What is Epidemiology?

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Two healthcare workers in hazard suits spray an infected area
Image: http://www.cdc.gov/24-7/pdf/epidemiology-factsheet.pdf

When you hear the word “epidemiology” you probably think about disease epidemics.  You would be only partly correct.  Epidemiology is the branch of medicine that studies patterns and causes of health problems and uses those studies and results to minimize the problems.

Does that include studying, finding the causes, and trying to control a disease epidemic?  Yes, of course.  But epidemiology is also much more.

Epidemiology studies are the core of public health science. It impacts everyone’s lives—daily. It provides the basis for understanding the causes of disease, injury, and other harmful health conditions and allows us to identify ways of preventing them.

Epidemiologists are scientists who investigate health problems in populations to improve the quality of life. They help prevent health problems that may come up in the future, and they analyze how to prevent accidents in the workplace. People use their findings to make health decisions in their lives all the time.  Every time you take the stairs instead of the elevator, when you decide you won’t smoke, or when you eat healthier foods and get immunized against a disease, you are using results of studies done by epidemiologists to make better health choices.

A female epidemiologist surveys a woman and her son in the field.
An epidemiologist in the field surveying health habits. Content Provider: CDC/Dr. Kayla Laserson. Image: http://phil.cdc.gov/phil/quicksearch.asp

Some examples of investigations an epidemiologist might study include:


  • Public health investigations studying injuries, such as increased car accidents in a population or increased homicides.
  • Infectious diseases studies to find the cause of disease and how to control the spread.
  • Non-infectious disease research to study rates of cancers, birth defects, heart disease, or strokes.
  • Studies of natural disasters and disease occurrence to find ways of predicting possible outbreaks and preventing them by addressing the risks before they occur.
  • Analyses of outbreaks of food poisonings, contaminated medications, and toxic effects of chemicals.
  • Surveys which review the effectiveness of immunizations on preventing disease.
  • Studies of rates of infections for hospital stays and the effectiveness of surgical techniques.

As you can see, epidemiology plays a critical role in your knowing about health risks and the ways that you could reduce those risks.

Simply put, epidemiologists are like health detectives. They investigate the causes of disease, illness, or injury, study the factors involved, discover who is most at risk, and find ways to treat them or reduce their occurrence.

A female scientist in protective clothing adds chemicals to small test tubes.Epidemiologists could be sent to a farming community to investigate cases of food poisoning, an inner city hospital to look for clues about cases of increasing surgical infections, or a jungle in Africa to identify a deadly pathogen (disease-causing organism). These “health detectives” also work in laboratories where they can study pathogens never seen before or work on inventing a vaccine.

Wherever they go and whatever problem they’re working on, epidemiologists use scientific methods to analyze a problem and find solutions to critical healthcare problems.