Department of Occupational Health and Toxicology, School of Public Health, Nanchang University, Nanchang, China.
Jiangxi Province Key Laboratory of Preventive Medicine, Nanchang University, Nanchang, China.
Occup Environ Med. 2019 Mar;76(3):151-156. doi: 10.1136/oemed-2018-105463. Epub 2019 Jan 19.
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.
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.
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.
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.
大量研究表明职业性铅（Pb）暴露增加了心血管疾病的风险。然而，关于 Pb 对心脏传导系统潜在影响的证据仍然稀少且不一致。此外，兰尼碱受体（RyRs）诱导的心脏兴奋-收缩偶联功能障碍被认为是心血管疾病的机制之一。因此，我们研究了职业性 Pb 暴露与心电图传导异常以及 Pb 诱导的心电图异常中 RyRs 之间的关系。
我们调查了 529 名 Pb 冶炼工人，测量了血铅（BPb）、锌原卟啉（ZPP）、心电图结果和 RyR 表达水平。根据 BPb 水平，工人被分为三组：BPb 未升高组、BPb 升高组和 Pb 中毒组。进行了描述性和多变量分析。
与 BPb 未升高组相比，Pb 中毒组 QRS 波群高电压的发生率较高，RyR1 基因表达水平较低（p<0.05）。进一步的无条件多变量逻辑回归分析表明，高 QRS 电压与 BPb 呈正相关（OR=1.045，95%CI 1.014 至 1.078），与 RyR1 表达呈负相关（OR=0.042，95%CI 0.002 至 0.980），在调整了潜在混杂因素后。此外，多元线性回归分析表明，在调整了潜在混杂因素后，QTc 间期与 ZPP 呈正相关（β=0.299，95%CI 0.130 至 0.468）。
我们的研究提供了证据表明，职业性 Pb 暴露可能与更差的心电图结果（高 QRS 电压）相关，这可能与 RyR1 水平降低有关。
