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Workplace
Original article
Heart rate variability and peripheral nerve conduction velocity in relation to blood lead in newly hired lead workers
  1. Cai-Guo Yu1,2,
  2. Fang-Fei Wei1,
  3. Wen-Yi Yang1,
  4. Zhen-Yu Zhang3,
  5. Blerim Mujaj1,
  6. Lutgarde Thijs1,
  7. Ying-Mei Feng2,
  8. Jan A Staessen1,4
  1. 1 Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium
  2. 2 Department of Endocrinology, Beijing Lu He Hospital and Key Laboratory of Diabetes Prevention and Research, Capital Medical University, Beijing, China
  3. 3 Institut Universitaire de Médecine Sociale et Préventive, University of Lausanne, Lausanne, Switzerland
  4. 4 Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
  1. Correspondence to Dr Jan A Staessen, Department of Cardiovascular Diseases, University of Leuven, Leuven 3000, Belgium; jan.staessen{at}med.kuleuven.be

Abstract

Objectives Previous studies relating nervous activity to blood lead (BL) levels have limited relevance, because over time environmental and occupational exposure substantially dropped. We investigated the association of heart rate variability (HRV) and median nerve conduction velocity (NCV) with BL using the baseline measurements collected in the Study for Promotion of Health in Recycling Lead (NCT02243904).

Methods In 328 newly hired men (mean age 28.3 years; participation rate 82.7%), we derived HRV measures (power expressed in normalised units (nu) in the high-frequency (HF) and low-frequency (LF) domains, and LF/HF) prior to long-term occupational lead exposure. Five-minute ECG recordings, obtained in the supine and standing positions, were analysed by Fourier transform or autoregressive modelling, using Cardiax software. Motor NCV was measured at the median nerve by a handheld device (Brevio Nerve Conduction Monitoring System, NeuMed, West Trenton, NJ, USA). BL was determined by inductively coupled plasma mass spectrometry.

Results Mean BL was 4.54 µg/dL (IQR 2.60–8.90 µg/dL). Mean supine and standing values of LF, HF and LF/HF were 50.5 and 21.1 nu and 2.63, and 59.7 and 10.9 nu and 6.31, respectively. Orthostatic stress decreased HF and increased LF (p<0.001). NCV averaged 3.74 m/s. Analyses across thirds of the BL distribution and multivariable-adjusted regression analyses failed to demonstrate any association of HRV or NCV with BL.

Conclusions At the exposure levels observed in our study, autonomous nervous activity and NCV were not associated with BL.

Trial registration number NCT02243904

  • lead
  • neurophysiology
  • cardiovascular
  • materials, exposures and occupational groups
  • healthcare workers

This is an open access article distributed in accordance with the Creative Commons Attribution 4.0 Unported (CC BY 4.0) license, which permits others to copy, redistribute, remix, transform and build upon this work for any purpose, provided the original work is properly cited, a link to the licence is given, and indication of whether changes were made. See: https://creativecommons.org/licenses/by/4.0/.

https://doi.org/10.1136/oemed-2018-105379

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    Footnotes

    • Contributors JAS designed the SPHERL study and secured funding. CGY, WYY and BM constructed the database for analysis. CGY and FFW did the statistical analysis. CGY and JAS wrote the first draft of the manuscript. All authors contributed to the interpretation of the results and performed a critical revision of the manuscript and all approved the final version before submission. The corresponding author had full access to all of the data in the study and had the responsibility for guaranteeing the integrity of the data and the decision to submit the manuscript for publication.

    • Funding The European Union (HEALTH-F7-305507 HOMAGE) and the European Research Council (Advanced Researcher Grant 2011-294713-EPLORE and Proof-of-Concept Grant 713601-uPROPHET), the European Research Area Net for Cardiovascular Diseases (JTC2017-046- PROACT) and the Fonds voor Wetenschappelijk Onderzoek Vlaanderen, Ministry of the Flemish Community, Brussels, Belgium (G.0881.13) currently support the Research Unit Hypertension and Cardiovascular Research. An unrestricted grant from the International Lead Association (www.ila-lead.org) partially supported the data collection and analysis of the current data.

    • Disclaimer The funding source had no role in study design, data extraction, data analysis, data interpretation or writing of the report.

    • Competing interests None declared.

    • Ethics approval Ethics Committee of the University Hospitals Leuven.

    • Provenance and peer review Not commissioned; externally peer reviewed.

    • Data sharing statement In consultation with the Ethics Committee that approved the study protocol, SPHERL data cannot be made publicly available. Reasons are that the informed consent signed by the workers did not cover data sharing and that an anonymised and deidentified data set still contains elements, which could potentially lead to the identification of participants. Only researchers affiliated with the Studies Coordinating Centre in Leuven have access to the study database. However, these researchers are willing to run analyses according to an analysis plan proposed by other investigators.