Overall , intervention groups obtained higher 25(OH)D concentration than controls and there was obvious dose – response effect between intake dose and 25(OH)D concentration .
Baseline 25(OH)D concentration and age were significant indicators for 25(OH)D concentration .
Conclusions Regional- and age-specific recommended dosages of VitD supplements for population to achieve optimal 25(OH)D concentrations have been suggested
Background / Objectives Optimal doses of vitamin D ( VitD ) supplement in different population s are unclear .
We aim to evaluate the relationship between VitD supplementation and post-intervention serum 25-hydroxyvitamin D [ 25(OH)D ] concentration , to provide a recommended dosage of VitD for achieving an optimal 25(OH)D concentration for different population s .
Effects of different doses of oral cholecalciferol on serum 25(OH)D, PTH, calcium and bone markers during fall and winter in schoolchildren
Background / Objectives : Controversies surround the actual requirements of vitamin D in adolescents . We aim ed to assess the efficacy and safety of different doses of vitamin D in high schoolchildren of Taleghan ( latitude 36.5 ° N ) near Tehran . Subjects/ Methods : In a r and omized double-blind , placebo-controlled trial , 210 subjects , aged 14–20 years , 105 boys and 105 girls were assigned to three groups ; group A ( n=70 ) received 50 000 U oral cholecalciferol monthly ( equal to 1600 U per day ) , group B ( n=70 ) , 50 000 U bimonthly ( equal to 800 U/day ) and group C ( n=70 ) , placebo . The study began in November 2007 and continued until April 2008 . Serum 25(OH)D , parathyroid hormone ( PTH ) , calcium ( Ca ) and bone markers were measured . Results : At baseline , girls had significantly lower concentrations  of 25(OH)D  than boys ( 19.25±16 vs 40.5±14 nmol/l ) . Mean 25(OH)D increased from 32±22 to 60±27.5 and 28.25±14.5 to 45.75±24 in groups A and B , respectively ( P<0.001 ) ; however , it did not change over time in group C ( 29±18 vs 29±17.5 ) . Increment of mean 25(OH)D was higher in group A than in group B ( P<0.01 ) . In all groups , girls had lower concentrations of 25(OH)D than boys  ( P<0.001 ) . Serum Ca increased and PTH decreased in groups A and B ( P<0.001 ) . In group A , osteocalcin ( OC ) and bone-specific alkaline phosphatase increased ( P<0.001 ) , but in group B only OC increased ( P<0.001 ) . Urine C telopeptide and Ca did not change in all three groups ; no case of hypercalcemia was observed . Conclusions : Although monthly administration of 50 000 U vitamin D3 increased serum 25(OH)D significantly , it was apparently not enough to correct vitamin D deficiency especially in girls
Overall , intervention groups obtained higher 25(OH)D concentration than controls and there was obvious dose – response effect between intake dose and 25(OH)D concentration .
Baseline 25(OH)D concentration and age were significant indicators for 25(OH)D concentration .
Conclusions Regional- and age-specific recommended dosages of VitD supplements for population to achieve optimal 25(OH)D concentrations have been suggested
Background / Objectives Optimal doses of vitamin D ( VitD ) supplement in different population s are unclear .
We aim to evaluate the relationship between VitD supplementation and post-intervention serum 25-hydroxyvitamin D [ 25(OH)D ] concentration , to provide a recommended dosage of VitD for achieving an optimal 25(OH)D concentration for different population s .