What is the difference between confounding and interaction in epidemiology?

In epidemiology, confounding occurs when an extraneous variable is associated with both the exposure and the outcome, potentially leading to a spurious association. Interaction, on the other hand, refers to a situation where the effect of the exposure on the outcome varies depending on the level of another variable. While confounding distorts the true relationship, interaction indicates that the relationship itself is modified by another factor. Both concepts are crucial for accurately interpreting epidemiological data.