Epidemiologic studies of risk factors for cancer in pet dogs. Jennifer Kelsey is a well-known cancer epidemiologist from Johns Hopkins. This article appeared in a journal otherwise devoted exclusively to human epidemiology. Conclusions I. Introduction Epidemiology is the study of diseases in populations rather than in individuals.
Epidemiological studies examine factors that are associated with developing diseases.
Since entire populations usually cannot be examined, epidemiology relies on sampling smaller parts of the overall population and, using statistics, generalizing those results to everyone. For example, it is well-documented that increases in the murder rate in the United States are associated with increased ice cream sales. Actually, increases in homicides and ice cream sales are both associated with higher daytime temperatures. Please keep this example in mind when reading this or any other epidemiological study. Almost two-thirds of American households include at least one dog.