Effect of vitamin D on lung function assessed by forced oscillation technique in asthmatic children with vitamin D deficiency: A randomized double-blind placebo-controlled trial

Abstract

Background:The role of vitamin D and asthma in pulmonary function changes showed conflicting result.Objective: To evaluate if vitamin D treatment would improve lung function assessed by forced oscillation technique (FOT) in vitamin D deficient asthmatic children. Methods:A randomized double-blind placebo-controlled trial was performed in children, aged 3-18 years with well controlled asthma. Serum total 25(OH)D and FOT parameters including respiratory resistance at 5 Hz (R5), at 20 Hz (R20), respiratory reactance at 5 Hz (X5) and area of reactance (ALX), resonance frequency (Fres) were evaluated at baseline, 1 month and 3 months. Vitamin D deficient patients (serum total 25(OH)D < 20 ng/ml) were randomized to receive treatment with vitamin D2 (tVDD) or placebo (pVDD). Non-vitamin D deficient patients (nVDD) received placebo as a control group.Results: A total of 84 children were recruited, 43 patients in nVDD group, 20 in tVDD group and 21 in pVDD group. There were no significant differences in age, sex, height and weight among groups. There were no significant differences of FOT parameters among groups at all visits. There was a trend toward decrease in R5/R20 from baseline to 1 month and 3 months visit in all groups, but the statistically significant improvement was observed only in nVDD group. Serum 25(OH)D showed no correlation with % predicted of FOT measures. Conclusion:Vitamin D treatment in asthmatic children who had vitamin D deficiency may have no short term beneficial effect on pulmonary function assessed by FOT. Vitamin D supplementation in all asthmatic patient needs further study.

Vitamin D supplementation in childhood asthma: a systematic review and meta-analysis of randomised controlled trials

“…13 out of 18 were performed in the outpatient setting [ 9 – 11 , 14 – 16 , 21 , 25 , 29 , 31 , 32 , 34 , 36 ]. Six trials [ 14 , 16 , 17 , 29 , 34 , 35 ] enrolled only vitamin D-deficient (VDD) or vitamin D-insufficient participants. The remaining 12 did not prespecify vitamin D deficiency as an entry criterion, although many participants were VDD.…”

“…We used the RoB2 tool for the risk of bias assessment ( e-figure 1 ). Six trials had some bias arising from the randomisation process [ 9 , 10 , 17 , 29 , 33 , 35 ]. Another two had some concerns in handling missing data [ 8 , 9 ].…”

“…None of the trials enrolled children exclusively in the deficient range (<12 ng·mL −1 ); therefore, we included RCTs with participants having 25(OH)D levels <20 ng·mL −1 before enrolment collectively under the deficient/insufficient category for subgroup analysis. Three trials enrolled children with 25(OH)D levels <20 ng·mL −1 [ 14 , 29 , 35 ]. However, only one study provided data on asthma exacerbation [ 14 ].…”

Vitamin D Supplementation and Allergic Diseases during Childhood: A Systematic Review and Meta-Analysis

“…We identified 3372 records with our search strategy, and 115 full-text articles were assessed for eligibility. After excluding 83 articles, 32 RCTs with 2347 participants were included in the review ( Figure 1 ) [ 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 ]. Among the 32 RCTs, 18 RCTs were for children with asthma [ 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 ...…”

“…Five RCTs had high risk of bias in handling missing data [ 37 , 46 , 55 , 59 , 60 ]. Fourteen RCTs had unclear risk of bias in at least one domain [ 30 , 31 , 34 , 35 , 36 , 38 , 39 , 41 , 49 , 51 , 53 , 54 , 56 , 58 ]. Nine RCTs had low risk in all domains [ 32 , 33 , 42 , 43 , 44 , 45 , 47 , 48 , 52 ].…”