RESUMO
BACKGROUND: There is conflicting evidence for vitamin D supplementation in childhood asthma. We aimed to systematically synthesise the evidence on the efficacy and safety of vitamin D supplementation in childhood asthma. METHODS: We searched electronic databases (Medline, Embase and Web of Science) and a register (CENTRAL) for randomised controlled trials (RCTs) published until 30 September 2021. RCTs enrolling asthmatic children (1-18â years old) 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 or hospitalisation). We used the Risk of Bias 2 tool for risk of bias assessment. Random-effects meta-analysis with RevMan 5.3 software was performed. The Grading of Recommendations Assessment, Development and Evaluation approach was used to assess the level of certainty of the evidence. RESULTS: 18 RCTs (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 (six studies with 445 participants; risk ratio (RR) 1.13, 95% CI 0.86-1.48; 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 with 1132 participants; RR 0.84, 95% CI 0.65-1.09; I2=58%) (very low-certainty evidence). Vitamin D does not reduce the need for emergency visits (three studies with 361 participants; RR 0.97, 95% CI 0.89-1.07; I2=0%) and hospitalisation (RR: 1.38, 95% CI 0.52-3.66; I2=0%) (low-certainty evidence). CONCLUSION: Very low- to moderate-certainty evidence suggests that vitamin D supplementation might not have any protective effect in childhood asthma.
RESUMO
OBJECTIVE: To determine the role of vitamin D supplementation as an adjunct to standard treatment in childhood asthma. STUDY DESIGN: In this placebo-controlled, blinded, randomized controlled trial, we enrolled 60 children aged 6 to 11 years with moderate persistent asthma and randomly assigned them into intervention (2000 IU per day of vitamin D) and placebo groups (n = 30 each). The primary outcome was asthma control as assessed by the childhood asthma control test (C-ACT) scores at 12 weeks post-randomization. The secondary outcomes were improvement in the forced expiration in 1 s (FEV1 ), fractional exhaled nitric oxide (FeNO), asthma exacerbations, use of systemic steroids, number of emergency visits, post-intervention vitamin D levels, and adverse outcomes. We analyzed by intention to treat. RESULTS: There was no significant difference between the C-ACT score in the two groups (median [first-third quartile] scores were 25 [24-26] in both groups, p = 0.7). Also, there was no significant difference between the two groups in terms of the FEV1 , FeNO, number of exacerbations, emergency visits, hospital admissions, and adverse outcomes. However, the post-intervention vitamin D levels (ng/ml) were significantly higher in the intervention group (35.5 vs. 18.8; p < 0.001). As compared to the baseline, both the groups showed better asthma control at 12 weeks post-intervention, irrespective of the type of intervention. CONCLUSION: Vitamin-D supplementation as an adjunct to standard treatment does not improve asthma control in children.