Quantifying the association between exposures and diseases

Having conducted a specific study design, the task is then to use the information collected to provide an effect measure which quantifies the magnitude of the association between the exposure(s) of interest and the disease under study. Epidemiological studies, and in particular their subsequent analysis, are therefore aimed at quantifying the level of increased risk when exposed to a particular factor, as this chapter explains. The effect measure which can be obtained to quantify the strength of the association, varies according to the type of study conducted. Just because there is a relationship between exposure and disease (even a strong one) does not mean that the relationship is causal.