What type of study involves placing participants into groups based on exposure and following them prospectively?

A cohort study is characterized by the grouping of participants based on their exposure status and subsequently following them over time to observe outcomes. This study design is instrumental in assessing the association between risk factors (exposures) and specific health outcomes. By starting with exposure and observing participants in a prospective manner, researchers can gather data on how these exposures may lead to the development of conditions or diseases.

In a cohort study, participants are often classified into exposed and non-exposed groups. After this classification, the study tracks these groups over time to measure outcomes, making it a powerful method for establishing causal relationships and understanding the incidence of outcomes in relation to exposures.

This method differs from other study types, such as cross-sectional studies, which analyze data at a single point in time, making them less effective in determining cause-and-effect relationships. Case-control studies typically start with outcomes and look back to find exposure history, while longitudinal studies may refer more generally to studies that follow participants over time but do not specifically involve exposure grouping as the defining characteristic of a cohort study.