<p>Variance inflation factor summary.</p>

Mortality following severe acute malnutrition (SAM) remains high in Africa. Some children with SAM have altered immune responses and impaired neurodevelopment; however, whether vitamin D deficiency contributes to these poor outcomes remains unclear. We conducted a cross-sectional analysis of circulating 25-hydroxyvitamin D [25(OH)D] concentrations at hospital discharge (25(OH)D) in 442 children aged 0–59 months with SAM at one hospital in Lusaka, Zambia, and two hospitals in Harare, Zimbabwe. Also, we investigated the relationship between 25(OH)D concentrations and host factors. In 442 children, plasma 25(OH)D concentrations were measured using ELISA. Vitamin D deficiency was identified in 33/442 (7.5%; 95% CI: 5.2–10.3) children, all of whom were from Zimbabwe. A multivariable regression model that included age, sex, HIV status, season, oedema, cerebral palsy, and country demonstrated significantly higher 25(OH)D levels among children aged 6–11 months (adjusted (adj) ratio; 1.3; 95% CI: 1.1, 1.6; P = 0.003), 12–23 months (adj ratio; 1.5; 95% CI: 1.3, 1.8; P < 0.001), and 24–59 months (adj ratio; 1.5; 95% CI: 1.3, 1.8; P < 0.001) compared with those <6 months. Sampling during the cool season (adj ratio; 1.2; 95% CI: 1.1, 1.3; P = 0.002), absence of cerebral palsy (adj ratio; 1.2; 95% CI: 1.1, 1.4; P = 0.002) and residence in Zambia (adj ratio; 1.2; 95% CI: 1.1, 1.2; P < 0.001) were associated with higher concentrations of 25(OH)D, even after excluding children <6 months. These findings indicate that vitamin D status among children with SAM is significantly influenced by age, seasonality, cerebral palsy, and geographical location. To facilitate management and improve clinical outcomes in these children, we recommend further investigation into whether the current vitamin D content in ready-to-use therapeutic foods is sufficient for all children and whether additional supplementation improves clinical outcomes, especially in high-risk groups. If deficiency is present, we recommend that children be managed in accordance with local guidelines and policies.