Prevalence and determinants of under-five mortality (U5M) in low-and lower -middle-income countries: Evidence from recent demographic and health surveys.

OBJECTIVES: Under-five mortality (U5M) remains a major global challenge, particularly in low-and lower-middle- income countries (LLMICs) where healthcare disparities are prevalent. This study evaluates the prevalence of U5M and examines the relative importance of its associated factors across 32 LLMICs. METHODS: Data from the Demographic and Health Survey (2011-2024) were used for analysis. A total of 266,333 children under five years of age were included to assess the association of 20 factors at both individual and community levels with U5M. The chi-square test and multivariate logistic regression model were applied to determine the association of these factors with U5M. RESULTS: Among the children aged 0-59 months, the prevalence of U5M was 40.5 per 1,000 (95% CI: 39.8-41.2). In the pooled sample, at the individual level, family member (>7) was the strongest factor associated with U5M (adjusted odds ratio (AOR):1.27; 95% CI:1.22-1.33, p < 0.001), followed by maternal age ≥ 35 years (AOR: 1.25; 95% CI:1.20-1.30, p < 0.001), being a female child (AOR:1.19; 95% CI:1.15-1.24, p < 0.001), and maternal unemployment (AOR:1.10; 95% CI:1.05-1.14, p < 0.001). At the community level, high maternal illiteracy (AOR:1.52; 95% CI:1.35-1.70, p < 0.001) was the most significant factor, followed by rural residence (AOR:1.26; 95% CI:1.15-1.38, p < 0.001), high paternal illiteracy (AOR:1.20; 95% CI:1.10-1.30, p < 0.001), and high maternal unemployment (AOR: 1.10; 95% CI:1.02-1.20, p < 0.001). Furthermore, large family members at individual levels and high maternal illiteracy at the community level consistently rank among the top two strongest factors across most countries, with a few exceptions. CONCLUSIONS: In LLMICs, U5M remains high, strongly associated with large family size and high maternal illiteracy. Governments and non-governmental organizations should promote maternal education and contraception use to facilitate birth spacing and family planning, while tailoring interventions to country-specific contexts.