Inclusion of 95 % range in the model to account for inter-individual variability increased the predicted intake of vitamin D needed to maintain serum 25(OH)D ≥ 50 nmol/l to 930 IU/d .
A randomized, controlled lower leg growth study of vitamin D supplementation to healthy children during the winter season
Background : The deceleration of longitudinal growth in children during winter occurs simultaneously with a decrease in the number of daylight hours and a reduction in vitamin D status . Due to worries about deleterious effects on bone of a relative insufficiency , vitamin D supplementation to healthy children has been suggested . Aim : To see whether supplementation of vitamin D to healthy children during winter affects seasonal growth . Subjects and methods : Twelve girls and eight boys aged 6.2 - 13.7 ( mean 9.8 ) years , all healthy , were enrolled in a double-blind , r and omized , placebo-controlled cross-over study with two 4-week treatment periods and 2-week run-in and wash-out periods . Vitamin D 3 600 IU was given in one tablet ABCDin ® daily .  Knemometry  of the right lower leg was performed on the first and last day of each period . Results : Lower leg growth rates ( mean - SEM ) during placebo and vitamin D 3 administration were identical : 0.28 - 0.04 mm per week ( p = 0.94 , t = 0.1 , 95 % CI : m 0.12 - 0.13 mm per week ) . Conclusion : Supplementation with vitamin D 3 600 IU day m 1 to healthy children during winter may not improve seasonal growth . Therefore , supplementation may not be recommended on the grounds of concerns about growth ; however firm conclusions await r and omized long-term studies
Inclusion of 95 % range in the model to account for inter-individual variability increased the predicted intake of vitamin D needed to maintain serum 25(OH)D ≥ 50 nmol/l to 930 IU/d .