Vitamin D deficiency in girls from South Brazil: a cross-sectional study on prevalence and association with vitamin D receptor gene variants

Cross-sectional study including 234 apparently healthy girls aged 7 to 18？years. Height and weight were measured for calculation of body mass index (BMI) percentiles for age. Plasma levels of 25-hydroxyvitamin D [25(OH)D] were assessed. Participants were genotyped for ApaI (rs7975232), TaqI (rs731236), and BsmI (rs1544410) SNPs.The median and interquartile range (25-75%) of BMI percentile was 62.0 (33.3 – 84.9). The frequency of overweight/obesity was 24.9%. Circulating levels of 25(OH)D (≥ 30？ng/mL) were adequate in 9.4%; insufficient in 54.3% (20–29？ng/mL); and deficient in 36.3% (< 20？ng/mL). Genotype frequencies were GG？=？47.0%, GA？=？41.5%, and AA？=？11.5% for BsmI; GG？=？16.7%, GT？=？52.6%, and TT？=？30.8% for ApaI; TT？=？46.2%, TC？=？44.9% and CC？=？9.0% for TaqI. Genotypes with no gene variance (ancestral wild genotype) of BsmI (GG vs. GA？+？AA, two-tailed Student’s？t-test p？<？0.001), ApaI (GG vs. GT？+？TT, two-tailed Student’s？t-test p？=？0.031) and TaqI (TT vs. TC？+？CC, two-tailed Student’s？t-test p？=？0.005) SNPs and the GGT haplotype (two-tailed Student’s？t-test p？=？0.036) were significantly associated with lower 25(OH)D levels.25-hydroxyvitamin D deficiency and insufficiency were highly prevalent in this sample. The BsmI, ApaI and TaqI wild variants of the VDR gene, as well as the GGT haplotype, were associated with lower vitamin D levels, suggesting that VDR gene polymorphisms could be linked to higher susceptibility to vitamin D deficiency in a sub-population of children and adolescents.Vitamin D is mainly recognized for its effects on bone metabolism and for being an important determinant of growth and body development during childhood and adolescence. However, a high prevalence of vitamin D deficiency has been observed in several pediatric and adolescent populations [1-3] in association with overweight/obesity, blood pressure and glucose metabolism [4-6]. While these studies report no gender-related differences in vitamin D levels, recent evidence shows that gi