The additive effect refers to a situation in epidemiology where the combined effect of two or more exposures is equal to the sum of their individual effects. This concept is crucial in understanding how multiple risk factors contribute to the burden of disease in a population. For instance, if exposure to Factor A increases the risk of a disease by 10% and exposure to Factor B increases it by 15%, then the additive effect would be a 25% increase in risk when both factors are present.
