Vitamin D levels in an area of low solar radiation in the north of the Iberian Peninsula

Introduction: vitamin D deficiency is a cause of concern in Europe, especially in latitudes above the 40° N parallel, and several clinical factors are involved. Most prevalence studies in the paediatric population in Spain have been carried out in latitudes with high sunlight exposure. Materials and Methods: cross-sectional descriptive study in two periods (summer and winter seasons) in healthy children aged 2 to 14 years between July 15, 2013 and April 15, 2016, through data collection and blood analysis (calcifediol, calcium, phosphorus) in a total of 603 children residing in La Garrotxa (Girona) (latitude 42° N), an area in Catalonia with low sun exposure. We calculated prevalences and performed a multivariable regression analysis to determine the impact of different clinical variables. Results: 31.86% of children had levels of vitamin D below 20 ng/mL that increased to 52.87% in winter. Ethnicity, phototype and season of the year accounted for 53.2% of the observed variation. Conclusions: children in an area of low solar radiation of Spain had a high prevalence of hypovitaminosis D, especially in the winter, in those with dark skin phototypes and in certain ethnic groups.