title: Vitamin D3 dose requirement to raise 25-hydroxyvitamin D to desirable levels in adolescents: results from a randomized controlled trial.
abstract: Several organizations issued recommendations on desirable serum 25-hydroxy vitamin D [25(OH)D] levels and doses of vitamin D needed to achieve them. Trials allowing the formulation of evidence-based recommendations in adolescents are scarce. We investigated the ability of two doses of vitamin D3 in achieving recommended vitamin D levels in this age group. Post hoc analyses on data from a 1-year double-blind trial that randomized 336 Lebanese adolescents, aged 13 ± 2 years, to placebo, vitamin D3 at 200 IU/day (low dose), or 2000 IU/day (high dose). Serum 25(OH)D level and proportions of children achieving levels ≥ 20 ng/mL and 30 ng/mL were determined. At baseline, mean 25(OH)D was 15 ± 7 ng/mL, 16.4 ± 7 ng/mL in boys, and 14 ± 8 ng/mL in girls, p=0.003, with a level ≥ 20 ng/mL in 18% and ≥ 30 ng/mL in 5% of subjects. At 1 year, mean levels were 18.6 ± 6.6 ng/mL in the low-dose group, 17.1 ± 6 ng/mL in girls, and 20.2 ± 7 ng/mL in boys, p=0.01, and 36.3 ± 22.3 ng/mL in the high-dose group, with no sex differences. 25(OH)D increased to ≥ 20 ng/mL in 34% of children in the low-dose and 96% in the high-dose group, being higher in boys in the low-dose arm only; it remained ≥ 30 ng/mL in 4% of children in the low-dose arm but increased to 64% in the high-dose arm. Baseline 25(OH)D level, body mass index (BMI), and vitamin D dose assigned were the most significant predictors for reaching a 25(OH)D level ≥ 20 ng/mL and 30 ng/mL. A daily dose of 2000 IU raised 25(OH)D level ≥ 20 ng/mL in 96% of adolescents (98% boys versus 93% girls). Dose-response studies are needed to determine in a definitive manner the daily allowance of vitamin D for Middle Eastern adolescents with a similar profile.
authors.affiliation: Scholars in Health Research Program, American University of Beirut Medical Center, Beirut, Lebanon; Vascular Medicine Program, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: Laila
authors.initials: L
authors.lastname: Al-Shaar
authors.forename: Rania
authors.initials: R
authors.lastname: Mneimneh
authors.lastname: Nabulsi
authors.forename: Joyce
authors.initials: J
authors.lastname: Maalouf
authors.forename: Ghada El-Hajj
authors.initials: Gel-H
authors.lastname: Fuleihan
mesh_terms: D000293:Adolescent; D002648:Child; D002762:Cholecalciferol / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D011863:Radioimmunoassay; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; D002762:Cholecalciferol; C104450:25-hydroxyvitamin D
keywords: ADOLESCENTS; DESIRABLE LEVELS; ES; GUIDELINES; IOM; RDA; VITAMIN D DOSE