RESUMO
OBJECTIVE: We aim to evaluate how vitamin D-containing supplements affect the vitamin D status of children 1-3 years old and to assess the variation of the vitamin D concentrations across different seasons. METHODS-MATERIAL: This retrospective study included a review of medical reports of 1035 patients (aged 1-3 years) who presented to our hospital between October 2011 and October 2013. The children were divided into 3 groups: Group 1: those supplemented with vitamin D3 (400 IU/day), Group 2: those supplemented with multivitamins, which included 200-400 IU/day of vitamin D2 or D3, and Group 3, the controls: those not supplemented with vitamin D. The groups were compared as to their biochemical findings and variation of vitamin D status with over four seasons. RESULTS: Gender distribution was not statistically different between the three groups (p=0.38). The children who had taken vitamin D-containing supplements had significantly higher vitamin D levels compared with the children who were given no vitamin D supplementation (p<0.001). Children with no vitamin D supplementation had significantly lower calcium and phosphorus levels compared with Groups 1 and 2. Vitamin D levels were affected by vitamin D supplementation (f=16.125, p<0.001) but not by season (f=0.699, p=0.650). CONCLUSION: The children aged 1-3 years who did not receive vitamin D-containing supplements had insufficient vitamin D and low levels of calcium and phosphorus. Vitamin D levels were affected by vitamin D supplementation but not by season.