Status and potential diagnostic roles of essential trace elements in Kashin- Beck disease patients.

Background: This updated and comprehensive meta-analysis study sought to explore the changes of seven essential trace elements, including selenium (Se), iron (Fe), zinc (Zn), manganese (Mn), fluorine (F), iodine (I) and copper (Cu) in Kashin-Beck disease (KBD) patients compared with healthy individuals. The findings of the current study will provide a valuable reference for implementation of early clinical intervention and prevention of KBD.

Methods: All related articles included in this review were retrieved from the following databases: Chinese National Knowledge Infrastructure (CNKI), Wan Fang Data, China Biology Medicine disc (CBM disc), PubMed and Web of Science up to April 30, 2020. The following combination keywords were used as the search criteria: "(Kashin-Beck disease OR KBD) AND ((selenium OR iron OR zinc OR manganese OR fluorine OR iodine OR copper) OR (Se OR Fe OR Zn OR Mn OR F OR I OR Cu))". All statistical analyses were performed using RevMan 5.3 and Stata 16.0 software.

Results: A total of 55 articles were included in the current study. Meta-analysis showed that the levels of serum Se (SMD = -2.37, 95 % CI: -1.58 to -0.72, P < 0.00001), hair Se (SMD = -2.19, 95 % CI: -3.05 to -1.33, P < 0.00001), urinary Se (SMD = -2.36, 95 % CI: -3.26 to -1.46, P < 0.00001) and erythrocyte Se (SMD = -5.12, 95 % CI: -9.55 to -0.69, P = 0.02) were significantly lower in KBD patients compared with the levels in healthy controls. Then, the findings showed that the levels of serum F (SMD = -0.58, 95 % CI: -1.04 to -0.12, P = 0.01) and hair I (SMD = -0.57, 95 % CI: -1.06 to -0.08, P = 0.02) in patients were substantially lower than that in controls. Analysis showed that the levels of hair Zn (SMD = 0.26, 95 % CI: 0.04 to 0.49, P = 0.02) and hair Mn (SMD = 0.55, 95 % CI: 0.24 to 0.85, P = 0.0005) were markedly higher in patients compared with the levels in healthy controls. Notably, urinary Se (AUC = 0.7851, P = 0.0235, Sensitivity = 81.82 %, Specificity = 81.82 %) showed a good diagnostic value for KBD.

Conclusions: The findings of the current study showed that the levels of Se, serum F and hair I were lower in patients with KBD compared with those in healthy controls, whereas the levels of hair Zn and hair Mn were higher in KBD patients compared with the levels in controls. This outcome would be further validated in our future studies. Of note, these results indicated that Se, F and I deficiencies were associated with the pathogenesis of KBD.