[A systematic review regarding the effects of different kinds of selenium supplementations on Kaschin-Beck disease]

To systematically assess the efficacy of different programs regarding the selenium supplementation formulae used for prevention and treatment of Kaschin-Beck disease (KBD) in children.

PubMed, EMBASE, Cochrane Library, SCI expanded, CNKI (Chinese National Knowledge Infrastructure), VIP (Chinese Science and Technique Journals Database), CBM (The Chinese Biomedical Database), Wanfang Database, CSCD (Chinese Science Citation Database) had been electronically searched. All the searching processes were up-dated to Dec 2012 to identify randomized trials (RCTs) and non-RCTs to compare the selenium supplementation formulae with placebo or with no intervention. Two reviewers assessed the methodological quality of the study design, including RCTs or non-RCTs according to Cochrane Handbook for Systematic Reviews of Interventions 5.1 or a checklist described by Deeks JJ, et al, respectively. Data was extracted independently.

There were 14 RCTs and 12 non-RCTs papers included, but showing low methodological quality. Data from Meta analysis showed that selenium supplementation had caused the following progresses: radiologic improvement (RR = 3.28, 95%CI: 2.06 - 5.22), higher hair selenium (SMD = 2.05, 95%CI: 1.00 - 3.11) lower new radiologic lesions (OR = 0.18, 95%CI: 0.09 - 0.36) than in the placebo or with no treatment groups. Both selenium and vitamin C supplementation did not show differences in radiologic improvement of metaphysis (RR = 1.01, 95%CI: 0.84 - 1.22). Combination of selenium and vitamin E supplementation showed higher radiologic improvement than the placebo group. Combination of selenium and vitamin C supplementation had no influence on the difference in radiologic improvement or hair selenium than selenium supplementation. Selenium-enriched yeast showed higher radiologic improvement than sodium selenite (70.83% vs. 48.84%, P < 0.05). Selenium fertilization showed higher radiologic improvement than the non-treatment group (RR = 3.98, 95%CI: 2.25 - 7.05). Comprehensive intervention program and 'grain drying approach' also showed certain effects.

Selenium supplementation could lead to better radiologic improvement and hair selenium, with lower new radiologic lesions. Current evidence supported its benefits on prevention and treatment of KBD. Large sample sized and well-designed trials together with the reporting on adverse outcome remained necessary.