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Issues in Developing Worker Epidemiological Studies Related to Engineered Nanoparticles Are Discussed in Paper


NIOSH Update:

Contact: Fred Blosser (202) 245-0645
February 27, 2009

Scientists from the National Institute for Occupational Safety and Health (NIOSH) and a colleague from Emory University identify issues that researchers will need to consider in designing sound epidemiological studies of workers who may be exposed to engineered nanoparticles in the manufacturing and commercial use of nanomaterials.

The issues are described and discussed in a paper published on-line, ahead of print, on Feb. 21 by the Journal of Occupational and Environmental Medicine. The JOEM citation is 10.1097/JOM.0b013e3181990c2c.

Epidemiological studies are designed to identify higher-than-expected incidence of illnesses among populations of people. In occupational health, they are key for determining if adverse health effects are associated with specific work-related exposures. Such studies will be critical for determining if engineered nanoparticles pose health risks for exposed workers, the researchers note in their paper. Engineered nanoparticles are particles at the nanoscale that are intentionally produced according to explicit specifications, in order to serve particular purposes.

Even though the fundamental principles of epidemiology can be applied to engineered nanoparticles, researchers will face challenges typically not encountered in studies involving traditional materials, the paper suggests. These challenges relate to the unique characteristics and properties of engineered nanomaterials, the relative newness of nanotechnology, and the fact that nanotechnology is not an industry in itself, but a process that may involve different industry sectors and occupational groups.

To provide reliable results, studies will have to take those differences into account, the paper suggests.

Although it may be too soon to begin epidemiological studies, given current gaps in data on which such studies must build, it is not too early to identify issues pertinent to the design of studies, and to prepare strategies to address those issues, the paper suggests.

The scientists note that a dozen factors would influence the design of an epidemiological study. Among those factors, it will be particularly important to account for:

  • Heterogeneity (the chemical and physical diversity of engineered nanoparticles)
  • Temporal factors (the challenge that nanotechnology, generally, has not been in use for the
    length of time it may take for some diseases to become apparent)
  • Disease endpoints (determining what diseases or symptoms to look for on the basis of
    limited research evidence)
  • Exposure characterization (determining what to measure and how to measure it)
  • Study population (finding a group of workers for a study who have been exposed to the
    same type of engineered nanoparticle at levels high enough and for a long enough time
    to provide scientifically reliable and comparable results).

According to the paper, issues to be considered also should include the challenge of confounding factors; analytical techniques; selection of intermediate biomarkers that may predict disease; informed consent, privacy, and confidentiality for workers who are recruited for studies; development of exposure registries; linkage of study findings with wider medical surveillance of exposed worker populations; and utilization of epidemiological data in quantitative risk assessments.

The paper, “Issues in the Development of Epidemiologic Studies of Workers Exposed to Engineered Nanoparticles,” was written by Paul A. Schulte, Mary Schubauer-Berigan, Charles L. Geraci, Ralph Zumwalde, and John L. McKernan of NIOSH, and Candis Mayweather of Emory.

NIOSH is the federal agency that conducts research and makes recommendations for preventing work-related injuries and illnesses. It is a recognized leader in research partnerships to help manage the occupational health and safety implications and applications of nanotechnology. Findings, recommendations, and resources from NIOSH’s strategic research program in nanotechnology are available at

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