Transition in availability of improved sanitation facilities and its effect on diarrhoeal disease in India: evidence from longitudinal data

Background Poor sanitation, such as open defecation, is a major public health concern in India, causing diarrhoea and other infectious diseases. So far, few studies have linked poor sanitation with diarrhoea using longitudinal data. In this context, this study assesses the transition in availability of household sanitation facilities and its effect on diarrhoeal morbidity. Methods We used two waves of longitudinal data from the India Human Development Survey, conducted in 2004-2005 and 2011-2012, and based on 34 131 followed-up households using a two-stage stratified random sampling method. In the first stage, multinomial logistic regression was used to assess socio-economic factors contributing to the transition in the availability of household sanitation facilities. In the second stage, multivariate linear regression was performed to examine the effect of the change in the availability of household sanitation facilities on the prevalence of diarrhoeal morbidity. All the analysis in this study was carried out by using Stata version 13 software. Results The findings reveal that the practice of open defecation was continued to be higher among lower socio-economic households than better-off socio-economic households in both 2004-2005 and 2011-2012. The proportion of household members who fell sick due to diarrhoea morbidity has decreased significantly (beta=-0.06, p<0.04) among households that switched from open defecation in 2004-2005 to improved sanitation facilities in 2011-12, compared to households that continued to practice open defecation in both periods (2004-2005 and 2011-2012). The share of household members who fell sick due to diarrhoeal morbidity was significantly lower (beta=-0.09, p<0.001) among the households who adopted improved toilet facilities in both periods (2004-2005 and 2011-2012) as compared with the households who continued to defecate openly in both periods, net of other covariates. Conclusions Our findings show that there is a need to strengthen existing policies focusing on lower socio-economic groups to improve sanitation and eliminate its related diseases. In particular, the ongoing 'Clean India Mission' should play a critical role in promoting sanitation for all.