Masonic Cancer Center, University of Minnesota

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Masonic Cancer Center of the University of Minnesota

what is epidemiology

Epidemiology is the science of understanding why some people get certain diseases and others don't. Epidemiology concentrates on populations, whereas clinical medicine concentrates on the individual. It is believed that diseases are not randomly distributed throughout the population, but rather that different groups of people have a higher risk of illness based on their environment, health habits, and genetics.

Epidemiologists are often referred to as medical detectives since they work together with doctors, laboratory scientists, and others to try to piece together clues that are not always apparent, but which may point to the causes of a disease.

Epidemiologists are consulted when there are acute diseases that affect a small number of people. For example, in a local food-borne illness, epidemiologists are called in to determine the point source of the outbreak and describe the extent of the illness. Epidemiologists are also responsible for uncovering large mysteries that can affect the general population. For instance, using the tools of epidemiology, the link between super-absorbent tampons and toxic shock syndrome was revealed.

What is Cancer Epidemiology?

Cancer epidemiology focuses on the causes of cancer in the population. Since cancer is believed to occur over many months or even years, understanding its causes can be complex. Often times, the cancer epidemiologist uses what is called a 'case-control' approach to study the disease. In this case, people with and without a particular cancer are identified. Interviews are usually conducted and typically focus on individual health histories and habits. Sometimes medical records are also studied to investigate areas of interest that people often have difficulty remembering. The groups with and without cancer are then compared and researchers look for patterns or trends.

A classic example how using this type of study design unraveled an important association was the link between diethylstilbestrol (DES) use during pregnancy and the later development of vaginal cancer in young women (New England Journal of Medicine 1971; 284:878-881).

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