Extreme rainfall and anaemia among children under five in 46 low- and middle-income countries

BACKGROUND: Childhood anaemia remains a major public health challenge in low- and middle-income countries (LMICs). While extreme rainfall has been linked to child growth, its impact on childhood anaemia has not been well characterised. METHODS: Our study used data from the Demographic and Health Survey programme conducted between 2000-2022 across 46 LMICs, comprising 373 901 children aged 6-59 months. Generalised linear models estimated ORs for childhood anaemia associated with extreme rainfall events during maternal pregnancy and the 3 months preceding the survey. We further quantified the burden of childhood anaemia attributable to extreme rainfall. RESULTS: The overall prevalence of childhood anaemia was 61.9%. Among 373 901 children, 69 481 (18.6%) experienced at least one extreme rainfall event with a 5-year return period during pregnancy, and 28 776 (7.7%) were exposed within the 3 months preceding the survey. Maternal exposure during pregnancy was associated with a modest increase in anaemia risk (OR: 1.025; 95% CI 1.007 to 1.044), whereas exposure during the 3 months prior to the survey showed a greater magnitude of association (OR: 1.137; 95% CI 1.107 to 1.168). Age-stratified analyses indicated that children aged under 2 years were more sensitive to maternal exposure, whereas those aged 2 years and older were more affected by rainfall exposure before the survey. Extreme rainfall was estimated to be responsible for approximately 5 million cases of childhood anaemia, with the highest absolute burden observed in sub-Saharan Africa. CONCLUSIONS: Childhood anaemia in LMICs is associated with extreme rainfall, with disproportionate impacts observed in sub-Saharan Africa. These findings underscore the need to integrate climate variability into strategies for anaemia prevention and child health protection.