Prevalence of Overweight/Obesity Among Under-Five Children in Lower Middle-Income Countries and Assessment of the Reported Associated Factors: A Systematic Review and Meta-Analysis.

Background: Overweight/obesity among children under five is a growing global concern, especially in low- and middle-income countries (LMICs), yet consolidated evidence of this burden remains limited, which is crucial to target interventions. This review synthesises data from community-based studies to estimate the overall and individual pooled prevalences of overweight/obesity in this population and explores the factors associated.

Methodology: PubMed, Scopus and EMBASE were searched and screened for eligible studies published between April 2014 and 2024 individually by two researchers. Quality assessment of the eligible studies was conducted using the Joanna Briggs Institute (JBI) tool. Data regarding the prevalence of overweight, obesity and their associated factors, including maternal education, area of residence, maternal body weight, household incomes and breastfeeding practices, as reported in these included studies, were extracted. A random-effect model was used for the meta-analysis, and heterogeneity was evaluated using I² statistics. Sources of heterogeneity were explored through subgroup analyses comparing effect sizes across categories of geographic regions, overweight/obesity measurement guidelines, sample sizes and publication years. Meta-regression assessed the relationship between these variables and the pooled estimates.

Results: Of the 13 734 studies screened, 21 were eligible for inclusion. The pooled prevalence of overweight/obesity among the under-five children in LMICs was 8.57% (95% confidence interval (CI) 5.24-12.63, I² 100% at p value < 0.01) with significant heterogeneity. Overnutrition prevalence increased from 7.43% during the 5 years of 2014-2018 to 9.12% during 2019-2023. The pooled prevalence of overweight/obesity varied significantly across geography, with the highest prevalence in the African region (17%) and the lowest in the Southeast Asian region (3.41%). Across the four studies that reported maternal education, children of mothers with secondary school education or higher had increased odds of having overweight/obesity [Odds Ratio (OR) (95% CI): 1.51 (1.21-1.88)]. Prevalence estimates also differed significantly by gender, with 6.89% for under-five boys and 4.75% for girls [OR (95% CI): 1.48 (1.08-2.04)]. Although individual studies reported significant associations with other factors such as area of residence, maternal body weight, income status and breastfeeding practices, a meta-analysis could not be performed due to heterogeneity.

Conclusion: Trends in childhood overnutrition in LMICs are concerning, with overall prevalence approaching estimates of those reported in a few high-income nations. Geographic variability, gender disparity and association with maternal education emphasise the need for region-specific policies, focusing on community engagement and awareness towards rising overnutrition.