Meta-analysis of Zn, Cu and Fe in the hair of Chinese children with recurrent respiratory tract infection

Abstract

Trace elements play an important role in maintaining the normal metabolic and immune function. The onset of recurrent respiratory tract infection (RRI) is associated with the immune function, genetic factors and nutritional status. However, the association between the levels of trace elements and RRI remains inconclusive. We aimed to investigate the alterations of hair levels of zinc (Zn), copper (Cu) and iron (Fe) in Chinese children with RRI by performing a meta-analysis. A predefined electronic databases search was performed to identify eligible studies for the analysis of hair Zn, Cu or Fe levels in Chinese children with RRI. Thirteen studies were included. RRI patients displayed significantly lower levels of hair Zn (13 studies, random effects SMD: − 1.215, 95% CI: − 1.704 to − 0.725, p < 0.0001), Cu (11 studies, random effects SMD: − 0.384, 95% CI: − 0.717 to − 0.052, p = 0.023) and Fe (12 studies, random effects SMD: − 0.569, 95% CI: − 0.827 to − 0.312, p < 0.0001) compared with controls. No evidence of publication bias was observed. Sensitivity analysis did not change the results significantly. In conclusion, the deficiency of Zn, Cu and Fe may be contributing factors for the susceptibility of RRI in Chinese children. However, more studies in different ethnicities should be performed in the future.

Key Words::

• Hair
• zinc
• copper
• iron
• children
• recurrent respiratory tract infection

Declaration of interest: The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.

This study was supported by Grants from the National Basic Research Program of China 973 Program (nos. 2012CB517602 and 2013 CB530604), the National Natural Science Foundation of China (nos. 81170635 and 81270785) and the Research and innovation Project for College Graduates of Jiangsu Province, China (grant number CXLX13_556).