Equity in access to safely managed sanitation and prevalence of diarrheal diseases in Bangladesh: a national and sub-national analysis.

BACKGROUND: In Bangladesh, safely managed sanitation (SMS) coverage is low, and diarrheal disease is a significant health problem. This study estimated the inequality in access to SMS facilities at the national and sub-national levels and assessed the prevalence of diarrheal diseases in connection with these improved facilities. METHODS: Data were extracted from the Bangladesh Demographic and Health Survey, conducted during 2017-2018. SMS was defined as using an improved sanitation facility, which designed to hygienically separate excreta from human contact and include the use of a flush toilet connected to piped sewer system, septic tank, ventilated improved pit latrine, pit latrine with a slab, and composting toilet. The slope index of inequality (SII) and multi-level regression models were used for inequality and risk factors of SMS respectively. RESULTS: The national coverage of SMS was 44.0% (45.3% and 43.5% in urban and rural areas, respectively). At the sub-national level, the lowest and highest coverage of SMS was observed in Mymensingh (32.9%) and Chittagong (54.1%) divisions, respectively. The national level SII indicated that wealthy households had access to higher SMS by 60.8 percentage points than poor households. Additionally, greater inequality was observed in rural areas, which was 71.9 percentage points higher in the richest households than in the poorest households. The coverage gap between the rich and poor was highest in the Sylhet division (85.3 percentage points higher in rich than in poor) and lowest in Dhaka (34.9 percentage points). Old and highly educated household heads and richest households had better access to higher levels of adequate sanitation. After adjusting for confounding variables, the prevalence of diarrheal disease was 14.0% lower in the SMS user group than in their counterparts. CONCLUSION: Substantial inequalities in access to SMS exist at both national and sub-national levels of Bangladesh, with the prevalence of diarrhea being lower among SMS users. These findings may help to prioritize resources for reducing inequality and expanding the coverage of improved sanitation in Bangladesh.