LAUSR

Abstract Introduction Vitamin D is an essential prohormone in calcium and phosphorus homeostasis. Recent studies show a high frequency of insufficiency/deficiency of vitamin D in the general population worldwide. Our objective was to estimate the prevalence of circulating vitamin D [25(OH)D3] deficiency and insufficiency in children and examine the associated factors. Material and methods A total of 283 children, participants in the cohort INMA-Asturias, were studied. The 25(OH)D3 concentrations were quantified by high performance liquid chromatography. The prevalence of deficiency [25(OH)D3  Results The mean 25(OH)D3 was 20.1 ng/mL (range 2.7–49.8), with 8.8% ≥30 ng/mL, 38.5% from 20 to 20.9 ng/mL, and 52.7%  Conclusions There is a high prevalence of vitamin D deficiency/insufficiency in children at 4 years. Solar exposure might not be enough in our region. Healthy children should be encouraged to follow adequate outdoor activities with associated sun exposure. Due to the deficit of intake in childhood, recommendations are needed about a varied diet with vitamin D-containing foods in this age group, especially during the winter, and assessing the need of vitamin D supplementation in children at risk.