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    ABSTRACT: Abstract Context: Observational studies have suggested a relationship between vitamin D status and asthma-related respiratory outcomes. The benefit of vitamin D supplementation for pulmonary function, symptoms and exacerbations is not well established. Objective: To systematically review paediatric clinical trials investigating the role of vitamin D on asthma-related respiratory outcomes. Data sources: MEDLINE, EMBASE and CENTRAL were searched January 2014. No date or language restrictions. Study selection: Clinical trials reporting asthma-related respiratory outcomes following vitamin D administration at a dose equal or greater than 500 IU per day were included and reviewed independently by two authors for full systematic review eligibility. Data extraction: Two reviewers independently extracted and verified predefined data fields. Results: We identified five studies that met study eligibility and assessed final data synthesis. The median trial size was 48 participants (range 17-430) and the average daily dose of cholecalciferol ranged from 500 to 2,000 IU/day. Overall study methodological quality was high, but some heterogeneity in population and vitamin D dosing regimen was evident. Meta-analysis suggested a statistically significant reduction (RR 0.41, CI 0.27 to 0.63) in asthma exacerbation with vitamin D therapy. Limitations: Due to variability in outcome selection and missing data, it was not possible to perform meta-analysis for pulmonary function testing and asthma symptom scores. Vitamin D-related adverse events were not considered in four of five papers. Conclusions: Available evidence from this systematic review suggests that high dose vitamin D may prevent asthma exacerbation. This should be confirmed through larger well-designed randomized controlled trials.
    Journal of Asthma 11/2014; · 1.83 Impact Factor
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    ABSTRACT: Asthma in the elderly is poorly understood and vitamin D deficiency and insufficiency are very common in older individuals. We studied the role of vitamin D in elderly asthmatics.
    Journal of Allergy and Clinical Immunology 02/2014; 10(1):48. · 11.25 Impact Factor
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    ABSTRACT: Vitamin D deficiency may represent a modifiable risk factor to improve outcome in severe illness. The efficacy of high-dose regimens in rapid normalization of vitamin D levels is uncertain. We conducted a systematic review of pediatric clinical trials administering high-dose vitamin D to evaluate 25-hydroxyvitamin D (25[OH]D) response and characteristics associated with final 25(OH)D levels by using Medline, Embase, and the Cochrane Central Register of Controlled Trials, including reference lists of systematic reviews and eligible publications. Uncontrolled and controlled trials reporting 25(OH)D levels after high-dose (≥1000 IU) ergocalciferol or cholecalciferol were selected. Two reviewers independently extracted and verified predefined data fields. We identified 88 eligible full-text articles. Two of 6 studies that administered daily doses approximating the Institute of Medicine's Tolerable Upper Intake Level (1000-4000 IU) to vitamin D-deficient populations achieved group 25(OH)D levels >75 nmol/L within 1 month. Nine of 10 studies evaluating loading therapy (>50 000 IU) achieved group 25(OH)D levels >75 nmol/L. In meta-regression, baseline 25(OH)D, regimen type, dose, age, and time factors were associated with final 25(OH)D levels. Adverse event analysis identified increased hypercalcemia risk with doses >400 000 IU, but no increased hypercalcemia or hypercalciuria with loading doses <400 000 IU (or 10 000 IU/kg). Few studies in adolescents evaluated loading dose regimens >300 000 IU. Rapid normalization of vitamin D levels is best achieved by using loading therapy that considers disease status, baseline 25(OH)D, and age (or weight). Loading doses >300 000 IU should be avoided until trials are conducted to better evaluate risk and benefit. Copyright © 2015 by the American Academy of Pediatrics.
    Pediatrics 12/2014; · 5.30 Impact Factor