25-hydroxyvitamin D is differently associated with calcium intakes of Northern, Central and Southern European adolescents: results from the HELENA study

Abstract

European (EU) adolescents exhibit a higher prevalence of vitamin D (VitD) deficiency than other age groups. The efficiency of sunlight exposure to increase 25(OH)D concentrations depends on a variety of factors, including diet. Nevertheless, the relationship between calcium and vitamin D (VitD) intake and 25 (OH)D concentrations have not been previously studied among adolescents living in different EU countries and consequently in different latitudes. Therefore, the aim of this study is to examine whether calcium and VitD intakes are differently associated with 25(OH)D in North, Central and South EU adolescents. 178 adolescents from Northern EU countries, 251 from Central EU countries and 212 from Southern EU countries aged 12.5-17.5 years were included in the current analyses. Mixed model linear regression analyses stratified by geographical location were used to verify associations between calcium and VitD intakes and 25(OH)D concentrations. Age, Tanner stage, seasonality, energy intake and supplement use were entered as covariates. Only calcium intakes of Central EU adolescents were positively associated with 25(OH)D (α= 0.005; CI 0.007, 0.028). Further longitudinal studies should confirm these observations, as this could be important for future public health interventions aiming to increase 25(OH)D concentrations among adolescents.