To assess the efficacy of selenium supplementation for prevention of Kashin-Beck Osteoarthropathy in children.
We searched eight electronic databases and seven journals (upto July 2007) to identify randomized controlled trials (RCTs) and prospective non-RCTs comparing selenium supplementations with placebo or no intervention for preventing Kashin-Beck disease (KBD). The methodological qualities of included studies were assessed according to the guidelines of Cochrane Handbook for Systematic Reviews of Interventions for RCTs and the method described by Deeks et al. for non-RCTs. Outcomes were presented as Peto-odds ratios (Peto-ORs) with 95% confidence intervals (95% CIs) based on fixed effect model. The number needed to treat (NNT) was calculated. Meta-regression was also conducted to explore the possible impacts of potential confounding variables (place of study, age, selenium form, etc.) of included trials on the incidence of KBD.
Five RCTs and 10 non-RCTs were included in this review. The methodological quality of included studies was low. The pooled Peto-OR and NNT favoring selenium supplement was 0.13 (95% CI: 0.04-0.47) and 21 in RCTs, and 0.16 (95% CI: 0.09-0.30) and 26 in non-RCTs. Meta-regression indicated that the effect of potential confounding variables on KBD incidence was not statistically significant. One trial reported the side effects of nausea and vomiting in the process of selenium supplementation.
Current evidence supports the benefits of selenium supplementation for prevention of KBD in children. However, the evidence was limited by potential biases and confounders. Large, well-designed trials are still needed.