Which of the following describes a cohort study?

A cohort study is defined by its prospective nature, where a specific group of individuals, known as a cohort, is followed over time to observe outcomes related to certain exposures, behaviors, or treatments. This design allows researchers to examine how various factors influence the development of outcomes, such as diseases or health events, by comparing changes in the cohort over the defined period.

In contrast, a study focused on individuals at one point in time reflects a cross-sectional approach, which does not track changes or outcomes over time. A retrospective analysis pertains to looking back at data that has already been collected, but does not follow a cohort forward in time. Lastly, a genetic analysis comparing affected and unaffected individuals typically refers to case-control studies, rather than tracking a cohort over time. Therefore, the distinguishing feature of a cohort study is its emphasis on longitudinal data collection, highlighting the importance of tracking a group through various time points to understand outcomes effectively.