Socioeconomic determinants of elevated blood lead among children aged 12-59 months in Bangladesh: a nationally representative survey

Background: Childhood lead exposure is a major global health concern. The 2025 Bangladesh Multiple Indicator Cluster Survey (MICS7) measured blood lead in a nationally representative sample of children aged 12-59 months for the first time. Preliminary reports suggested elevated blood lead was more common in wealthier urban households, contrary to the usual assumption. Methods: We analysed 10,622 children with a valid blood lead result (10,458 with complete covariate data for regression models). Elevated blood lead was defined as >=5 ug/dL. Prevalences are survey-weighted with design-based confidence intervals. Associations were estimated with survey-weighted logistic regression using stratified-cluster (Taylor-linearised) variance, and checked with a stratified bootstrap of primary sampling units and Benjamini-Hochberg false-discovery-rate control. Sensitivity analyses varied the outcome definition, the sample, and the weighting. Results: Survey-weighted prevalence of elevated blood lead was 38.5% (95% confidence interval [CI] 37.2-39.9%). Prevalence rose monotonically from 30.2% in the poorest to 51.9% in the richest wealth quintile. In the fully adjusted model, each wealth quintile was associated with 23% higher odds (adjusted odds ratio [AOR] 1.23, 95% CI 1.16-1.30), each level of maternal education with 20% lower odds (AOR 0.80, 95% CI 0.76-0.84), and urban residence with 37% higher odds (AOR 1.37, 95% CI 1.18-1.59). Household crowding was associated with higher odds (AOR 1.17 per person per room, 95% CI 1.10-1.24). The wealth-education interaction had AOR 0.95 (95% CI 0.92-0.98). In an exploratory contrast, weighted prevalence was 76.2% among children in the richest quintile with mothers having at most primary education versus 19.5% among those in the poorest quintile with mothers having higher secondary or tertiary education (prevalence ratio 3.9, 95% CI 2.6-6.0). Adjusted odds relative to Barishal ranged from 0.39 in Rajshahi to 3.29 in Dhaka. Conclusions: In this cross-sectional survey, elevated blood lead was more prevalent among wealthier and urban households and among children of less educated mothers, with large geographic variation. Lead prevention and source-identification efforts should therefore not be restricted to poor communities; prevalence remained high even in the poorest quintile. Interpretation is limited by substantial missing blood lead results and coding uncertainty.