Pediatric specialists conduct studies designed to examine associations—usually things they have hypothesized are causally related. The studies are usually about identifying or measuring the effects of risk factors or exposures.

Researchers use some unique terms to describe the types of studies they conduct. Some of those terms are listed below:

• Epidemiologic factors: Events, characteristics, or other definable entities that have the potential to bring about a change in a health condition or other defined outcome.



• Cohort: A cohort is a group of people with a common characteristic that is studied over a period of time as part of a scientific or medical investigation.



• Cohort studies: Studies that use epidemiological methods to follow a cohort of people with a particular attribute (e.g., people born prematurely, recipients of a drug or therapy) and compare certain results with another group who don’t possess attribute.



• Clinical trial: A study with patients that’s designed to answer a specific scientific question—for example, how a certain risk factor is associated with a specific disease.



• Multi-center studies: Controlled studies in which several institutions cooperate to plan and execute assessments of certain variables and outcomes in specific patient populations—for example, a multi-center study of sleep apnea as a risk for diabetes.



• Prospective study: A study in which we enroll people initially and then follow up with them at specific later times.



• Case-control study: With this epidemiological method, we begin by identifying persons with the disease or condition we’re investigating and compare their history of known or suspected risk factors (the “cases”) with the history of similar people who’ve been exposed but don’t have the disease or condition (the “controls”).



• Cross-sectional study: A study of individuals in a population or in a representative sample to detect whether disease or other health-related variables are present at a particular time (unlike longitudinal studies which are done over a period of time).