Mortality Benefits of Vitamin A Are Not Affected by Varying Frequency, Total Dose, or Duration of Supplementation:

Background:Although vitamin A supplementation reduces child mortality, it remains unclear whether dosing frequency, total dose, or duration modifies effectiveness.Objective:Determine whether mortality effects of vitamin A vary by dosing frequency, total dose, or duration.Methods:Meta-analysis of randomized controlled trials, identified by systematic review and expert opinion, utilizing relatively standard World Health Organization doses in children <5 years. Meta-regression evaluated whether mortality effects varied by dosing frequency, total dose, or supplementation duration.Results:Identified 17 trials, including 1,180,718 children, mean (standard deviation [SD]) age 31.5 (15.4) months at baseline. Supplementation frequency ranged every 3 months-every 2 years, supplementation duration 4-60 months (mean = 15.4; SD = 12.8), and total dose 134,361-2,200,000 IU (mean = 667,132 IU; SD = 540,795). Compared with control, vitamin A reduced mortality 22% (95% confidence interval [CI] = 10-32; P = 0.002). This pr...