HEI to launch new diesel epidemiology project

9 November 2012

The Boston, MA based Health Effects Institute (HEI) announced it will launch a diesel epidemiology project to update its 1999 assessment of the risk of lung cancer in humans from exposure to diesel emissions.

Epidemiologic studies conducted over the past 40 years provided information on the hazards associated with exposure to diesel exhaust, including the risk of lung cancer. However, there has been uncertainty about the use of such data to estimate the magnitude of lung cancer risk in humans, largely because of concerns about the reliability of exposure estimates. This was the conclusion reached in a Special Report published by HEI in 1999, Diesel Emissions and Lung Cancer: Epidemiology and Quantitative Risk Assessment, which examined the strengths and limitations of the epidemiologic studies then available and considered whether such data could be used for quantitative risk assessment (QRA).

Recently, results of several new studies examining the association between exposure to diesel emissions and lung cancer have been published. These include cohort studies of miners who worked in non-metal mines in the United States and studies of US trucking industry employees. These studies have made strong efforts to estimate exposures more precisely than was possible in the past, said the HEI. After reviewing these studies, along with other epidemiologic and toxicologic evidence, the World Health Organization’s International Agency for Research on Cancer (IARC) designated diesel exhaust as a known human carcinogen (Class 1).

As is often the case when epidemiologists attempt to estimate past exposures—said the HEI—the question remains how useful these new studies would be in estimating risk to populations in everyday, nonwork environments, a question that is key to future risk-assessment decisions. In view of the recent studies and the continuing questions, as well as in response to requests from its government and industry sponsors, HEI is launching an effort to revisit and update its 1999 assessment.

For this purpose, HEI plans to form a panel of scientists who have expertise in epidemiology and occupational health, biostatistics, emissions, and exposure assessment. The panel will be charged with the following:

• Review the findings of the 1999 HEI Special Report, Diesel Emissions and Lung Cancer: Epidemiology and Quantitative Risk Assessment.
• Review the epidemiologic studies, their data, and their exposure estimates that have recently become available and that may form the basis of QRA for diesel exhaust, and analyze such data as needed.
• Explore whether the data from these new studies enable analyses to extend exposure–response relationships to lower exposure levels, similar to those encountered in everyday, nonoccupational environments.
• Identify gaps in the available data and sources of uncertainty.
• Make recommendations about the usefulness of extending or conducting further analyses of existing data sets.
• If necessary, make recommendations for the design of new studies that would provide a stronger basis for risk assessment.

HEI expects the panel to be named this fall, with a workshop (including investigators from the original epidemiology studies and other experts) in the first half of 2013, panel deliberations throughout 2013, and final analyses and a report in 2014.

Source: HEI