How are the results of epidemiological studies interpreted?

The results of epidemiological studies are given in terms such as relative risk for cohort studies or odds ratios for case control studies. These are statistical terms that give researchers information about the strength of any association detected between disease and exposure to the proposed risk factor.

The five main criteria for establishing a likely association are:

1. the strength of association - the relationship must be clear
2. consistency - repeatable in other study populations
3. temporality - exposure must come before the disease
4. plausibility - it must make sense biologically
5. biological gradient - dose-response relationship, more exposure equals more disease