Effect of Drinking Water and Sanitation on Child Undernutrition and Diarrhea in Lao PDR

Abstract

Childhood undernutrition and diarrhea remain a global health burden in the 21^st century. We assessed the effect of access to basic drinking water and sanitation at home on reducing children’s likelihood of being undernourished and experiencing diarrhea in Laos. We pooled two rounds of nationally representative cross-sectional household surveys: the Lao Social Indicator Surveys 2011/2012 and 2017, encompassing 23 070 children aged <5 years. We employed multivariate multilevel logistic regression for the analysis. The results showed that access to basic drinking water was associated with a reduced likelihood of undernutrition and was effective in improving child undernutrition. Moreover, access to basic sanitation reduced diarrhea in addition to undernutrition. Notably, sanitation facilities only mitigated childhood stunting and diarrhea when basic drinking water facilities were present in the household. We also confirmed that socio-economic disparities existed among children accessing basic drinking water and sanitation. Consequently, further efforts are needed toward equitable access to these facilities in Laos.

Keywords

drinking water sanitation child undernutrition diarrhea Laos

What We Already Know

Undernutrition and diarrhea remain a great threat to children in low- and middle-income countries.

Access to water, sanitation, and hygiene (WASH) is considered an important factor in determining children’s health.

Newborns, infants, and young children are most vulnerable to inadequate WASH.

What This Article Adds

Access to basic drinking water at home was associated with a lower likelihood of undernutrition in children, and access to basic sanitation was confirmed to be effective in reducing diarrhea in children in addition to undernutrition.

While access to basic drinking water effectively improved child nutrition, sanitation facilities were effective in reducing the likelihood of childhood stunting and diarrhea only when basic drinking water facilities were also present in the household.

Socio-economic disparities existed in children’s access to basic drinking water and sanitation, and thus further expansion of WASH services is critical for improving child health and achieving health-related SDGs in Laos.

Introduction

Child undernutrition is highly prevalent and remains a global health burden in the 21^st century. An estimated 22.0% or 149.2 million and 6.7% or 45.4 million children aged <5 years were stunted (height-for-age z-scores [HAZ] below −2) and wasted (weight-for-height z-scores [WHZ] below −2) worldwide in 2020.¹ Undernutrition increases the risk of mortality, mobility, illness, infection, developmental delay, and cognitive deficits in early childhood.² In addition, it has detrimental effects on human capital development, decreases educational attainment, and lowers labor productivity in later life.^3,4 Therefore, investment in child nutrition not only to enhances children’s current well-being but also bolsers human capacity in the long run.⁵

Target 2.2 of the Sustainable Development Goals (SDGs) stipulates that “By 2030, end all forms of malnutrition, including achieving, by 2025, the internationally agreed targets on stunting and wasting in children aged <5, and address the nutritional needs of adolescent girls, pregnant and lactating women, and older persons.”⁶ Regarding the determinants of child undernutrition, the United Nations Children Education Fund’s (UNICEF) conceptual framework categorizes them into three main factors: immediate, underlying, and basic causes.⁷ Among these, water, sanitation, and hygiene (WASH) are considered to be the underlying causes. Children who lack access to safe WASH services are more susceptible to infections and are thus more likely to be undernourished.⁸

In addition to undernutrition, reducing diarrheal cases among children remains a global challenge, as diarrhea is one of the leading causes of child mortality worldwide. According to the current estimate, diarrhea accounts for 8% of all deaths among children aged <5 years, which is equivalent to approximately 525 000 deaths.⁹ Most diarrhea-induced child deaths are attributed to dehydration caused by the loss of a large amount of water and electrolytes from the body in liquid stools. Approximately 88% of global deaths from diarrhea are caused by unsafe water, unhygienic environments, and inappropriate toilets.⁹ Therefore, the provision of safe WASH services is a key strategy for preventing diarrhea.

Lao People’s Democratic Republic (Laos), a landlocked country in mainland Southeast Asia, is one of the least-developed countries. The prevalence of child undernutrition in Laos ranks among the highest in the region. For instance, the prevalence of stunting among children in Laos (30.2%) was higher than that in Cambodia (29.9%) and Myanmar (25.2%) in 2020.¹⁰ The percentage of people who had basic drinking water services in Laos increased from 77% in 2015 to 85% in 2020.¹¹ Similarly, the percentage of people with basic sanitation increased from 70% to 79% during the same period.¹¹ Although several studies have explored the determinants of child nutritional status in Laos,^12
-14 little is known about the effects of WASH services on child nutrition. Regarding diarrhea, while there is a study examining hygiene practices,¹⁵ no empirical study has examined the effects of sanitation on children’s diarrhea using nationally representative data in Laos. Therefore, we investigated the effects of access to basic drinking water and sanitation at home on undernutrition and diarrhea in children in Laos. Our analysis is expected to help policymakers improve child health by guiding effective WASH programs.

Methods

Data

We pooled the two latest rounds of nationally representative cross-sectional data from the Lao Social Indicator Surveys (LSIS)-I (2011/2012) and LSIS-II (2017). The LSIS applied the technical frameworks of the Multiple Indicator Cluster Survey (MICS). The MICS collects data using standardized questionnaires. We ensured that the same definitions and survey instruments were used for both surveys, LSIS-I and LSIS-II, before pooling the data. In April 2010, the Prime Minister’s Office issued Letter of Approval No. 730 to the Ministry of Health for the conduct of LSIS, then the ethical protocols for the surveys were approved by the Lao Statistics Bureau, Government of Laos.^16,17 Prior to the questionnaire survey, verbal consent was obtained from all adult respondents or parents/guardians of minors. They were informed of the voluntary nature of participation and the confidentiality and anonymity of information.^16,17 A total of 18 843 households were surveyed for the LSIS-I from October 2011 to February 2012,¹⁶ and 22 287 households were interviewed for the LSIS-II from July 2017 to November 2017.¹⁷ We used data from 23 070 children aged <5 years as the study sample.

Drinking Water and Sanitation

Based on the World Health Organization (WHO)/UNICEF Joint Monitoring Program report,¹¹ the LSIS defines basic drinking water as “piped water (located in dwelling, compound, yard, or plot to neighbor, public tap/standpipe), boreholes/tube wells, protected dug wells, protected springs, rainwater, and packaged or delivered water.”^16,17 Basic sanitation facilities is defined as “flush/pour flush toilets (connected to piped sewer systems, septic tanks, or pit latrines), ventilated improved pit latrines, pit latrines with slabs, and composting toilets.”^16,17

In our study, we defined an explanatory variable of “basic drinking water” taking 1 if a child’s household had access to basic drinking water facilities, and 0 otherwise. Similarly, we defined “basic sanitation” as 1 if the household had basic sanitation facilities, and 0 otherwise. In addition, we used an interaction term “Basic drinking water × Basic sanitation.” This variable takes 1 if the household has both basic drinking water and basic sanitation, and 0 otherwise. Including this interaction term allowed us to analyze the interaction effect between drinking water and sanitation. Moreover, we can examine the conditions under which drinking water and sanitation can be effective in relation to each other.

Nutritional Status

We employed three widely used anthropometric measures as outcome variables for child undernutrition: HAZ, weight-for-age z-score (WAZ), and WHZ, which correspond to standard deviations from the median of a reference population. HAZ is a longer-term index that represents linear growth of a child and often used as an index of chronic undernutrition or “stunting.” WAZ provides information about both acute and chronic undernutrition, indicating “underweight.” WHZ is a shorter-time index that indicates acute undernutrition or “wasting.” Wasting is usually caused by a recent nutritional deficiency and manifests as seasonal variations according to a change in the availability of food or disease prevalence. A child whose HAZ, WAZ, or WHZ is more than 2 standard deviations below the median of the reference population is classified as moderately “stunted,” “underweight,” or “wasted,” respectively.

Diarrheal Disease

In the LSIS, the incidence of diarrhea in children was determined based on responses from mothers or caretakers to the question of whether the child had exhibited symptoms of diarrhea in the 2 weeks preceding the survey.^16,17 Specifically, diarrhea was determined by the perception of the mother or caretaker, or by the occurrence of three or more loose or watery stools per day, or by the presence of blood in the stool, or a frequency greater than what was normal for the child. We defined the variable “Diarrhea” as an outcome measure. It was operationally defined as a binary variable: 1 indicated the presence of a diarrheal symptom in the 2 weeks preceding the survey, or 0 otherwise.

Control Variables

As control variables, we used several variables other than WASH, which are potentially significant determinants of child health outcomes. These variables span child-, mother-, household-, and regional-level characteristics. Child-level variables included sex and age (0-4 years old). Mother-level variables comprised age and educational achievement (categorized as none, primary, secondary, and higher). Household-level variables covered the ethnicity of the household head (Lao-Tai, Mon-Khmer, Hmong-Mien, others) and wealth quintiles. Regional-level variables included province-specific dummies. In addition, we included a round dummy variable of the LSIS to account for time-speciﬁc shocks common across all regions at the time of the survey. The selection of these covariates was based on UNICEF’s analytical framework on the causes of child nutrition⁷ and empirical studies on child nutrition^12
-14 and diarrhea in Laos.¹⁵

Statistical Analysis

To assess the effect of children’s access to drinking water and sanitation on their nutritional status and diarrheal symptoms, we conducted multivariate multilevel logistic regressions. Specifically, we used two-level multilevel models that included mother-specific and community-specific random effects in the estimated equation, accounting for unobserved heterogeneities at both the mother and community (cluster) levels. These models operate on the premise that the nutritional status of children born to the same mother is not independent of each other due to the unobserved biological factors of the mother. Likewise, unobserved community characteristics such as beliefs, cultural practices, social networks, gender issues, legal policy, and other local contextual factors may affect child nutrition. In addition, we performed a logistic regression analysis to explore the factors associated with children’s access to drinking water and sanitation services at home. The detailed statistical analysis plan is available for reference in the supplementary material. Regression analysis was performed using Stata version 16. We used the svy (survey) commands to correct for unequal sampling probability, clustering, and stratification to calculate sample characteristics because the LSIS applied a two-stage cluster sampling design.

Results

Sample Characteristics

Table 1 presents the sample characteristics. Regarding outcome variables, the proportions of children who were stunted, underweight, and wasted were 33.9%, 29.6%, and 6.8%, respectively. Two weeks prior to the survey, 8.3% of the children had experienced a diarrheal episode. Concerning the main predictors, 74.9% and 57.2% of the children had access to basic drinking water and sanitation services at home, respectively. Accordingly, approximately half (50.3%) of the children had access to both basic drinking water and sanitation.

Table 1.

Sample Characteristics of the Children Aged <5 Years in Laos.

Variables	Observation	Mean
Outcome variables
Stunting	21 981	0.339
Underweight	22 370	0.296
Wasting	22 045	0.068
Diarrhea	22 770	0.083
Main predictors
Basic drinking water	23 070	0.749
Basic sanitation	23 064	0.572
Both drinking water and sanitation	23 064	0.503
Covariates
Girl	23 070	0.491
Child age (years)
0	22 787	0.201
1	22 787	0.192
2	22 787	0.199
3	22 787	0.213
4	22 787	0.196
Mother’s age	23 070	28.4
Educational attainment of mother
None	22 976	0.283
Primary	22 976	0.397
Secondary	22 976	0.242
Higher	22 976	0.078
Ethnicity of the household head
Lao-Tai	23 070	0.486
Mon-Khmer	23 070	0.197
Hmong-Mien	23 070	0.150
Other	23 070	0.167
Wealth quintile of the household
Lowest	22 787	0.297
Lower middle	22 787	0.220
Middle	22 787	0.178
Upper middle	22 787	0.156
Highest	22 787	0.148
Province
Vientiane capital	23 070	0.089
Phongsaly	23 070	0.032
Luangnamtha	23 070	0.028
Oudomxay	23 070	0.066
Bokeo	23 070	0.032
Luangprabang	23 070	0.072
Huaphanh	23 070	0.054
Xayabury	23 070	0.047
Xiengkhuang	23 070	0.054
Vientiane	23 070	0.068
Borikhamxay	23 070	0.041
Khammuane	23 070	0.054
Savannakhet	23 070	0.146
Saravane	23 070	0.077
Sekong	23 070	0.024
Champasack	23 070	0.082
Attapeu	23 070	0.022
Xaysomboune	23 070	0.011
Round
LSIS-I (2011-2012)	23 070	0.496
LSIS-II (2017)	23 070	0.504

Stunting: height-for-age z-score (HAZ) < −2SD, Underweight: weight-for-age z-score (WAZ) < −2 SD, Wasting: weight-for-height z-score (WHZ) < −2SD, Diarrhea = 1 if a child had a diarrheal symptom in the 2 weeks prior to the survey, or 0 otherwise.

Abbreviation: LSIS, Lao Social Indicator Surveys.

Regression Analysis

Table 2 presents the results of the multivariate multilevel logistic regression analysis of the effects of drinking water and sanitation on child undernutrition and diarrhea. The magnitude of the effects was assessed by adjusted odds ratio (aOR), which is interpreted as increasing the likelihood of being undernourished or having diarrhea (if aOR > 1) or reducing that likelihood (if aOR < 1), after controlling for potential confounders. Model 1 reports the estimated effects of basic drinking water. The estimated aOR for stunting (aOR = 0.862, P = .002) indicated that if the child had access to basic drinking water, the odds of the child being stunted decreased by 0.138. Similarly, favorable effects of basic drinking water were confirmed for underweight (aOR = 0.901, P = .036) and wasting (aOR = 0.836, P = .035). Nevertheless, no significant effect was observed for diarrhea (aOR = 0.956, P = .536). Model 2 shows the estimated effect of basic sanitation. Children with access to basic sanitation were less likely to be stunted (aOR = 0.875, P = .011), underweight (aOR = 0.824, P < .001), wasted (aOR = 0.849, P = .078), and have diarrhea (aOR = 0.862, P = .063). Model 3 reports the estimated interaction effects between drinking water and sanitation. The estimate of the interaction term indicated that no interaction effects were confirmed for any of the outcome variables. The estimates for basic drinking water in Model 3 indicate whether it affects the outcome variable in the absence of basic sanitation. The results showed that access to basic drinking water had a statistically significant effect on the outcome variables except for diarrhea, as in Model 1. In contrast, the statistical significance of basic sanitation on the likelihood of stunting and diarrhea disappeared in the absence of basic drinking water compared with Model 1.

Table 2.

Results of Multivariate Multilevel Logistic Regressions Analyzing the Effects of Access to Basic Drinking Water and Sanitation on Childhood Undernutrition and Diarrhea in Laos.

	Outcome variables
	Stunting		Underweight		Wasting		Diarrhea
	aOR	P	aOR	P	aOR	P	aOR	P
	[95% CI]	P	[95% CI]	P	[95% CI]	P	[95% CI]	P
Model 1
Basic drinking water	0.862 [0.78, 0.95]	.002	0.901 [0.82, 0.99]	.036	0.836 [0.71, 0.99]	.035	0.956 [0.83, 1.10]	.536
Model 2
Basic sanitation	0.875 [0.79, 0.97]	.011	0.824 [0.74, 0.92]	.000	0.849 [0.71, 1.02]	.078	0.862 [0.74, 1.01]	.063
Model 3
Basic drinking water × Basic sanitation	0.940 [0.78, 1.14]	.520	1.078 [0.89, 1.31]	.450	1.197 [0.86, 1.67]	.292	0.958 [0.72, 1.28]	.774
Basic drinking water	0.891 [0.79, 1.00]	.059	0.889 [0.79, 1.00]	.059	0.791 [0.64, 0.97]	.027	0.982 [0.82, 1.17]	.840
Basic sanitation	0.929 [0.78, 1.11]	.408	0.785 [0.66, 0.94]	.009	0.753 [0.55, 1.03]	.073	0.893 [0.68, 1.17]	.411
Observation	21 977		22 366		22041		22 765

Abbreviations: aOR, adjusted odds ratio; CI, confidence interval.

Using the aOR, we can calculate the attributable risks (AR) of childhood undernutrition and diarrhea associated with the lack of drinking water facilities, while controlling for potential confounders. The calculated ARs are as follows: stunting (−2.44%); underweight (−1.66%); wasting (−0.99%); and diarrhea (−0.30%). This implies that children with access to drinking water at home exhibit a 2.44% lower risk of being stunted compared to those without such access. For instance, within a population of 1000 children, ensuring access to home drinking water facilities could prevent 24 children from experiencing stunting. The time required for changes to manifest varies by indicator. Specifically, stunting is a long-term indicator, spanning from several months to years; wasting is a short-term indicator, spanning from several weeks to months; and underweight falls within an intermediate time frame. Similarly, ARs for childhood undernutrition and diarrhea in relation to the absence of sanitation facilities are computed as follows: stunting (−2.19%); underweight (−3.08%); wasting (−0.88%); and diarrhea (−0.98%).

Table 3 presents the results of logistic regression analysis to identify factors that were associated with children’s access to basic drinking water and sanitation facilities at home. It shows that higher educational levels of the mother and household wealth levels were associated with a higher likelihood of accessing basic drinking water and sanitation at less than 1% significance levels. Regarding ethnicity, children from the Mon-Khumer, Hmong-Mien, and other ethnic groups were less likely to have access to basic drinking water than those from the Lao-Tai group. A similar tendency was observed for access to sanitation, except for children from the Mon-Khmer group. Looking at the estimates of province, it was observed that compared to Vientiane capital, children in Luangnamtha, Oudomxay, Huaphanh, and Xiengkhuang provinces had a higher likelihood of having access to it, while in the other provinces, the probability tended to be lower. On the contrary, no province had a higher likelihood of children’s access to sanitation facilities than Vientiane capital, and the likelihood was statistically and significantly lower in the eight provinces.

Table 3.

Results of Logistic Regression Analyses Examining Factors Associated With Children’s Access to Basic Drinking Water and Basic Sanitation Facilities at Home in Laos.

	Outcome variables
	Basic drinking water		Basic sanitation
	aOR	P	aOR	P
	[95% CI]	P	[95% CI]	P
Girl	1.031 [0.96, 1.10]	.377	1.045 [0.97, 1.13]	.247
Child’s age (years)
0^a
1	1.012 [0.91, 1.13]	.828	0.982 [0.87, 1.11]	.770
2	0.999 [0.90, 1.11]	.992	0.996 [0.88, 1.12]	.949
3	0.982 [0.88, 1.09]	.744	1.003 [0.89, 1.13]	.963
4	0.999 [0.90, 1.11]	.980	0.976 [0.86, 1.10]	.691
Mother’s age	1.008 [1.00, 1.01]	.000	1.013 [1.01, 1.02]	.000
Mother’s education
None^a
Primary	1.207 [1.11, 1.31]	.000	1.496 [1.36, 1.64]	.000
Secondary	1.536 [1.36, 1.73]	.000	2.087 [1.84, 2.36]	.000
Higher	1.740 [1.35, 2.25]	.000	2.287 [1.72, 3.04]	.000
Ethnicity
Lao-Tai^a
Mon-Khmer	0.748 [0.67, 0.84]	.000	0.965 [0.85, 1.10]	.588
Hmong-Mien	0.604 [0.53, 0.69]	.000	0.558 [0.48, 0.65]	.000
Other	0.828 [0.74, 0.93]	.001	0.777 [0.68, 0.89]	.000
Wealth quintile
Lowest^a
Lower middle	1.539 [1.41, 1.68]	.000	4.985 [4.53, 5.48]	.000
Middle	2.291 [2.06, 2.54]	.000	18.148 [16.1, 20.5]	.000
Upper middle	5.557 [4.79, 6.44]	.000	98.287 [81.4, 118.6]	.000
Highest	49.869 [33.1, 75.2]	.000	1077.349 [601.6, 1929.2]	.000
Province
Vientiane capital^a
Phongsaly	1.156 [0.80, 1.67]	.436	0.334 [0.18, 0.61]	.000
Luangnamtha	7.034 [4.46, 11.1]	.000	1.062 [0.58, 1.95]	.847
Oudomxay	1.475 [1.03, 2.12]	.035	0.683 [0.38, 1.24]	.213
Bokeo	0.599 [0.42, 0.86]	.006	1.049 [0.57, 1.94]	.878
Luangprabang	0.662 [0.46, 0.95]	.023	0.599 [0.33, 1.10]	.097
Huaphanh	2.253 [1.55, 3.28]	.000	1.058 [0.58, 1.92]	.853
Xayabury	0.774 [0.53, 1.14]	.191	1.610 [0.86, 3.02]	.137
Xiengkhuang	1.738 [1.19, 2.53]	.004	0.880 [0.48, 1.61]	.678
Vientiane	0.773 [0.54, 1.11]	.165	0.927 [0.50, 1.72]	.810
Borikhamxay	0.652 [0.45, 0.94]	.023	1.052 [0.57, 1.95]	.874
Khammuane	0.321 [0.23, 0.45]	.000	0.114 [0.062, 0.21]	.000
Savannakhet	0.260 [0.19, 0.36]	.000	0.093 [0.052, 0.17]	.000
Saravane	0.426 [0.30, 0.60]	.000	0.062 [0.034, 0.11]	.000
Sekong	0.968 [0.68, 1.38]	.856	0.440 [0.24, 0.80]	.007
Champasack	0.642 [0.45, 0.92]	.015	0.088 [0.048, 0.16]	.000
Attapeu	0.486 [0.34, 0.69]	.000	0.136 [0.074, 0.25]	.000
Xaysomboune	0.715 [0.49, 1.05]	.087	0.632 [0.34, 1.18]	.152
Round
LSIS-I (2011/2012)^a
LSIS-II (2017)	1.629 [1.50, 1.76]	.000	3.521 [3.23, 3.84]	.000
Observation	22 786		22 782

Adjusted odds ratio (aOR) is reported.

Abbreviations: aOR, adjusted odds ratio; CI, confidence interval; LSIS, Lao Social Indicator Surveys.

Reference group.

Discussion

This study investigated the effects of basic drinking water and sanitation facilities on child undernutrition and diarrhea in Laos by exploiting LSIS-I (2011/2012) and LSIS-II (2017). We confirmed that children’s access to basic drinking water and sanitation at home, after controlling for potential confounders, had significant effects on reducing their likelihood of being undernourished and having diarrhea. There are three points to be discussed.

First, the favorable effects of basic drinking water and sanitation facilities on child nutrition and diarrhea in Laos adds new findings to the literature on the effectiveness of WASH in low- and middle-income countries (LMICs). Despite the importance of WASH in child nutrition and health, results from previous empirical studies in LMICs were mixed.^18
-23 Experimental studies using randomized controlled trials (RCTs) have shown minimal effects of WASH. For instance, providing safe drinking water, sanitation, and handwashing interventions reduced the incidence of diarrhea in children, but single treatment of drinking water did not reduce diarrhea in rural Bangladesh.²³ Individual interventions of drinking water, sanitation, and handwashing, as well as their combination, had no effect on linear child growth in Bangladesh, Kenya, and Zimbabwe.^23
-25 In contrast, several observational studies found more optimistic results on the associations between WASH and improved child health and nutrition. For instance, a study that analyzed four rounds of the Philippines National Demographic and Health Survey (DHS) found that the prevalence of child diarrhea was lower in households with access to piped water and those with flush toilets than in their counterparts.²⁶ Another observational study that analyzed multiple DHS data sets at the subnational region level in 59 countries found that access to piped water in their dwellings predicted reductions in child stunting, and access to sanitation was associated with reduced diarrhea prevalence and child mortality.²⁷

Second, we analyzed the interaction effect between drinking water and sanitation on child nutrition and diarrhea. The regression results showed that the interaction term between drinking water and sanitation was not significant in predicting childhood nutrition and diarrhea. The insignificance of the interaction on childhood diarrhea is consistent with a study that analyzed 42,284 children from four rounds of DHS in Ethiopia.²⁸ We found that access to basic drinking water, even in the absence of sanitation, was as effective in reducing child undernutrition and diarrhea as when sanitation was present. However, access to basic sanitation did not significantly reduce stunting and diarrhea unless basic drinking water was also available. These findings suggest that access to basic drinking water at home effectively improves child nutrition, but sanitation is effective in reducing stunting and diarrhea only when basic drinking water is also accessible at home.

Third, we confirmed significant socio-economic disparities in children’s access to basic drinking water and sanitation in Laos, particularly in relation to mothers’ educational attainment, ethnicity, and household wealth. To ensure the health and well-being of all people in Laos, the ninth National Socio-Economic Development Plan (NSEDP) primarily focuses on improving WASH and preventing diseases. Its WASH-related targets include increasing the percentage of basic drinking water from 83.9% in 2017 to 95% in 2025 and that of sanitation from 73.8% in 2017 to 85% in 2025.²⁹ As the ninth NSEDP emphasizes the importance of achieving national development goals while ensuring equitable advancements, policymakers should prioritize eliminating disparities in children’s access to basic WASH services in Laos.

Our study is not without limitations. The direction of causality from basic drinking water and sanitation to child nutrition and diarrhea was not fully ascertained because of the nature of the cross-sectional data. The causes of child undernutrition and diarrhea transmission are multifactorial and interrelated, spanning biological, socio-economic, and environmental aspects.²² Further investigations are required to clarify this point. For example, conducting RCTs is desirable to examine the effects of WASH interventions on children’s nutrition and diarrhea. Nevertheless, the implementation of RCTs requires significant expenditure, time, effort, and ethical considerations. Therefore, a more practical approach might be to collaborate with international organizations or government aid agencies to carry out prospective evaluation studies assessing the impact of the WASH projects they implement. For instance, a RCT-based study was conducted in Laos to evaluate the WASH in Schools (WinS) projects initiated by UNICEF.³⁰ Despite these limitations, our findings suggest a strong association between children’s access to drinking water and sanitation at home and improved health outcomes. . Thus, our results underscore the importance of WASH in ehnancing children’s health.

Conclusion

We examined the impact of drinking water and sanitation on nutrition and diarrhea among children in Laos. The findings showed that access to basic drinking water was associated with a reduced likelihood of undernutrition, and access to basic sanitation was effective in reducing diarrhea in addition to undernutrition. Specifically, when children had access to basic drinking water, the odds of them being stunted, underweight, and wasted decreased by 0.138, 0.099, and 0.164, respectively, after controlling for potential confounders. Regarding childhood diarrhea, supplying basic sanitation at home can potentially decrease the odds of the child having diarrhea by 0.138. These favorable effects of drinking water and sanitation highlight the importance of expanding WASH services to enhance child health and achieve health-related SDGs in Laos, where WASH coverage still remains low. As this research is the first attempt to analyze the relationship between WASH and child health using nationally representative cross-sectional data, it offers valuable insights for future studies.

Supplemental Material

sj-docx-1-aph-10.1177_10105395231204797 – Supplemental material for Effect of Drinking Water and Sanitation on Child Undernutrition and Diarrhea in Lao PDR

Supplemental material, sj-docx-1-aph-10.1177_10105395231204797 for Effect of Drinking Water and Sanitation on Child Undernutrition and Diarrhea in Lao PDR by Yusuke Kamiya and Takaaki Kishida in Asia Pacific Journal of Public Health

Footnotes

Acknowledgements

The authors would like to thank the participants to the LSIS for their cooperation.

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This study was supported by the Research Institute for Social Sciences, Ryukoku University. The content of this study is solely the responsibility of the authors.

ORCID iD

Yusuke Kamiya

Supplemental Material

Supplemental material for this article is available online.

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