Describe the importance of the study’s findings to human health.

Epidemiology is the study of the distribution and determinants of disease in human population. To determine if a new drug is beneficial for treating a disease, a randomized controlled trial, which is an interventional study, is the gold standard of epidemiologic design. In environmental epidemiology, however, “observational” studies are the main source of epidemiologic data, i.e., people are exposed through the course of their lives rather than through an experiment.