Risk Assessment Flashcards
How do cross sectional studies hamper health-related studies?
We don’t know if exposure came before the disease
What are the 4 components of risk assessment?
Hazard identification, dose-response relationship, exposure assessment, risk characterization
How are non-cancer risks determined?
By dividing the lifetime average daily dose (LADD) by the reference dose to calculate a hazard quotient.
Why are hazard quotients not used in cancer risk assessments?
Because reference doses are not available for cancer endpoints. Instead, cancer potencies (aka cancer slopes or betas) are calculated in epi or tox studies and they are multiplied by the LADD to estimate risk.
What are some uncertainties in risk assessments?
Default assumptions may be flawed
High dose tox studies extrapolated to lower dose (real world) scenarios
Epi data from observational studies where causality is hard to establish
Cancer slopes assume linear risks at low doses (extrapolated from high doses) and do not account for other mechanisms such as thresholds or triggers of exposure.
Define an NOAEL and how it is established.
No observed adverse effects levels. Established typically using animal but also human studies. The most sensitive effect (i.e., the effect observed at the lowest dose) it typically used to establish the NOAEL. Below the NOAEL, not effect is observed.
How are reference doses calculated?
The NOAEL value divided by several uncertainty (or safety) factors to account for species differences, population heterogeneity, adult to children, etc.
How is risk quantified?
as a probability with much uncertainty typically contained within the number (e.g., 1 in 10-6)
List several barriers to risk communication.
uncertainty, distrust, filtering of information, psychosocial factor
Can we have risk without having exposure?
No! No exposure, no risk!
