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 .
Effect of High-Dose vs Standard-Dose Wintertime Vitamin D Supplementation on Viral Upper Respiratory Tract Infections in Young Healthy Children
Importance Epidemiological studies support a link between low 25-hydroxyvitamin D levels and a higher risk of viral upper respiratory tract infections . However , whether winter supplementation of vitamin D reduces the risk among children is unknown . Objective To determine whether high-dose vs st and ard-dose vitamin D supplementation reduces the incidence of wintertime upper respiratory tract infections in young children . Design , Setting , and Participants A r and omized clinical trial was conducted during the winter months between September 13 , 2011 , and June 30 , 2015 , among children aged 1 through 5 years enrolled in TARGet Kids ! , a multisite primary care practice –based research network in Toronto , Ontario , Canada . Interventions Three hundred forty-nine participants were r and omized to receive 2000 IU/d of vitamin D oral supplementation ( high-dose group ) vs 354 participants who were r and omized to receive 400 IU/d ( st and ard-dose group ) for a minimum of 4 months between September and May. Main Outcome Measures The primary outcome was the number of laboratory-confirmed viral upper respiratory tract infections based on parent-collected nasal swabs over the winter months . Secondary outcomes included the number of influenza infections , noninfluenza infections , parent-reported upper respiratory tract illnesses , time to first upper respiratory tract infection , and serum 25-hydroxyvitamin D levels at study termination . Results Among 703 participants who were r and omized ( mean age , 2.7 years , 57.7 % boys ) , 699 ( 99.4 % ) completed the trial . The mean number of laboratory-confirmed upper respiratory tract infections per child was 1.05 ( 95 % CI , 0.91 - 1.19 ) for the high-dose group and 1.03 ( 95 % CI , 0.90 - 1.16 ) for the st and ard-dose group , for a between-group difference of 0.02 ( 95 % CI , −0.17 to 0.21 ) per child . There was no statistically significant difference in number of laboratory-confirmed infections between groups ( incidence rate ratio [ RR ] , 0.97 ; 95 % CI , 0.80 - 1.16 ) . There was also no significant difference in the median time to the first laboratory-confirmed infection : 3.95 months ( 95 % CI , 3.02 - 5.95 months ) for the high-dose group vs 3.29 months ( 95 % CI , 2.66 - 4.14 months ) for the st and ard-dose group , or number of parent-reported upper respiratory tract illnesses between groups ( 625 for high-dose vs 600 for st and ard-dose groups , incidence RR , 1.01 ; 95 % CI , 0.88 - 1.16 ) . At study termination , serum 25-hydroxyvitamin D levels were 48.7 ng/mL ( 95 % CI , 46.9 - 50.5 ng/mL ) in the high-dose group and 36.8 ng/mL ( 95 % CI , 35.4 - 38.2 ng/mL ) in the st and ard-dose group . Conclusions and Relevance Among healthy children aged 1 to 5 years , daily administration of 2000 IU compared with 400 IU of vitamin D supplementation did not reduce overall wintertime upper respiratory tract infections . These findings do not support the routine use of high-dose vitamin D supplementation in children for the prevention of viral upper respiratory tract infections . Trial Registration clinical trials.gov Identifier :
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 .