Question: What is epidemiology?

Alex Spiers answered on 13 Nov 2019:

Epidemiology is the study of how diseases affect the health and illness of populations. Since a population is a large number of people, we use statistics to measure the health of population, and use statistical methods to find risk factors for disease.

e.g. an epidemiologist who specialises in air pollution might be interested if young people who live near roads have worse health. They might measure cognitive health and lung health, and see if there is correlation between health outcomes, and how close children live near a road. They then use mathematics how much higher the risks would be of, say, lung infections, lung cancer etc.

We can then use this information to inform public policy about health (e.g. make laws on emissions).