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

Abstract

BackgroundThere is conflicting evidence for vitamin D supplementation in childhood asthma. We aimed to systematically synthesize the evidence on the efficacy and safety of vitamin D supplementation in childhood asthma.MethodsWe searched electronic databases (Medline, Embase, Web of Science) and register (CENTRAL) for randomised controlled trials (RCTs) published until September 30, 2021. RCTs enrolling asthmatic children (1–18 years) and comparing vitamin D against placebo/routine care were included if they met at least one of the endpoints of interest (asthma attacks, emergency visits, hospitalisation). We used the Risk of Bias (RoB) 2 tool for risk of bias assessment. Random-effects meta-analysis with RevMan 5.3 software was done. The GRADE approach was used to assess the level of certainty of the evidence.ResultsEighteen RCTs (n=1579 participants) were included. The pooled meta-analysis did not find a significant effect of vitamin D supplementation on asthma attacks requiring rescue systemic corticosteroids (6 studies, 445 participants, Risk ratio: 1.13; 95% CI: 0.86 to 1.48, I2–0%) (Moderate-certainty evidence). In addition, there was no significant difference in the proportion of children with asthma attacks of any severity (11 trials, 1132 participants, RR: 0.84; 95% CI: 0.65 to 1.09; I2–58%) (Very-low certainty evidence). Vitamin D does not reduce the need for emergency visits (3 studies, 361 participants, RR: 0.97; 95% CI: 0.89 to 1.07, I2–0%) and hospitalisation (RR: 1.38; 95% CI: 0.52 to 3.66, I2–0%) (Low certainty evidence).ConclusionVery low to moderate certainty evidence suggests that vitamin D supplementation might not have any protective effect in childhood asthma.

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

“…Our findings are consistent with those of a recently published meta-analysis, which did not find protective effects of vitamin D supplementation on reducing asthma exacerbation in children either [ 13 ]. There are many factors that contribute to the ineffectiveness of vitamin D supplementation in children with asthma.…”

“…However, it is unclear whether vitamin D supplementation can improve the outcomes of children with allergic diseases. The effects of vitamin D supplementation on certain allergic diseases, such as asthma and atopic dermatitis, have been discussed in several systematic reviews (SRs) [ 11 , 12 , 13 , 14 ]. However, the effects of vitamin D supplementation on all allergic diseases in children have not been examined.…”

“…Therefore, a holistic overview of the treatment effect of vitamin D on childhood allergic diseases is necessary. Some of the previous SRs did not identify the individuals who might derive the greatest benefit from vitamin D supplementation and did not examine the optimal regimen of vitamin D [ 12 , 13 , 14 ]. To resolve the above issues, we performed an SR and meta-analysis to investigate the effects of vitamin D supplementation on childhood allergic diseases.…”

Weight Loss and Vitamin D Improve Hyporesponsiveness to Corticosteroids in Obese Asthma

“…The trials enrolled patients with significant differences in the selection of participants, baseline VitD levels and dosage of VitD supplementation. Some systematic reviews of RCTs concluded that high-dose VitD may be effective in paediatric asthma [39]; however, others could not find significant evidence favouring the use of this complementary therapy in children and adults [40].…”

Recent advances in vitamin D implications in chronic respiratory diseases

“…Out of 18 RCTs, the pooled meta-analysis did not find any significant correlation between vitamin D supplementation on asthma attacks requiring rescue systemic corticosteroids. In addition, vitamin D did not reduce the severity nor the hospitalization rates of these patients [ 27 ]. Similarly, Nitzan et al .…”