Effects of five types of selenium supplementation for treatment of Kashin-Beck disease in children: a systematic review and network meta-analysis

Xie D, Liao Y, Yue J, Zhang C, Wang Y, Deng C, Chen L · BMJ Open

All five forms produced more metaphyseal X-ray improvement than placebo, with selenium salt ranked highest and sodium selenite plus vitamin C lowest. The authors then downgrade their own primary outcomes from high to low or very low on GRADE, and state that the ranking may be misleading and the evidence insufficient to say which form is best.

Population

2,931 children with Kashin-Beck disease across 15 randomized controlled trials

Intervention

Five forms of selenium — selenium salt, sodium selenite, selenium-enriched yeast, and sodium selenite with vitamin E or vitamin C

Comparator

Placebo, and each other

Limitations

GRADE quality low to very low by the authors' own assessment. The endpoint is repair of metaphyseal lesions on X-ray in children with an established deficiency disease — a different thing from cartilage protection in a replete adult. PROSPERO CRD42016051874.