Objectives A significant number of researches have evidenced that occupational lead (Pb) exposure increased risks of cardiovascular disease. However, evidences about the potential effects of Pb on the cardiac conduction system are sparse and inconclusive. Besides, ryanodine receptors (RyRs) induced dysfunction of cardiac excitation contraction coupling which is considered to be one of the mechanisms in cardiovascular diseases. Therefore, we examined the association between occupational Pb exposure and ECG conduction abnormalities, as well as RyRs in Pb-induced ECG abnormalities.
Methods We investigated 529 Pb smelter workers, and measured blood lead (BPb), zinc protoporphyrin (ZPP), ECG outcomes and RyR expression levels. Based on BPb levels, the workers were divided into three groups: the BPb not elevated group, the BPb elevated group and the Pb poisoning group. Descriptive and multivariable analyses were performed.
Results Compared with the BPb not elevated group, the Pb poisoning group had a higher incidence of high QRS voltage, and a lower level of RyR1 gene expression (p<0.05). Further unconditional multivariable logistic regression analyses showed that high QRS voltage was positively related to BPb (OR=1.045, 95% CI 1.014 to 1.078) and inversely associated with RyR1 expression (OR=0.042, 95% CI 0.002 to 0.980) after adjusting for potential confounders. In addition, multiple linear regression analyses showed that the QTc interval was positively associated with ZPP (β=0.299, 95% CI 0.130 to 0.468) after adjusting for potential confounders.
Conclusions Our study provided evidences that occupational exposure to Pb may be associated with worse ECG outcomes (high QRS voltage), which might be related to decreased levels of RyR1.
- hygiene / occupational hygiene
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JX, GD and YZ contributed equally.
Contributors GF conceived and developed the overall research plan, designed the research and had primary responsibility for final content. JX, GD, YZ and GF analysed the data; JX, GD, YZ, GF and WY wrote the paper; FZ, GD, JW, HJ, YL, YC, LO, YZ, DB and CF conducted the research. All authors read and approved the final manuscript.
Funding This work was supported by The National Natural Science Foundation of China (Nos. 81273120, 81673222, 81760599), Special Foundation for State Major Basic Research Program of China (No. 2015FY111100), Nanchang University Breeding Grant of Major Scientific and Technological Achievements for Comprehensive Reform Special Project (No.9202-0210210807), Innovation Project of Jiangxi Province for Graduate Student (No. YC2013-S004) and Innovation Project of Nanchang University for Graduate Student (No. cx2016288).
Competing interests None declared.
Patient consent Obtained.
Ethics approval The Clinical Ethics Committee of First Affiliated Hospital of Nanchang University.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement The data used for this study are available on reasonable request from the corresponding author.
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