Abstract
Abstract
Background
Lead is a cumulative environmental toxicant for which no safe level of exposure has been identified, and pregnant women and their fetuses are particularly vulnerable because lead readily crosses the placenta and can be mobilised from maternal bone stores. Bangladesh conducted its first nationally representative blood lead testing among pregnant women through the 2025 Multiple Indicator Cluster Survey (MICS), but a detailed, multi-domain analysis of the determinants of elevated blood lead level (BLL) among this population has not yet been reported.
Methods
We conducted a secondary cross-sectional analysis of 1,928 pregnant women aged 15– 49 years with complete data from the women’s dataset of Bangladesh MICS 2025. Elevated BLL was defined as ≥5 μg/dL. Survey-weighted logistic regression was used to estimate unadjusted and adjusted odds ratios (aOR) for co-exposure to arsenic, cadmium and mercury and sociodemographic and socioeconomic covariates. Slope Index of Inequality (SII) as well as Relative Index of Inequality (RII) were used to quantify wealth-related inequality. Population attributable fractions (PAF) were estimated for three counterfactual scenarios, and adaptive least absolute shrinkage and selection operator (LASSO) regression was used as a sensitivity analysis.
Results
Elevated BLL was present among 6.2% of participants. In the adjusted model, a 2-fold rise in blood cadmium was associated with higher odds of elevated BLL (aOR: 1.54; 95% CI: 1.21–1.96), whereas a 2-fold rise in blood mercury (aOR: 0.63; 95% CI: 0.48–0.83), rural residence (aOR: 0.55; 95% CI: 0.32–0.94), secondary education (aOR: 0.49; 95% CI: 0.28–0.85) and post-secondary education (aOR: 0.22; 95% CI: 0.11–0.46) were associated with lower odds. Belonging to progressively wealthier quintiles was associated with markedly higher odds, BLL rising to an aOR of 10.32 (95% CI: 4.41–24.15) for the richest versus poorest quintile. The RII was 8.59 (95% CI: 4.24–17.40) and the SII was 0.159 (95% CI: 0.101–0.218), indicating a substantial pro-rich gradient in elevated BLL. Counterfactual scenarios suggested that shifting the population to secondary-level education could reduce the prevalence of elevated BLL by 52.9% (95% CI: 20.6–72.0) and shifting to rural residence by 24.3% (95% CI: 1.4–41.9). Adaptive LASSO variable selection produced estimates consistent in direction and magnitude with the fully adjusted model.
Conclusion
In this national sample, approximately one out of every 16 pregnant women had blood lead levels that met or exceeded the action threshold set by the World Health Organization, with this issue being particularly prevalent among wealthier, urban, and less-educated women, and was compounded by co-exposure to cadmium. In Bangladesh, the typical pattern observed for maternal and child health indicators does not align with the inverse relationship found between household wealth and lead exposure. This suggests that the sources of exposure are not merely indicators of material poverty. Antenatal blood lead screening, source investigation, and equity-informed lead-reduction strategies that specifically reach wealthier and urban households are warranted.