Michael H. Dong MPH, DrPA, PhD readings Toxicologic Epidemiology (10th of 10 Lectures on Toxicologic Epidemiology)

Taken in the early ’90s, when desktop computers were still a luxury.

Learning Objectives Revisit the definition and scope of toxicologic epidemiology (TE). Study the arguments for the linkage between toxicology and epidemiology. Learn about the educational and career opportunities in TE. Learn about the future of TE as predicted in this series of lectures.

Performance Objectives Be able to delineate the scope of toxicologic epidemiology (TE). To outline the strengths and limitations of toxicology vs. epidemiology. To identify the institutes for formal training and places for employment. To provide sound arguments for the series’ prediction of the future of TE.

Structure of This Final Lecture of the Series Into 5 parts to facilitate discussion of toxicologic epidemiology (TE): (1) definition and scope of TE; (2) linkage between toxicology and epidemiology; (3) education in TE; (4) employment in TE; and (5) future of, and nutrients for, TE.

Scope of Toxicologic Epidemiology (I) Toxicology and epidemiology each play an important role in health risk assessment. The field is built upon the premise that most contaminants originate from materials considered essential and beneficial to a community.

Scope of Toxicologic Epidemiology (II) The field is also built up the premise that exposure to environmental contaminants is preventable. And that the exposure needs only to be potential to be of concern. Health risk assessment is the subject matter of toxicologic epidemiology.

Scope of Toxicologic Epidemiology (III) Epidemiologic methods and tools are increasingly used to identify specific environmental/occupational hazards. Risk assessment is more within the scope of epidemiology than of toxicology; this biased perspective might have to be corrected soon.

Scope of Toxicologic Epidemiology (IV) The health effects of a contaminant are relatively more static. In contrast, the community’s exposure to the contaminant is more dynamic. More objectively, it is rather difficult to determine if the role of toxicology, or that of epidemiology, that is more important to health risk assessment.

Dialectic Arguments (I) While toxicology has a longer history, epidemiology studies document the actual human health experiences. It also deals with the effects of real human exposure. Observational studies used to place less emphasis on the measure of exposure, as epidemiologists tended to be physicians in the old days.

Dialectic Arguments (II) The toxic endpoints studied by the toxicologist and the epidemiologist are largely different. Only in the case of cancer, do they both obtain the same quality of information about their endpoints. Some toxicologists contend that the principles of toxicology are a critical part of environmental epidemiology.

Dialectic Arguments (III) Epidemiologists often consider toxicologic information in formulating hypotheses. Toxicologists recognize the preeminence of well-conducted epidemiologic studies. Animal toxicologic studies are important in complementing epidemiologic results. Unlike that for epidemiologic studies, the size of the study population for normal laboratory studies is severely limited. Risk assessment is the fad since the 1980s.

Educational Opportunities (I) Doctoral program available in human exposure assessment at Rutgers Univ. Training in: sampling strategies; new measurement methods for ingestion, inhalation, and dermal exposure; chemical biological markers, etc. Students will also gain the ability to use their training in risk assessment.

Educational Opportunities (II) Yale University has the most explicit and comprehensive doctoral program in health risk assessment. Courses include: models for exposure assessment; applied risk assessment; toxicology; molecular epidemiology; environmental epidemiology; environmental chemistry; and more.

Educational Opportunities (III) Less-structured doctoral and masters degree programs in fields closely related to exposure or risk assessment are also available. In the USA, these institutes include: Johns Hopkins Univ.; Harvard Univ.; Univ. of Pittsburgh; Univ. of Michigan, etc.

Educational Opportunities (IV) Graduate programs in fields closely related to exposure/risk assessment are rather limited on the west coast of the United States. In the west, institutes with more promising programs include: UC Berkeley; Univ. of Washington; San Diego State Univ. in California.

Career Opportunities (I) Post-doctoral research at the National Exposure Research Laboratory and at the National Center for Environmental Assessment, both are part of U.S. EPA. These positions conduct research in environmental monitoring; human and ecological exposure analysis; dose- response and exposure assessment methodologies; fate of pollutants in multiple media, etc.

Career Opportunities (II) Risk-related research positions available at the Lawrence Berkeley National Laboratory, managed by UC Berkeley for the U.S. Department of Energy. Risk assessment grants were awarded recently by the U.S. Food and Drug Administration to several universities. At the Medical Univ. of South Carolina, researchers can focus on the development of risk assessment methodologies.

Recruitment of Toxicologic Epidemiologists New and old graduates can also work for the industry as regulatory scientists. Most graduate programs in exposure and risk assessment are offered through environmental health sciences divisions/ departments at schools of public health. Recruitment programs should be effective to avoid having unqualified candidates to fill the positions.

The Ideal Practice of Toxicologic Epidemiology Best qualified candidates should be hired to fill positions in risk assessment (RA). Risk management is not solely the job of a regulatory administrator. Regulatory administrators should have technical training in RA, and be there to implement/support the recommendations of their army of health scientist staff. Regulatory decisions can be decentralized.

Future of Toxicologic Epidemiology (TE) The growth rate of TE as a health science discipline is likely at its peak. The above prediction is based on the observation that many assessment methodologies and developments have been made too fast. And these assessment tools require a much larger, ever lacking database.