Question

Describe three types of associations (chance, noncausal, and causal) that are possible among exposures and health outcomes. Provide your own example(s) for each that are relevant to public health.

Answer 1

Chance -characteristics of subjects in a sample may vary from sample to sample. As a result an association between exposure and outcome, or lack thereof, therefore to decrease a chance,increase the sample

.Causal Association
Medicine is concerned with limiting or preventing disease. The search for etiology is pursued in the hope that, once the cause of a disease is found, prevention will follow. Causality is assumed when one factor is shown to contribute to the development of disease and its removal is shown to reduce the frequency of disease. This concept of causality is different from that applied in law or philosophy. In prevention, it is sufficient to identify an exposure without necessarily identifying the ultimate cause of the disease. For example, cigarette smoke has been identified as the contaminated substance that is associated with increased rates of lung and
other cancers as well as heart and respiratory diseases. It is unnecessary to identify precisely which component in the smoke is the prime offender before instituting preventive measures.

Noncausal association

Noncausal associations occur in two
ways:
1. The disease may cause the exposure (rather than the exposure causing the
disease).
2. The disease and the exposure are both associated with a third (confounding)factor, , known or unknown