Contribution of water, sanitation, hygiene and basic education to reduce under-five mortality in Sudan

The Millennium Development Goals (MDGs) were adopted in 2000, within which the MDG4 targeted a reduction of under-five mortality (U5MR) by two-thirds in 2015 against its level in 1990. High-income countries achieved the U5MR reduction target while many low-income countries, including Sudan, lagged far behind. In 2015, the Sustainable Development Goals (SDGs) were adopted for the period 2015–2030 with 17 goals as a framework for good health and prosperity in all countries. SDG 3.2 targeted the reduction of U5MR to 25 per 1,000 live births by 2030 (UN 2021). The MDG7 of environmental sustainability already targeted halving the proportion of people without access to safe drinking water and basic sanitation by 2015. Later, SDG6.1 targets full access to clean water, while SDG6.2 targets universal access to sanitation and hygiene (UN 2018).

Improved water and sanitation services were described as the most effective interventions to reduce child mortality (Van Maanen 2009) and investments in water and sanitation are highly cost-effective, even when only the mortality benefits are taken into consideration (Günther & Fink 2011). Improved water and sanitation services were also acknowledged in reducing health risks and contributing to good health (Hutton & Varughese 2016). Nevertheless, Haller et al. (2007) found that various interventions for improving water and sanitation facilities were cost-effective, especially in developing countries with high mortality rates, but with substantially varying cost-effectiveness ratios, ranging from US$20 per DALY averted for disinfection at the point of use to US$13,000 per DALY averted from improved water and sanitation facilities. Pruss-Ustun et al. (2008) confirm that one-tenth of the global burden of disease (GBD) could be prevented by improving water, sanitation and hygiene (WASH) management, and Fink et al. (2011) found that access to improved sanitation and water was associated with lower mortality and lower risk of child diarrhea and stunting. In developed countries such as England and the USA, and lately in low-income countries, major reductions in mortality have been associated with rising incomes, improvements in nutrition and public health, medical care and vaccinations (Cutler et al. 2006). Importantly, the largest global mortality declines over the period 1970–2016 were found to occur among children under 5 years of age (GBD 2017). WHO (2020) estimates that in 2019 death among under-five children was 5.2 million, mostly from preterm birth complications, pneumonia, congenital anomalies, diarrhea and malaria, which can all be prevented or treated with access to affordable interventions including immunization, adequate nutrition, safe water, food and quality care.

Despite their proven effectiveness, spending on sanitation and hygiene services has been low in low-income countries. For example, Mara & Evans (2018) showed that until 2015, the percentage of people practicing handwashing-with-soap was very limited at 15% in Sub-Saharan Africa (SSA) and relatively high at 76% in North Africa. The authors estimated average costs to achieve the hygiene and sanitation targets during 2016–2030 in SSA at US$35.5 billion annually. Such costs are apparently beyond the economic capabilities and affordability of low-income countries. Waddington & Cairncross (2021) state that respiratory infections and diarrhea are the main causes of child deaths in low-income countries, closely related to improved WASH, noting that studies rarely focus on mortality. Reliable WASH has also been recognized as a critical precondition for a safe school environment for high-quality education and healthy development of children (Van Maanen 2009; Karon et al. 2017; WHO 2019a, 2019b). From a systematic review and meta-analysis, Wolf et al. (2022) found that WASH interventions significantly reduce the risk of diarrhea in children in low- and middle-income countries (LMICs) whether through supplying filtered water, improved water quality from improved sources or through basic sanitation services with sewer connection. Furthermore, Mwai et al. (2022), in the case of Kenya found that safely managed WASH services were an essential part of preventing and protecting human health during infectious disease outbreaks, including the COVID-19 pandemic.

Economic growth in terms of total income and per capita incomes is widely perceived as affecting human health positively through the ability to invest and spend on health and health care. In a meta-analysis of studies from developing countries, O'Hare et al. (2013) found that an increase in GDP per capita by 10% in the country reduces its infant mortality to 45 per 1,000 live births. Hanf et al. (2014) confirmed immediate associations between children's death rates, national income, and access to sanitation facilities. Generally, spending on health inputs from all sources is supposed to promote human health in terms of reduced mortality rates. However, differences in public health spending were found to account for only 0.15% of cross-country differences in health status, and child mortality differences were found largely to be related to income levels and female education (Filmer & Pritchett 1997), and the effectiveness of medical services is constrained by other socio-economic factors (Filmer & Pritchett 1999). In a cross-sectional model for 117 countries, Zakir & Phanindra (1999) found that infant mortality rates were significantly affected by GNP per capita, fertility, and female education, but not by government expenditure on health care. Education and social capabilities have been identified as major drivers of health outcomes rather than healthcare spending (Caldwell 1986; Lleras-Muney & Sherry 2008). Alemu (2017) for 33 African countries found that a 1% increase in access to improved sanitation reduces infant mortality by two infant deaths per 1,000 live births, and showed that declines in infant mortality rates were significantly brought about by improvements in education and economic growth. Abdelhafidh (2018) for 93 countries over the period 1995–2012 showed that health expenditure has a positive effect on reducing child mortality in countries with higher income only. Cardona et al. (2022) showed for 129 LMICs that decreases in GDP per capita increased U5MR deaths in 2020, with most deaths occurring in SSA countries, calling for urgent interventions in nutrition and food, environmental factors, and comprehensive primary health care.

Positive effects of incomes on U5MR are mostly indirect and can be channeled through countries' abilities to provide safe WASH services, basic education facilities, food, vaccination and medical care for the improvement of child health, which vary with development stage (Preston 2007). For example, low income levels in SSA countries are commonly associated with low levels of accessibility to such basic services, resulting in higher levels of U5MR compared with those in high-income countries (WHO 2020). Furthermore, the transmission mechanisms of effects of incomes and public spending on children's health occur in a complex setting of environmental, demographic, technological, educational and medical factors which all lead to differences in child mortality outcomes between rich and poor countries (Hobcraft et al. 1984; Woods et al. 1989; Cutler et al. 2006; Watson 2006). Together with improved income levels, improvements in environmental and socio-demographic factors, including WASH, have led to a steady decline in the total number of under-five deaths. Globally, U5MR declined from 90.6 per 1,000 live births in 1990 to 42.5 in 2015 (You et al. 2015). The GBD (2019a, 20219b) showed that under-five deaths have declined from 9.6 million in 2000 to 5.0 million in 2019, amounting to a reduction of 47.9% over that period. In Sudan, U5MR declined from 136.6 per 1,000 live births in 1990 to 65.9 in 2015 (World Bank 2021), a year in which it had to be reduced to 42.1 per 1,000 live births. If the SDG3.2 is to be met, the U5MR in Sudan should be reduced by 5.04% per year from its 2020 level to reach 25 per 1,000 live births by 2030.

Slow reduction of U5MR is linked to child and maternal malnutrition, which has been highly prevalent in most low-income African countries and identified as the main mortality risk factor in most SSA regions (GBD 2019a, 2019b). In Sudan, the prevalence of stunting in children under five has only decreased from 40.8% in 2000 to 33.7% in 2020. The prevalence of anemia in women of reproductive age (15–49 years) in Sudan was also very high, estimated at 42.9% in 2000, and reduced to 36.5% in 2019. Abu-Manga et al. (2021) estimated that 36.35% of children under 5 years of age in the country were stunted in 2018. Chiopris et al. (2024) stated that 3.3 million children in Sudan suffered from acute malnutrition between 2018 and 2019, and malnutrition of children in Sudan has been influenced by food insecurity, inadequate access to clean water and sanitation, limited healthcare services, poverty, and conflicts. These unfavorable factors are more likely aggravated by climate change with major impacts on WASH services. Drinking water quantity and quality are also affected by climate change as documented by Sharma et al. (2021) for the case of Nepal, noting that very few policies and laws have incorporated climate change-resilient WASH as a priority, and urged for interventions for adaptation and mitigation of climate change impacts on WASH.

In sum, it appears that in low-income countries, including Sudan, lack of access to safe WASH services, malnutrition of children and low enrollment of children in basic education are the main factors behind a major portion of child morbidity and mortality. The question is thus, how do improvements of these factors contribute to the reductions of U5MR in Sudan? Answering this question provides policy implications on how best to promote reductions in child mortality rates in Sudan and for other low-income countries to move forward in achieving child health's SDGs.

The objectives of this study are (a) to examine the role of access to WASH services and basic education in reductions of U5MR in Sudan, in view of the role of economic growth and health care, and (b) to simulate the required progress in WASH services, economic growth and health care based on their 2015 actual values in order to move forward to achieve the SDG3.2 of reducing U5MR to 25 per 1,000 livebirths in Sudan by 2030.

Sudan's real GDP was estimated at 12 billion US dollars in 1990, which increased to 78 billion in 2015, and to 85 billion in 2020. However, the percentage of people living under the poverty line defined as 1.5 US dollars per head in 2009 was estimated at 46.5%, which should have been reduced to 23.2% in 2015. According to the World Bank (2020), 43.0 and 75.2% of Sudanese were deemed poor against the international poverty lines of $3.2 and $5.5 per person per day, respectively. Since 1992, the healthcare system has been administratively and fiscally decentralized, with a reduced share of government spending on health and education. This implied that public and private spending on health has been insufficient to contribute to the requirements of the child health MDG targets, despite the achieved economic growth. Over the period 1990–2020, Sudan's GDP grew at an annual average of 4.69%, total health expenditure grew an average of 5.86%, per capita government health expenditure grew an average of 3.95%, while per capita private health expenditure grew an average of 6.93%. Sudan started to experience some demographic transition indicated by declining fertility and U5MR, as well as increasing overall life expectancy. Government health expenditure as a percentage of GDP ranged between 0.3% to 0.7% between 1990 and 2012, and remained the same at 0.7% in 2020, despite the introduction of social health insurance in 1994. Meanwhile, out-of-pocket expenditure (OOP) represented 75% of per capita private health spending and has been increasing faster than per capita public health expenditure. OOP is shown to be catastrophic and pushes a large portion of Sudan's households into poverty (Ebaidalla 2021).

Sudan's performance in enrollment in basic education and in access to drinking water, sanitation and hygiene (WASH collectively) has been historically low with low quality of these services. In 1990, the basic education enrollment rate was 55.47%, increased to 57.84% in 2000, and stood at 73.21% in 2020. Until 2020, 30% of the households have access to proper sanitation, while 68% of households have access to improved drinking water sources, and just about a third of households have simultaneous access to both of them, with wide disparities amounting to more than 35% between urban-rural areas (UNICEF 2020). Access to hygiene services in Sudan in terms of handwashing-with-soap was estimated at 34.0% for the urban population and at 21.8% for the rural population in 2020, together with 29.2% of the population practicing open defecation according to a document on Sudan's water and sanitation profile released by the Africa Finance Ministers’ Meeting 2020.

Sudan has national strategies to control communicable diseases as the main causes of mortality, namely malaria, tuberculosis, diarrhea and respiratory infections, particularly among children. An HIV/AIDS control plan has been in effect since 2004, and a tuberculosis (TB) policy has been in place since 2007. The TB immunization coverage rate among children aged 12–23 months was 74% in 2010 and increased to 93% in 2015. Children under the age of five with acute respiratory infection (ARI) who received health care increased from 57.3% in 2000 to 90.1% in 2006 but massively dropped to 43.3% in 2014 (World Bank 2021). Within the government's (2007–2011) health sector strategy as part of Sudan's 25-year health reform, the resources deployed seem insufficient to meet the MDG4 by 2015. Sudan is a country with prolonged armed conflicts, drought and increasing environmental degradation causing mass displacement and loss of livelihoods. These unfavorable factors hinder progress in reducing U5MR, particularly when public and private economic abilities and WASH services are far less than sufficient in quantity and quality.

Improvements in WASH and basic education services as well as health care are expected to lead to reductions of U5MR. Of the economic growth factors, the exchange rate is expected to worsen U5MR, for two reasons. First, badly managed depreciation of the national currency against the US dollar and instability of exchange rate disrupt imports of medical and pharmaceutical products and their supply and demand in the local market. Secondly, the depreciated value of the Sudanese currency reduces purchasing power, especially among the poor, and thus limits children's access to essential WASH, enrollment in basic education and health care when needed. GDP growth and an increase in foreign aid are supposed to lead to lower U5MR.

For estimation of the ARDL bounds test model specified in Equation (2), it is required to test the properties of the time series data, namely the stationarity, or the absence of unit roots property. For this purpose, the study applies the Augmented Dickey–Fuller (ADF) and Phillps–Perron (PP) unit root tests.

Results of estimations from the ADF and PP show that all variables are stationary after first differencing I(1) except ISF, MMR and AID which are stationary at both the level I(0) and first difference as presented in Table 1. Given the relatively long time span of the time series used and the instability of the Sudan economy over the period 1969–2020, the study investigates the order of integration of the variables with structural breaks, under the scenario of innovational outlier. The variables U5MR, ISF, MMR, THE, IMZ and AID are found to be integrated at both I(0) and I(1), while the other variables are integrated at the order I(1) only as presented in Table 1.

Table 1 shows that most of the breaks occurred during the 1990s (seven breaks) followed by the 2000s (four breaks), reflecting two decades of high instability in the economic and health environment of Sudan. The first variable to witness a break was the foreign aid in 1974, followed by IMZ in 1980. U5MR witnessed a break in 1991. The last variable to break is the health expenditure in 2008. It is thus concluded that with breaks and without breaks, the time series data of the study follow a combination of order of integration at I(0) and I(1). Accordingly, it is appropriate to use the ARDL bounds test model to investigate the long-run equilibrium and short-run dynamics of U5MR. Given the structural breaks identified, we introduced a dummy variable (DU) associated with U5MR, which takes 0 until 1991 and 1 for the rest of the period. The dummy variable also accommodates the role of institutions, which are expected to be dysfunctional over 40 years of war in Sudan within the study period of 1969–2020. A vector autoregressive (VAR) model is estimated, which gives an optimal lag order of 3, used for the estimation of the ARDL model for the U5MR as the dependent variable, according to the criteria presented in Table 2.

The bounds test results for U5MR are summarized in Table 3.

The reliability and validity of the estimated ADRL model for the determinants of U5MR are confirmed by performing the tests of normality, autocorrelation, heteroscedasticity and stability where the test results are presented in Table 4. Given that the cointegration of the variables of the study is confirmed by the ARDL bounds test results, we investigated the short-run dynamics and long-run behavior of U5MR with its explanatory variables. The results are presented in Table 4.

The empirical results show that declining U5MR in the long run in Sudan have been driven mainly by access to sanitation and basic education, with a collective factor of −1.79, but this effect is reduced by a factor of 0.56 associated with the accessed drinking water on U5MR, which reflects its lack of safety. Economic growth variables play a secondary role, which collectively reduces U5MR by a factor of −0.21. Health care, namely the number of physicians per 1,000 people and total health expenditure, contribute the least in the explained reductions of U5MR with a factor of −0.18. Devaluation of the Sudanese currency against the US dollar by 10% is found to increase U5MR by 6%. A reduction of the mother mortality ratio by 10% is found to reduce U5MR by 7%. An increase in foreign aid by 10% reduces U5MR by 2%, while the increase in GDP in itself by 10% is found to increase U5MR by 13%. In the short run, U5MR decelerates itself by a coefficient of (−0.56), but the accessed drinking water is found to worsen U5MR, with a coefficient of (0.57). Access to sanitation and education reduces U5MR with a coefficient of (−0.06). Total health expenditure and GDP growth worsen U5MR with a combined coefficient of (0.12). Immunization reduces U5MR with a coefficient of (0.04). The dummy variable is positively interacting with U5MR, indicating dysfunctional institutions amid 40 years of civil wars in Sudan, which have been leading to direct and indirect child deaths.

Upon the empirical results of this study, we simulated the required progress in the relevant variables in Sudan toward achieving SDG3.2. Specifically, access to safe drinking water has to be increased by 4.26%, sanitation by 7.52%, hygiene (HYG) by 6.3%, enrollment in basic education by 2.68%, total health expenditure by 0.45%, number of physicians per 1,000 persons by 0.12, immunization coverage of children by 0.72% and prevalence of stunting in children under 5 years has to be reduced by 2.8% per year in order to reduce U5MR from 56.2 in 2020 to 25 per 1,000 livebirths in 2030 as presented in Table 5. Meeting these targets requires real GDP growth of 4.86% per annum, WASH investments of $US 32 million annually between 2020–2030, and stable exchange rate in the range of 81–86 Sudanese bounds per 1 US dollar. This amount of investments in WASH sectors compares with required financing totaling 18,293 million US dollars to sustain Sudan SDG6 according to a document on Sudan's water and sanitation profile released by the Africa Finance Ministers’ Meeting (2020).

Globally, and in high-income countries, declines in U5MR have been remarkable within the context of the MDGs, which are the milestones to meet SDG3.2. Sudan experienced slow reductions of U5MR and missed achieving the MDG4 by the end of 2015, and the country is very unlikely to move forward in the SDGs of child health unless major steps are taken to improve WASH services in an integrated policy package alongside improvement of incomes, mother health, child nutrition and health care. This is evident from the empirical findings of the bounds test cointegration method which confirmed co-movement between U5MR, access to drinking water, sanitation separately and basic education, health care and economic growth. The empirical results show that declining U5MR in Sudan, in the long run, has been driven mainly by access to WASH, specifically sanitation facilities, and by basic education. The enrollment in basic education's effect on child health is found to be in line with Lleras-Muney & Sherry (2008). Economic growth factors are found to play a secondary role in reducing U5MR in Sudan, while health care factors are found to contribute the least to reductions of U5MR. Arguably, the relatively lower effect of economic growth and health care on U5MR in Sudan is attributable to the low access of the population to WASH services and to children's undernutrition. In fact, our results are not in accord with Bishai et al. (2016), who found that improvements at aggregate in and outside the health sector contribute equally to child and maternal mortality reductions in a sample of 146 developing countries. Partially, our results on the effect of total health expenditure are not in line with Novignon et al. (2012) who found that public expenditure leads to a reduction of infant mortality rates in 44 SSA countries including Sudan. Since OPP health expenditure is high and impoverishing to households in Sudan, it might have reduced the effectiveness of total health expenditure per capita in the country as in the case of Thomas & Neumayer (2013). A reduced mother mortality ratio of 10% is found to reduce U5MR by 7%, indicating how important the survival of a mother is to the survival of her children, confirming Pavard et al. (2007) and Atrash (2011).

In the short run, the U5MR reducing effects of WASH in terms of access to sanitation and basic education are in line with Elwasila (2020) who finds that these basic services play the leading role in development in Sudan. However, the accessed drinking water is found to worsen U5MR, which could be due to insufficiency of water services and/or low quality or contaminated drinking water, which affects child health negatively through waterborne diseases such as diarrhea and cholera. In fact, it has been repeatedly reported in the news that the piped drinking water in Sudan's urban areas is being accidentally mixed with the sewage water, with changes in drinking water taste and smell. It becomes evident that there is an urgent need to develop a national drinking water safety strategic framework, along with a sanitation and hygiene policy in an integrated package of safe WASH services. The U5MR adjusts to steady-state equilibrium by a factor of 43% each year, reflecting a slow reduction toward the targeted MDG4 by 2015, let alone moving forward to the SDG3.2.

The study concludes that the collective contribution of WASH in terms of access to drinking water, sanitation and basic education is almost 4.5 times higher than the collective contribution of economic growth and health care to reductions of U5MR in Sudan. In other words, WASH and basic education are the leading factors in reducing U5MR in Sudan, while economic growth and health care appear to play a secondary role in reducing U5MR, and their effectiveness seems to depend on progress in WASH services. The policy implication is that without the promotion of access to safe WASH services provided as an integrated package, Sudan will not move further in filling the gap of the MDG4, let alone in improving child health in the context of SDG3.2. Quality number of physicians, full vaccination of children and economic growth (stable and inclusive) can be more effective in reducing U5MR in Sudan, provided that failures in the provision of safe drinking water and sanitation within a WASH strategy and inclusive primary education are synergistically addressed. Resources allocation for child health from national and foreign sources needs to be increased but their effectiveness in health outcomes needs genuine assessment.

The major limitation of this study is its utilization of aggregate data at the national level of Sudan on ten variables and thus controlling all the confounders is not possible to adjust due to limited data. Thus, the empirical findings of this study are only relevant at the national level. This leaves investigation of the role of WASH on U5MR at the urban-rural level, or by State and socio-demographic factors for further research. In addition, important variables such as hygiene and child nutrition were not included explicitly in the empirical model of U5MR, due to the unavailability of complete data on these two variables over the period of study. Nonetheless, the validity of the estimated ARDL econometric model is confirmed by the conventional tests of the absence of autocorrelation, non-existence of heteroscedasticity and the model's stability. However, further studies using survey data, cross-sectional, longitudinal and panel data with multivariate methods are vital in the case of Sudan, in order to validate the findings of the current study on determinants of U5MR in Sudan.

All relevant data are available from an online repository or repositories: https://databank.worldbank.org/source/world-development-indicators#.

The authors declare there is no conflict.