Inadequate Vitamin D Levels and Associated Risk Factors Among Children Under Five Years in Southeast Asia: A Systematic Review and Meta-analysis

Vitamin D deficiency (VDD) and Vitamin D insufficiency (VDI) in children in Southeast Asia (SEA) pose significant public health concerns, impacting growth and non-skeletal health. This study aimed to (1) assess the prevalence of inadequate Vitamin D levels among children under five years in SEA and (2) identify associated risk factors. A meta-analysis was conducted, systematically reviewing articles from ProQuest, EBSCO, and PubMed (January 2013–October 2024). Inclusion criteria encompassed original, English-language, cross-sectional studies focusing on children under five years with documented serum 25(OH)D levels. Studies conducted outside SEA, lacking full text, addressing irrelevant topics, or containing insufficient data were excluded. Statistical analysis employed the DerSimonian and Laird random-effects model, with 95% CI calculated using the Clopper-Pearson method. A total of 13 cross-sectional studies from Thailand, Malaysia, Indonesia, Philippines, Cambodia, and Vietnam were included, with a combined sample size of 4,321 subjects. The prevalence of VDD among children under five years in SEA was 35% (95% CI, 24%-45%; I2, 98.15%), and VDI was found in 34% (25%-44%; I2, 89.67%). The mean serum vitamin D level (nmol/L) was 57.97 (48.83–67.10; I2, 99.99%). Maternal VDD or VDI was found to be associated with inadequate Vitamin D levels among children under five years in SEA, with a Pooled Odds Ratio of 4.25 (95% CI: 1.76–6.74; I2 =87.57%). This study underscores the high prevalence of inadequate Vitamin D levels among children under five in SEA, highlighting the urgent need for targeted public health interventions to mitigate this growing concern.