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Cardiovascular effects among workers exposed to multiwalled carbon nanotubes
  1. Eelco Kuijpers1,2,
  2. Anjoeka Pronk1,
  3. Robert Kleemann3,
  4. Jelle Vlaanderen2,
  5. Qing Lan4,
  6. Nathaniel Rothman4,
  7. Debra Silverman4,
  8. Peter Hoet5,
  9. Lode Godderis5,6,
  10. Roel Vermeulen2
  1. 1 Risk Analysis for Products in Development, TNO, Zeist, The Netherlands
  2. 2 Division of Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
  3. 3 Metabolic Health Research, TNO, Leiden, The Netherlands
  4. 4 Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, Maryland, USA
  5. 5 Centre for Environment and Health, Katholieke Universiteit Leuven, Leuven, Belgium
  6. 6 External Service for Prevention and Protection at Work, IDEWE, Heverlee, Belgium
  1. Correspondence to Eelco Kuijpers, Risk Analysis for Products in Development, TNO, Zeist 360, The Netherlands; eelco.kuijpers{at}


Objectives The increase in production of multiwalled carbon nanotubes (MWCNTs) has led to growing concerns about health risks. In this study, we assessed the association between occupational exposure to MWCNTs and cardiovascular biomarkers.

Methods A cross-sectional study was performed among 22 workers of a company commercially producing MWCNTs (subdivided into lab personnel with low or high exposure and operators), and a gender and age-matched unexposed population (n=42). Exposure to MWCNTs and 12 cardiovascular markers were measured in participants’ blood (phase I). In a subpopulation of 13 exposed workers and six unexposed workers, these measures were repeated after 5 months (phase II). We analysed associations between MWCNT exposure and biomarkers of cardiovascular risk, adjusted for age, body mass index, sex and smoking.

Results We observed an upward trend in the concentration of endothelial damage marker intercellular adhesion molecule-1 (ICAM-1), with increasing exposure to MWCNTs in both phases. The operator category showed significantly elevated ICAM-1 geometric mean ratios (GMRs) compared with the controls (phase I: GMR=1.40, P=1.30E-3; phase II: GMR=1.37, P=0.03). The trends were significant both across worker categories (phase I: P=1.50E-3; phase II: P=0.01) and across measured GM MWCNT concentrations (phase I: P=3.00E-3; phase II: P=0.01). No consistent significant associations were found for the other cardiovascular markers.

Conclusion The associations between MWCNT exposure and ICAM-1 indicate endothelial activation and an increased inflammatory state in workers with MWCNT exposure.

  • cardiovascular effects
  • human biomarkers
  • multi-walled carbon nanotubes (mwcnts)
  • endothelial damage marker Icam-1

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  • Contributors The basic study design was developed by RV, AP and LG. Data collection, data analyses and interpretation was administered by RK, QL, DS, NR and PH. EK drafted the manuscript and was responsible for statistical analyses, supported with feedback from AP, RV, and JV on choice of statistical methods and output. All authors were involved in the interpretation of data and have critically revised the manuscript and approved the final version.

  • Funding This work was partly supported by NanoNextNL, a micro and nanotechnology consortium of the government of The Netherlands and 130 partners. In addition, this project was partly supported by the National Institutes of Health intramural research programme.

  • Competing interests None declared.

  • Ethics approval The study was approved by the Commission for Medical Ethics of UZ Leuven (reference number S54607).

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