Mondal, Shuvagato2026-02-262026-02-26https://hdl.handle.net/1885/733806599Bangladesh, among the world's most climate-vulnerable nations, faces increasing challenges to ensure food security and universal access to water, sanitation and hygiene (WASH) facilities. This doctoral research investigates the dual burden of household food insecurity and inadequate WASH access and their combined impacts on child and maternal nutritional outcomes in climate-sensitive coastal regions of Bangladesh. Using a multidimensional framework, this study aimed to identify socioeconomic and demographic determinants of food insecurity and WASH access, measure prevalence and examine their combined effects on nutritional health among disadvantaged coastal populations. The study adopted a mixed-methods design, integrating secondary and primary data analyses. Secondary data from Bangladesh Demographic and Health Survey 2017- 18 were analysed to explore the links between socioeconomic inequalities, sanitation and childhood malnutrition. A cross-sectional household survey using a three-stage cluster sampling strategy recruited 471 mother-child pairs for primary data. Quantitative analyses, including multivariable logistic regression and structural equation modelling (SEM), identified individual, household, environmental-level factors, and assessed the dual burden of food insecurity and inadequate WASH access on undernutrition. In addition, qualitative insights from focus group discussions and key informant interviews explored community perspectives, underlying drivers, consequences, self-efficacy and policy implications regarding food and WASH insecurity. A thematic content analysis approach revealed deeper contextual insights into lived experiences and sociocultural factors shaping vulnerability, informing evidence-based, community-focused and context-specific interventions. In coastal Bangladesh, prevalence of child stunting (31.4%) and wasting (8.5%) exceeded national estimates, influenced by age, maternal education, household wealth, sanitation, child morbidity and maternal undernutrition. Food insecurity affected nearly 29% of households, with a majority lacking at least one basic WASH service. Lower chance of experiencing food insecurity was in households with younger head (40 years or less) [Adjusted Odds Ratio (AOR): 0.42] compared to older group, having educated mothers (AOR: 0.22) compared to uneducated and higher monthly income (AOR: 0.09) compared to lower income. WASH access was linked to household size, wealth, location, head's occupation and education. Poorer households had significantly lower odds (AOR: 0.24) of safe water access than the wealthiest, while access was higher in southeastern coastal part (AOR: 1.67) than those in southwest. Larger households (AOR: 0.61) and fishermen headed (AOR: 0.30) were less likely to have improved sanitation access than smaller and headed by service-holders. Lower adults' educational attainment was associated with reduced access to basic hygiene and combined WASH services. Among coastal communities, 54.4% of children were stunted, 25.2% underweight and 9.4% wasted, with 61.6% exhibiting at least one anthropometric failure. Among mothers, one-third were obese and 34.5% anaemic. Child malnutrition was strongly associated with younger age, lower household wealth, food insecurity, poor water and sanitation access, maternal underweight and recent occurrence of diarrhea. SEM demonstrated that combined effect of food security and WASH access had a larger positive effect on both child's and maternal better nutritional outcomes, with standardised coefficient values of 0.50 and 0.68, respectively. This thesis highlights the urgent need for integrated, multisectoral, and context specific policy interventions to combat malnutrition in coastal Bangladesh. It provides a robust foundation of evidence to support equity-focused health and nutrition strategies that tackle the interconnected issues of food insecurity and inadequate WASH access among geographically vulnerable communities.en-AU202610.25911/MBGQ-5E31