25-Hydroxyvitamin D3 1-alpha-Hydroxylase25-Hydroxyvitamin D 2CalcifediolVitamin DVitamin D DeficiencyCholecalciferolHydroxycholecalciferolsErgocalciferolsDihydroxycholecalciferols24,25-Dihydroxyvitamin D 3Steroid HydroxylasesParathyroid HormoneCalcitriolVitamin D-Binding ProteinRicketsSunlightCholestanetriol 26-MonooxygenaseReceptors, CalcitriolSeasonsDietary SupplementsVitaminsPhosphorusCalcium, DietaryOsteomalaciaBone DensityCalciumHydroxylationCross-Sectional StudiesNutritional StatusSkin PigmentationBone and BonesCytochrome P-450 Enzyme SystemRisk FactorsLinear ModelsKidneyProspective StudiesBone Density Conservation AgentsBiological MarkersChromatography, High Pressure LiquidCase-Control StudiesFood, FortifiedDietEuropean Continental Ancestry GroupCholestenesPrevalencePhosphatesHypoparathyroidismCohort StudiesDehydrocholesterolsNutritional RequirementsNutrition SurveysHypophosphatemia, FamilialAfrican AmericansHypercalcemiaRadioimmunoassayTandem Mass SpectrometryAbsorptiometry, PhotonAdrenodoxinBostonBody Mass IndexMass SpectrometryAlkaline PhosphataseNutrition PolicyOsteoporosisFractures, BonePostmenopauseChromatography, LiquidIntestinal AbsorptionNebraskaUnited StatesDouble-Blind MethodHyperparathyroidism, SecondaryHyperparathyroidismSpectrophotometry, UltravioletHypocalcemiaLogistic ModelsMultivariate AnalysisMilkOsteocalcinMongoliaOdds RatioChickensHyperparathyroidism, PrimaryHip FracturesBone RemodelingParathyroid GlandsVitamin KBone Diseases, MetabolicFerredoxin-NADP ReductaseAfrican Continental Ancestry GroupFat SubstitutesLow Density Lipoprotein Receptor-Related Protein-2Reference ValuesBone ResorptionRenal Insufficiency, ChronicCholesterol Side-Chain Cleavage EnzymeFollow-Up StudiesVitamin K 1PregnancyBread