RT Journal Article SR Electronic T1 ECG conduction disturbances and ryanodine receptor expression levels in occupational lead exposure workers JF Occupational and Environmental Medicine JO Occup Environ Med FD BMJ Publishing Group Ltd SP 151 OP 156 DO 10.1136/oemed-2018-105463 VO 76 IS 3 A1 Jie Xie A1 Guihua Du A1 Yuanyuan Zhang A1 Fankun Zhou A1 Junfang Wu A1 Huan Jiao A1 Yanshu Li A1 Ying Chen A1 Lu Ouyang A1 Dandan Bo A1 Chang Feng A1 Wei Yang A1 Guangqin Fan YR 2019 UL http://oem.bmj.com/content/76/3/151.abstract AB 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.