Michael H' Dong

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Epidemiology and Risk Assessment (4th of 10
Lectures onToxicologic Epidemiology)
? readings

• Michael H. Dong
• MPH, DrPA, PhD

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

• Appreciate the recent advances in epidemiology
  pertinent to health risk assessment (RA).
• Study the epidemiologic approaches to human
  exposure assessment.
• Learn about the biomarkers used in epidemiology
  as well as in RA.

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Performance Objectives

• Able to list and describe the recent advances in
  epidemiology pertinent to health risk assessment
  (RA).
• To describe the epidemiologic approaches to
  exposure assessment.
• To discuss the strengths and limitations of the
  use of biomarkers in epidemiology and in RA.

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Health Risk Perception
Health Statutes Regulations
Toxicity Studies/Data
Research Developments
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Recent Advances in Epidemiology

• Branching out from general epidemiology.
• Specialty disciplines now including
  psychosocial pharmaco- occupational
  environmental nutritional genetic molecular
  cancer epidemiology and more.

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Psychosocial Epidemiology

• Determinants of disease social psychological
  behavioral factors.
• Not directly of regulatory concern.
• But offering valuable information for health risk
  assessment.

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Pharmacoepidemiology

• Studying the use, efficacy, and safety of
  pharmaceuticals.
• Beginning to flourish in 1980s.
• Adding a new twist to the regular course of
  health risk assessment.

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Nutritional Epidemiology

• Studying the role of nutrition/ diet in the
  etiology of disease.
• Nutritional epidemiologists conducted the first
  clinical trials.
• Human and social factors affect dietary intake.

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Genetic and Molecular Epidemiology

• Actually two separate branches.
• Molecular studying with known genes.
• Genetic studying with unknown genes.
• Useful in flagging preclinical effects of
  exposure.

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Cancer Epidemiology

• Related closely to molecular and genetic
  epidemiology.
• Now more into identifying and quantifying
  nutritional and other environmental carcinogens.
• Epidemiology on cancer effects becoming more
  available for health risk assessment.

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Environmental Occu- pational Epidemiology

• Actually two separate branches.
• But both are linked together due to studying
  exposures to common toxic agents which are
  relatively more preventable.
• Occupational epidemiology tends to use biomarkers
  more.

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Clinical Trials

• Were conducted as early as 1537.
• Sometimes referred to as human intervention
  trials.
• Used to test not only treatment but also adverse
  (side) effects.
• A simplified or special version of health risk
  assessment.

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Phases of Regulatory Clinical Trials

• Preclinical a series of laboratory or animal
  studies.
• Trial Phases (I) testing for human safety (II)
  testing for efficacy (III) overall trial
  assessment.
• Postlicensing surveillance.
• Ideally should follow a double-blind
  randomization design.

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Meta-Analysis of Clinical Trial Data

• First used around 1976.
• Uses routine statistical methods on data pooled
  from various trials typically not following the
  same study protocol.
• A controversial technique unacceptable to some
  statisticians.

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Basic Epidemiologic Study Designs

• Using primarily observational data.
• Descriptive studies.
• Cohort studies.
• Case-control studies.
• Cross-sectional studies.
• Ecological studies.

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Guidance for Epidemiology Studies

• Epidemiologic study designs can be used to assess
  human exposures.
• Good epidemiology practices by International
  Society for Pharmaco-epidemiology International
  Epidemiological Association and World Health
  Organization.

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Human Exposure Basic Definition

• Human exposure to a toxic agent is defined as the
  (level of) contact of a person with the toxicant.
• Human exposures can be categorized by route of
  entry exposure source and exposure duration.

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Human Exposure Methods and Advances

• Methods direct monitoring of individuals and
  from measurement of environmental levels.
• Advances Social Readjustment Rating Scale
  Stress Process Model geographic information
  system biomarkers, etc.

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Use of Biomarkers

• Limitations low detection levels compliance
  with sample collection.
• Related to biological monitoring.
• Types of biomarkers for exposure adverse
  response susceptibility.
• Best estimate for aggregate dose.

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Criteria of Selection of Biomarkers

• Criteria availability specificity
  invasiveness persistence time-to-appearance
  intra- and interperson variability.
• Multiple factors causing biological variation in
  dose-response.

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Biomarkers Legal and Ethical Considerations

• Legal authority as barrier privacy act.
• Ethical implications concerning the subjects
  right-to-know.
• These considerations making biomarkers useful at
  a slow pace.

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Overview of Next Lecture Toxicologic Side of
Epidemiology

• Illustrating this side through use of historical
  cases.
• Epidemiologic activities might have
  initiated/dominated in these cases.
• But the toxicologic side was also there and
  critical.