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longitudinal cohort study

(LON-jih-TOO-dih-nul KOH-hort STUH-dee)
A type of research study that follows large groups of people over a long time. The groups are alike in many ways but differ by a certain characteristic (for example, female nurses who smoke and those who do not smoke). A particular outcome (such as the development of lung cancer) is compared between the groups. The same people in each group are assessed many times throughout the study.
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