Factors associated with stunting among children below five years of age in Zambia: evidence from the 2014 Zambia demographic and health survey

Stunting continues to be a major public health problem globally. A child is ‘stunted’ if his or her height is less than negative two standard deviations below the World Health Organization standard [1]. Globally, about 161 million children under the age of 5 years are stunted while 51 million children do not weigh enough for their height (wasted), and are not in healthy state [2]. Over the years, the prevalence of stunting has reduced but overall progress is insufficient and many children are still at risk. The prevalence of stunting is highest in developing countries, that is, in Asia and Africa where stunting is more prevalent than underweight or wasting. According to UNICEF [3], 40% of children in Eastern and Southern Africa, under 5 years of age are stunted. Stunting has not spared Zambia. According to the recent Zambia Demographic and Health Survey (ZDHS), about 40% of children under-age five are stunted with Northern Province having the highest prevalence at 49% [4].

Long-term restriction of a child’s potential growth brought about by insufficient nutritious food intake coupled with poor health conditions can lead to stunting. Stunting may start as early in pregnancy, infancy and early childhood due to poor quality nutritional diets that may lead to inadequate nutrient intake. Furthermore, poor socio-economic conditions and increased risk of frequent exposure to certain conditions, such as illness or inappropriate feeding practices may give rise to high levels of stunting [5]. Adequate intake of nutrients is, therefore, essential for growth and mental development and long-term good health.

Consequences of stunting include short adult height, effect on health and negative impact on economic development over time [6]. Stunting has long-term effects on individuals and societies; including diminished cognitive and physical development reduced productive capacity and poor health, and an increased risk of degenerative diseases such as diabetes [3]. For instance, short adult height among women has an impact on the health and survival of their children while for men it may even result in low economic productivity. The government of the Republic of Zambia has put in place measures to address the high levels of stunting through child nutrition programmes and Policies such as the National Food and Nutrition Strategic Plan. Some nutrition programmes include infant and young child feeding, management of acute malnutrition, micronutrient deficiency control and hygiene, water and sanitation. However, despite the spelled out commitments and programmes, stunting still remains considerably high among children aged under 5 years in Zambia compared to WHO standards.

In Zambia, information concerning factors associated with stunting has been very scanty and limited. There is, therefore, need to adequately shed more light on why Zambia continues to experience high levels of stunting. The resulting findings would inform policy and programmes. Stunting has a number of implications on children, which later manifests into adulthood and negatively impact the nation as a whole. Thus, the purpose of this study was to identify socio-economic factors that were associated with stunting among children aged 0 to 59 months in Zambia.

The study included 12,328 children aged 0–59 months who had their height and age measured. The results showed that 4937 (40%) children under 5 years of age were stunted. Northern Province had the highest prevalence of stunting while Lusaka province had the lowest. Figure 1 below shows prevalence of stunting across the country by province.

Table 3 summarizes the results of the backward stepwise logistic regression models, which measured the net associations of all the independent variables with stunting. For characteristics that remained significant in the model, the odds ratios did not change substantially from the bivariate analysis. Child’s sex was significant for predicting stunting. Children in rural areas were 19% less likely to be stunted compared with children living in urban areas (AOR = 0.81, 95%CI: 0.70, 0.95; p < 0.05), While children aged 24 to 35 months of age had 7 times higher odds of being stunted compared with children less than 6 months. The analysis showed that, child’s sex, child age, mothers’ age and level of education, residence, improved source of drinking water and duration of breastfeeding were significant for predicting stunting.

Early childhood development is crucial especially the first 1000 days of an infant’s life after which stunting is irreversible. Long-term effects of stunting include diminished cognitive and physical development, poor health and adult short stature. The study intended to identify the factors associated with stunting among children aged 0 to 59 months using latest ZDHS data. The prevalence of stunting among children under five was 40% and was more prevalent among male children than female children. This finding is similar to other studies conducted around the world that have also documented higher prevalence of stunting in boys than in girls [7–9]. According to Chirande et al. [5] sex differences could also be attributed to behavioural patterns of communities for instance, favouritism towards daughters. Additionally, epidemiological evidence depicts boys to be biologically more vulnerable to morbidity [10, 11].

Over the years studies have observed that populations that live in rural areas have been more susceptible to nutritional deficits due to a number of disadvantages however, according to the results of the present study, children in urban areas had a higher risk for stunting than children in rural areas. Our study agrees with other studies that found similar results [12, 13]. This risk of stunting in urban areas might be due to decreased maternal contact time due to work schedules of working mothers that may bring about short period of breastfeeding, early cessation of breastfeeding and improper complementary food, which have a largely negative effect on the growth of the children. This entails that most of the urban population might actually be urban poor who live in informal settlements/unauthorised slums in abject poverty, poor water and sanitation, high food insecurity and limited nutritious foods. Rural populations may have opportunities to grow nutritious rich foods while urban poor are highly dependent on food purchase and diets lack diversity. On the contrary, our study contradicts other studies that have revealed no significant association between urban or rural location [14, 15]. There is, therefore, need of establishing strategies that facilitate proper nutrition and child health in urban areas especially among the poor.

Mother’s education continues to be associated with stunting. Higher odds of stunting being observed among children whose mothers had no education. The same has been confirmed in previous studies and the results imply that maternal education may provide protective effects against all under-nutrition indicators in children [5, 14, 16, 17]. Mothers who are more educated are more likely to be more conscious about their children’s health. Moreover, due to exposure to media they are likely to have better child and healthcare knowledge of nutrition leading to better feeding practices. However, other studies show contrary results in that there was no significant association between stunting and maternal education [18, 19]. While most studies have shown that maternal education is a determinant of a child’s nutritional status, other studies have actually indicated that father’s education is equally an important factor for child nutrition [20, 21]. Therefore, the importance of maternal education might vary from country to country and the difference may be probably due to differences in study design and as well as different socio-economic statuses of countries.

In relation to mother’s age, the differences in prevalence of stunting decreased with maternal age. Lower odds of stunted were observed among children whose mothers were aged above 35 years old. The study results corroborate with other studies [5, 22]. This may be because young mothers require adequate nutrition for them to grow into adults and as a young mother; food shared in small proportion between the infant and the mother is not adequate. In addition, younger mothers may tend to have poor knowledge and practices of good nutrition for young children.

Water and sanitation also has a significant impact on child nutritional status as lack of water in households makes basic hygiene somewhat unattainable. In the present study, stunting was significantly associated with improved source of drinking water. Children whose source of drinking water was non-improved were likely to be stunted compared to children whose source of water was improved. This may be attributed to the fact that non-improved water sources may be contaminated and thus may increase risk of infection such as diarrhoea. The study findings are consistent with other studies [23–26]. However, the study findings are also contrary to previous studies [16, 18, 27, 28], that depict no significant association between source of drinking water and stunting.

In relation to number of children in the household, smaller families are generally socio-economically advantaged accompanied by improved quality of life. In the present study, although the highest OR for stunting correspond to children belonging to families with six or more children the same was not confirmed in the multiple analysis after adjustment by other factors. These results are contrary to other studies [9, 22, 29, 30], which observed a significant relationship between stunting and number of under five children in a household.

Type of delivery assistance and place of delivery showed significant statistical relations in the bivariate analysis, however, with respect to multiple logistic regression analysis they did not show statistical significance. In this study type of delivery assistance and place of delivery were, therefore, statistically insignificant factors with regard to the association with stunting.

The present study had a number of limitations. Firstly, an in-built limitation of cross-sectional data is their snapshot nature that makes establishing a temporal sequence of events and drawing causal inferences difficult as this pertains to the period and season the survey was undertaken. A few key variables could not be included because of difference in classifications, as data was collected and classified by ZDHS team. For instance, the ZDHS only classifies urban residence as urban even though it includes peri-urban areas thus the definition was not precise. Although the study excluded other key variables from the analysis, our model did reflect all those variables linked to childhood stunting. The ZDHS often has a delay in publishing results, which implies that information might not be a true reflection of the current situation.

Stunting is associated with factors including nutrition, socio-economic, demographic and environmental factors that impact on children’s health and wellbeing. These factors often not only influence stunting but also influence nutritional status of a child. Therefore, improvements in maternal education, household wealth, diet diversity, water and sanitation could improve health status of children. Stunting affects health status and productivity later in adult life. Thus, the consequences of socio-economic inequalities in childhood nutritional status are likely to be recurring. Therefore, with this information on factors associated with stunting, there is need to address all causes of stunting in an integrated manner. Policies and programmes should also give greater attention to improving maternal education especially among younger mothers, improve social-economic status and improve water sources, sanitation and hygienic practices.