Background Exposure to zinc was suggested to be associated with pulmonary damage, but whether zinc exposure affects lung function remains unclear.
Objectives To quantify the association between urinary zinc and lung function and explore the potential mechanisms.
Methods Urinary zinc and lung function were measured in 3917 adults from the Wuhan-Zhuhai cohort and were repeated after 3 years of follow-up. Indicators of systemic inflammation (C reactive protein), lung epithelium integrity (club cell secretory protein-16) and oxidative damage (8-hydroxy-2′-deoxyguanosine and 8-isoprostane) were measured at baseline. Linear mixed models were used to estimate the exposure–response relationship between urinary zinc and lung function. Mediation analyses were conducted to assess mediating roles of inflammation and oxidative damage in above relationships.
Results Each 1-unit increase in log-transformed urinary zinc values was associated with a 35.72 mL decrease in forced vital capacity (FVC) and a 24.89 mL decrease in forced expiratory volume in 1 s (FEV1) in the baseline analyses. In the follow-up analyses, there was a negative association between urinary zinc and FVC among participants with persistent high urinary zinc levels, with an estimated change of −93.31 mL (95% CI −178.47 to −8.14). Furthermore, urinary zinc was positively associated with restrictive ventilatory impairment. The mediation analyses suggested that C reactive protein mediated 8.62% and 8.71% of the associations of urinary zinc with FVC and FEV1, respectively.
Conclusion Urinary zinc was negatively associated with lung function, and the systemic inflammation may be one of the underlying mechanisms.
- clinical epidemiology
- cytokine biology
- oxidative stress
- respiratory measurement
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Contributors All authors meet the criteria of authorship. MZ and WC designed the study. MZ, LX, SY, BW, TS, AT, XW, GM and WC collected the data. MZ and WC performed the statistical analysis, interpreted the results, and drafted the manuscript. LX, SY, BW, TS, AT, XW and GM critically reviewed the manuscript. All authors approved the final version of the manuscript and agreed to be accountable for all aspects of the work.
Funding This work was supported by the National Natural Science Foundation of China’s Major Research Programme under grant number 91843302; and the Key Programme of the National Natural Science Foundation of China under grant number 91543207.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval The research protocol was approved by the Ethics and Human Subject Committee of Tongji Medical College, Huazhong University of Science and Technology (no. 2011–17).
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available on reasonable request. The datasets generated and analysed during the current study are available from the corresponding author on reasonable request (e-mail, email@example.com).
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