Socio-demographic and environmental factors associated with diarrhoeal disease among children under five in India

This study used secondary data collected from the fourth round of the National Family Health Survey (NFHS-4), conducted in 2015–16. A cross-sectional design was adopted in this study.

All living under-five children (n = 247,743) who participated in the NFHS-4 were enrolled in the study. The NFHS-4 is a nationally representative large-scale sample survey carried out across all the states and union territories of India. The samples were selected using a two-stage stratified sampling design. In the first stage, the clusters were selected using the method of probability proportional to size. In the second stage, complete household mapping and listing have been done in the selected clusters and 22 households were randomly selected from each cluster. The sampling frame used in this survey was the 2011 Indian Population and Housing Census. A detailed description of the sampling design and survey procedure is provided in the NFHS-4 national report [5].

The outcome variable of this study is diarrhoeal disease in children under five. Diarrhoea is defined as having three or more loose or watery stools in 24 h, as reported by the mother/caregiver in the past 2 weeks preceding the survey.

Socio-demographic and environmental characteristics were included for explanatory variables in this study. The operational definition and coding of variables are included in Table 1. Socio-demographic characteristics include place of residence (rural and urban), caste (scheduled castes/scheduled tribes, other backward classes, and others), religion (Hindu, Muslim, and others), maternal education (illiterate/primary and secondary/above) father’s education (illiterate/primary and secondary/above), maternal age (15–24, 25–34, and 35–49 years), maternal body mass index [BMI] (underweight, normal, and overweight/obese), access to mass media (no and yes), household size (< 6 and 6+), wealth quintile (poorest, poorer, middle, richer, and richest), region (north, central, east, northeast, west, and south), age of the child (0–11, 12–23, 24–35, 36–47, and 48–59 months), sex of child (male and female), birth order (1, 1–3, and 4+) and birth weight (< 2.5 kg [low birth weight] and ≥ 2.5 kg [normal]).

Environmental characteristics include the availability of toilet facility, sources of drinking water, child stool disposal, and main floor and roof materials of the household. Household toilet facility was a dichotomous variable, classified as households having a toilet facility and households without a toilet facility. Any improved, unimproved, and shared latrine facility (flush or pit) were considered as households having a toilet facility, otherwise households using open defecation. Sources of drinking water were categorized as improved and unimproved sources. Improved sources of drinking water are protected from outside contamination, particularly from fecal matter [22]. Improved sources include piped water, public taps, standpipes, tube wells and boreholes, protected dug wells and springs, rainwater, and community reverse osmosis plants, while unimproved sources comprise unprotected dug well, unprotected spring, tanker/cart with a small tank, surface water, and bottled water. Child stool disposal was grouped into safe and unsafe disposal. Children’s stool was considered to be safely disposed, if a child used a toilet or latrine, or flushed into a toilet, or it was buried [5]. The main floor materials of the houses were categorized as dirt (e.g., mud/clay/earth, sand, and dung) and non-dirt (e.g., raw wood planks, palm, bamboo, brick, stone, parquet or polished wood, vinyl or asphalt, ceramic tiles, cement, carpet and polished stone/marble/granite). Likewise, the main roof materials of the dwelling unit were grouped into thatch (e.g., thatch/palm leaf, mud, plastic/polythene, rustic mat, palm/bamboo, timber, etc.) and metal/concrete (e.g., metal, wood, asbestos sheets, cement/concrete, tiles, slates, burnt bricks, etc.).

Descriptive statistics were carried out to understand the distribution of socio-demographic and environmental characteristics for the study sample. The prevalence of diarrhoeal disease was estimated by selected explanatory variables. Pearson’s chi-square test was used and variables with p < 0.05 were included for further analysis. The sample weight was used for the estimation of percentage distribution. Bivariate and multivariate logistic regression models were employed to assess the socio-demographic and environmental factors associated with diarrhoea in children under five. The regression results are presented by unadjusted and adjusted odds ratio (OR) with 95% confidence interval (CI) and the results were considered to be statistically significant at p < 0.05. All the statistical analyses were performed using STATA version 14.0 (StataCorp LP, College Station, TX, USA).

A total of 247,743 living children aged 0–59 months were included in the analysis. The majority of children who lived in rural areas (71.6%), affiliated to Hindu (78.6%), belonged to poor families (24.9% in the poorest wealth quintile and 21.8% in the poorer wealth quintile) and resided in the central and east regions of the country. About 43.5% of mothers had below the secondary level of education, while the corresponding figure for fathers was 31.6%. About 57.7% of mothers were in the age range of 25–34 years and one-fourth (24.8%) of them were underweight. Over one-third of mothers (34.3%) had no exposure to mass media. Respondents were almost equally distributed in all age groups. Among total children, 52.1% were male, 47.5% were in the birth order of 2–3, and 17.7% of children had low birth weight (Table 2).

Around 46.5% of children living in the houses had no toilet facility. Only about 10% of children were drinking water from unimproved sources. About two-thirds (65.9%) of parents reported that their practice for child stool disposal was not safe. About 43.2% of children living in houses were made of dirt floor materials, and 14% of houses were made of thatch roof materials (Table 3).

The prevalence of diarrhoea was significantly higher in children living in rural areas as compared to those living in urban (9.6 vs. 8.2%) (p = 0.001). Childhood diarrhoea was common among scheduled caste (9.6%) and other backward class (9.6%) and Muslim children (9.9%). Maternal education was found to be significantly correlated with children’s diarrhoea occurrence (p < 0.001). However, father’s education was not significantly associated with child diarrhoea (p = 0.950). The occurrence of diarrhoea was substantially higher among those children whose mothers were in 15–24 years (10.7%), underweight (10.1%), and had no access to mass media (10.3%). Childhood diarrhoea was also higher in children from the poorest households (10.2%) and those from the central region of the country (13.1%). Furthermore, the prevalence of diarrhoeal disease was common among children aged 0–11 months (14.0%) and 12–23 months (13.4%), male children (9.5%), birth order above three (10.4%), and children with low birth weight (10.2%) (Table 4).

The prevalence of diarrhoea was found to be considerably higher in children of households who had no toilet facility compared to those whose households had a toilet facility (10.0 vs. 8.3%). The proportion of children with diarrhoea from households with improved drinking water sources was higher than those children whose households consumed unimproved sources (9.2 vs. 8.0%). The prevalence of diarrhoea was higher among households where child stool disposal practices were not safe (10.0%). The occurrence of diarrhoea was substantially higher in children living in houses having dirt floor (10.3%) and thatch roof materials (10.4%) (Table 5).

In bivariate analysis, it is found that all the selected socio-demographic factors were significantly associated with children’s diarrhoea in the past 2 weeks. Multivariate analysis of this study revealed that children living in rural areas had 5% higher likelihood of diarrhoeal disease (aOR: 1.05; 95% CI: 1.01, 1.09) as compared to living in urban. Children belonged to the scheduled tribe (aOR: 0.83; 95% CI: 0.79, 0.89) and other castes (aOR: 0.92; 95% CI: 0.88, 0.97) were less likely to develop diarrhoea as compared to scheduled caste children. The likelihood of childhood diarrhoea was 18% higher among Muslim children (aOR: 1.18; 95% CI: 1.13, 1.24) as compared to children from Hindu religion. Participants whose mothers had the secondary and above level of education were associated with 9% decreased odds of diarrhoea (cOR: 0.92; 95% CI: 0.88, 0.97) as compared to those mothers who had no formal education or had primary level of education in crude analysis. However, this association was not significant in the adjusted analysis.

Unadjusted analysis of this study also found that the likelihood of childhood diarrhoea decreased with an increase in maternal age. Children of mothers aged 25–34 years (cOR: 0.77; 95% CI: 0.75, 0.80) and 35–49 years (cOR: 0.73; 95% CI: 0.69, 0.77) were less likely to suffer from the diarrhoeal disease than those children of mothers aged 15–24 years. Maternal BMI also had a significant association with children’s diarrhoea occurrence in unadjusted analysis. Children of underweight women (cOR: 1.11; 95% CI: 1.08, 1.15) were 11% more likely and children of overweight/obese women (cOR: 0.87; 95% CI: 0.83, 0.91) were l3% less likely to develop diarrhoea as compared to children of mothers who had normal BMI. The results also revealed that access to mass media of women was found to be a protective factor against childhood diarrhoea. Children of women who had mass media exposure were associated with 18% decreased odds of diarrhoea (cOR: 0.82; 95% CI: 0.80, 0.95) than those women who were not exposed to mass media. Wealth status of the household was found to have a strong association with childhood diarrhoea. Children in the richest wealth quintile were 26% less likely to have diarrhoea as compared to those children in the poorest wealth quintile (cOR: 0.74; 95% CI: 0.71, 0.78). The occurrence of diarrhoea was also varied across geographical regions. After adjusting for socio-demographic and environmental characteristics, children from the central (aOR: 1.61; 95% CI: 1.52, 1.70) and west (aOR: 1.08; 95% CI: 1.01, 1.15) regions were more likely and children from the northeast (aOR: 0.49, 95% CI: 0.43, 0.56) and south (aOR: 0.80, 95% CI: 0.75, 0.85) regions were less likely to experience diarrhoea as compared to children from the north region of the country.

The risk of diarrhoea was decreased by 4–71% in children aged 12–23 months (aOR: 0.96; 95% CI: 0.92, 1.00), 24–35 months (aOR: 0.58; 95% CI: 0.55, 0.61), 36–47 months (aOR: 0.39; 95% CI: 0.37, 0.41) and 48–59 months (aOR: 0.29; 95% CI: 0.28, 0.31) as compared to those children aged 0–11 months. Female children were associated 8% decreased odds of diarrhoea (aOR: 0.92; 95% CI: 0.89, 0.95) than male children. Birth order was found to be positively related to diarrhoeal disease in children. The odds of diarrhoeal disease increased by 22% in fourth or higher birth order children (cOR: 1.22; 95% CI: 1.17, 1.27) as compared to first birth order children. Low birth weight also increased the risk of diarrhoea by 19% (cOR: 1.19; 95% CI: 1.15, 1.24) as compared to children with normal birth weight (Table 6).

Crude analysis demonstrated that children having a toilet facility in their houses had 18% less likely to have diarrhoeal diseases (cOR: 0.82; 95% CI: 0.80, 0.84) than those children who had no toilet facility in their houses. Surprisingly, children living in households having improved sources of drinking water were associated with higher odds of diarrhoea (cOR: 1.17; 95% CI: 1.12, 1.24) compared to those households having unimproved sources of drinking water. Child unsafe stool disposal was associated with an elevated risk of diarrhoea (aOR: 1.06; 95% CI: 1.02, 1.11) as compared to safe disposal of child stool. Children from households having dirt floor materials were associated with 8% higher likelihood of diarrhoea (aOR: 1.08; 95% CI: 1.03, 1.12) compared to those whose households had non-dirt floor materials. Similarly, children living in houses having thatch roof materials were 8% more likely to experience diarrhoeal disease (aOR: 1.08; 95% CI: 1.04, 1.13) than those children from houses with metal or concrete roof materials (Table 6).

The current study findings should be discussed in light of some limitations. First, causality cannot be assumed from this analysis due to the cross-sectional nature of data. Further research is needed using longitudinal data to examine the potential pathways for the occurrence of diarrhoea in children. Second, this study used self-reported retrospective information. Therefore, potential recall bias might have been introduced in this study [28]. Lastly, since the study used secondary data, it was not possible to include all important potential factors of diarrhoeal disease, particularly behavioral factors in the analysis due to the paucity of information in the dataset.

Besides the above limitations, this study provides comprehensive evidence on the socio-demographic and environmental factors associated with diarrhoeal disease in children under five using a large-scale demographic and health survey in India. The study used a large number of samples with nation-wide representation. Further, this study provides more evidence on factors that need to be targeted by public health interventions in an effort to further reduce the prevalence of diarrhoea in children.