Risk Assessment in Health Science

Study Notes

Systematic scientific characterization of potential health effects from exposure to hazardous agents or situations.
Composed of essential steps: toxicologic research, testing, and data interpretation.

Laboratory and field observations to identify adverse effects from specific agents.
Mechanistic studies in labs to enhance understanding of toxicity.
Field measurements assessing exposure levels and populations.

Hazard: An intrinsic property of an agent or situation that can cause adverse effects upon exposure.
Risk: The likelihood of adverse effects occurring under specific conditions of exposure.
Formula: RISK = HAZARD x EXPOSURE; indicates that risk arises only when exposure occurs.

Hazard Identification: Evaluate toxic effects of chemicals.
Dose-Response Information: Characterize the relationship between exposure amount and adverse effects.
Exposure Assessment: Analyze the levels, frequency, and duration of human exposure to hazards.
Risk Characterization: Estimate how often adverse effects might occur under human exposure conditions.

Structure-Activity Relationship (SAR): Examine relationships between chemical structure and biological activity, including toxicity.
Animal Bioassays: Use animal models to assess toxicity.
In Vitro Tests: Validate assays for sensitivity, specificity, and predictive value regarding toxic endpoints.
Epidemiology: Identify associations between exposure and health outcomes through various study designs:
- Cross-sectional studies: Assess risk factors and disease status.
- Cohort studies: Monitor disease development linked to exposure.
- Case-control studies: Retrospective analysis based on disease status.

Dose-Response Curve: Illustrate the relationship between substance dose and effect magnitude.
Types of curves: Linear, logarithmic, sigmoid, etc.
Increasing the dose typically increases effect until a toxic threshold is reached.

"The dose makes the poison"; the effects of substances vary by dose, requiring margin of safety evaluations.
Final goal of risk assessment is to establish conditions that mitigate risk.

Shift from animal testing to human applications requires consideration of safety factors, such as.:
- Variability in humans due to age and sex.
NOAEL: No Observed Adverse Effect Level; critical for quantifying health impacts.