Question

Thoroughly explain the concept of dose-response and its relevance to toxicology. What is the major difference between the dose-response relationship for non-cancer causing toxic chemicals (Threshold model) and the dose response relationship for cancer causing toxic chemicals (Linear model). Why does this difference exist? List the criteria of causality and apply them to an occupational disease discussed in the course.

Answer 1

dose-response is a concept which shows the relationship between the dosage of chemical and its impact on an individual. dose-response helps to distinguish between the chemicals impact i.e., how much amount of dose is safe, hazardous or have no impact on an individual or on population.

taxicology is a branch of science that deas with the study of adverse impact of chemical on an individual. it also deals with the diagnosis and treatment of toxic chemicals.

In toxicology, dose-response relationship principle is used to check the effect of chemicals and to diagnose whether they are toxic or not for the individual or population. dose-response relationship graph helps to read the toxicity. It is an important method used in toxicology.

following are difference between carcinogenic and non-carcinogenic dose-response chemicals:

1. the dose-response relationship between carcinogenic chemicals and non-carcinogenic chemical is different.

2. there is no threshhold model for dose-response applied in case of carcinogenic chemical while non-carcinogenic chemical has threshhold model.

3. below the threshhold level, non-carcinogenic chemicals do not work while carcinogenic chemicals have been studied at very lowest level.

4. dose-response graph is curved for non-cancer toxic chemicals while it is linear for the cancer toxic level.

these difference is due to the effect of cancer causing toxin. even a very low dosage of toxin can develop the risk of cancer. it can even initiate the cancer. but the very low dosage cannot have very adverse effect in non-cancer toxin.