abdel Gader and Alhaider22,Reference Ennani and Hidane42,Reference Prabhurajeshwar and Chandrakanth43) .
Our present results showed that boy pre-schoolers were more stunted than girls. Sex differences in pre-school children's height status also have been reported in low-income countries such as Guatemala, Senegal and various SSA countries(Reference Bork and Diallo44–Reference Tumilowicz, Habicht and Pelto46). Perhaps boys are more vulnerable to health inequalities than their girl counterparts in the same age groups(Reference Wamani, Åstrøm and Peterson45). The study finding was also consistent with previous research that reported boy children were more vulnerable to stunting because they required comparatively more calories for growth and development(Reference Akombi, Agho and Hall8,Reference Demissie47,Reference Khan, Zaheer and Safdar48) . One of the reasons for low caloric intake in children might be low socio-economic status, based on findings in Pakistan and SSA(Reference Akombi, Agho and Hall8,Reference Khan, Zaheer and Safdar48) . Similarly, a study conducted in Guatemalan indigenous children showing that boys required greater energy intakes than girls could also make them more likely to be vulnerable for stunting with low socio-economic status(Reference Tumilowicz, Habicht and Pelto46).
The odds of childhood stunting significantly increased with anaemia as compared with non-anaemic children. The likelihood of increased childhood stunting due to anaemia is consistent with several studies from low- and middle-income countries such as Ethiopia, Gambia, Guinea and China(Reference Petry, Jallow and Sawo36,Reference Woodruff, Wirth and Ngnie-teta49–Reference Yang, Li and Li51) . Anaemia may lead to increased susceptibility to childhood stunting by decreasing food intake, and thus inadequate satisfaction of required iron from the diet might have negative impacts on children's growth(Reference Soliman, De Sanctis and Kalra52,Reference Sachdev, Gera and Nestel53) . Additionally, the risk of underweight was significantly higher among anaemic children compared with non-anaemic. This result was consistent with previous findings that showed an increase in underweight in children with anaemia(Reference Engidaye, Melku and Yalew54) and, thus, may be associated with poor intake of family food rich in iron and loss of appetite because of anaemia infection(Reference Mohammed, Larijani and Esmaillzadeh50).
The odds of childhood stunting and underweight significantly increased in BM-consuming as compared with CaM-consuming pre-schoolers. To our understanding, there has not been a comparative study of the effects of BM and CaM consumption on child growth, but some studies have shown that milk consumption could contribute to anaemia and stunting in young children(Reference Mohammed, Larijani and Esmaillzadeh50,Reference Ziegler55) . However, reports have indicated that CaM has unique potential for nutraceutical and therapeutic activities against different conditions such as anaemia, parasitic infections and milk protein allergies related to β-lactalbumin as compared with BM(Reference Khatoon, Najam, Khatoon and Najam17,Reference Dubey, Lal and Mittal21,Reference Singh, Mal and Kumar40,Reference El-Hatmi, Jrad and Salhi41,Reference Korish, Abdel Gader and Al Haider56–Reference Maryniak, Hansen and Ballegaard59) that could reduce stunting and underweight among the pastoralist children. Additionally, CaM has been fed as a human milk substitute in some studies(Reference Alavi, Salami, Emam-Djomeh, Alavi, Salami, Emam-Djomeh and Mohammadian20) and has had antimicrobial effects(Reference Ennani and Hidane42,Reference Al-nabulsi, Olaimat and Osaili60) .
For pre-schoolers in the present study, the odds of being wasted or underweight were between two and three times higher among children who drank unsafe/unimproved/untreated water in their household. A systematic review of studies in SSA and a report based on Demographic Health Survey data in Guinea found similar results(Reference Akombi, Agho and Hall8,Reference Woodruff, Wirth and Ngnie-teta49) regardless of the milk type to be consumed by pre-schoolers. Unsafe and unimproved water is not free of pathogens and these could contribute to childhood illness, wasting and underweight. In sustainable development goal 2030, target 6⋅1 aims to ensure universal and equitable access to safe and affordable drinking water for all(61); however, adequate safe and improved water sources for Somali rural pastoralist children remain limited and are immense challenges putting them at risk of loss of nutrients due to diarrheal diseases and contribute childhood undernutrition.
Among limitations, cross-sectional data were used for our present study analyses; thus, temporal relationships could not be characterised in the pathways from milk intake to child growth. Also, we could not differentiate causal relations on the outcomes. We did not demonstrate a mechanism by which CaM improved child growth compared with BM, but presented fact-based evidence about characteristics of CaM. We have not collected detailed child infection information. We suggest further characterisation of CaM and evaluation of its impact on the health and growth of children with well-designed clinical trials.
Conclusion
Lower prevalence of stunting and underweight were observed among CaM-consuming compared with BM-consuming pre-schoolers. Severe growth failures of all types persisted among BM consumers. Both milk type and anaemia status predicted childhood stunting and underweight. Drinking water sources were significant predictors of both wasting and underweight of pre-schoolers. Being girls significantly reduced the odds of childhood stunting. Promoting CaM consumption for pre-schoolers in pastoralist and agro-pastoralist areas may be helpful to curb the high rates of undernutrition in the Somali region.
Acknowledgments
We are highly delighted to acknowledge each rural district health office administrator and local leaders who allowed the study to be conducted. We also thank Degahabour and Jigjiga University Referral Hospitals for providing their laboratories. We also acknowledge Jigjiga and the Ministry of Science and Higher Education for their funding. Moreover, we highly appreciate caregivers/mothers who agreed to participate in the present study and also the data collectors.
A.M. conceived the study, developed the tool, coordinated the data collection activity, carried out the statistical analysis and drafted the manuscript. T.B., B.J.S. and D.H. were involved in statistical analysis, reviewing and editing the manuscript and guiding the study. All authors read and approved the final manuscript.
The present study was funded by the Ministry of Science and Higher Education and Jigjiga University. The funding organisations were not involved in the design, data collection, analysis and interpretation of the study.
Ethical approval was obtained from the Institutional Review Board of the College of Medicine and Health Sciences, Hawassa University (Ref. No. IRB/137/10, dated 12 February 2018). Permission to collect data in Degahabour and Haroreys districts was obtained from the respective health bureaus. Oral and written consent was obtained from the mother for each child participating in the study after the research purpose and objectives were explained. The mothers were told to withdraw whenever they wished to stop participation during the data collection.
The authors declare that they have no competing interests.
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