Hypovitaminosis D in Migrant Children in Switzerland: a Retrospective Study

Abstract Cholecalciferol (vitamin D3) is essentially known for its part in the phospho-calcic metabolism and associated pathologies, such as rickets. In Switzerland, 40 to 50% of children are vitamin D deficient. Due to skin colour, poor nutrition, living condition and cultural practices, migrant population is particularly at risk. Our aim is to attest the vitamin D status of the children arriving in Switzerland and compare the cost-effectiveness of two supplementation strategies. We retrospectively assessed 528 children’s vitamin D status and parathyroid hormone, phosphates and calcium levels between 2015 and 2018 by electrochemiluminescence and spectrophotometry. Cholecalciferol was considered insufficient under 50 nmol/L and severely deficient below 25 nmol/L. Supplementation strategies’ costs were based on local prices. Seventy-three percent of children showed hypovitaminosis D and 28% had a severe deficit. Highest prevalence of deficit was found in children from Eastern Mediterranean (80%) and African regions (75%). Severe deficit was highest in the South East Asian (39%) and Eastern Mediterranean regions (33%) and higher in females than males. Deficit was predominant and more severe in winter. Hypovitaminosis increased with age. 0.4% of children presented with biological rickets. The most cost-effective supplementation strategy was to systematically supplement all children at arrival and in winter, reducing costs by 25% compared to vitamin D level-based supplementation. Conclusion: A majority of migrant children presented with hypovitaminosis D. They must be supplemented to prevent complications. A cost-effective strategy could be to supplement all children at arrival and during wintertime without systematic vitamin D level check.