Cohort study

How it is used

Can be prospective (following people forward from now) or retrospective (using records from the past). Cohort studies measure incidence and relative risk directly, but large ones are slow and expensive. Participants are recruited and followed up.

Example sentences

1. In this cohort study, 12,000 nurses were followed for twenty years.

2. A birth cohort study can show how early-life conditions affect adult health.

Common collocations

• prospective cohort study
• retrospective cohort study
• birth cohort
• follow up a cohort
• loss to follow-up

Related terms

• case-control studyAn observational study that starts with people who have a disease (cases) and people who do not (controls), then looks back to compare their past exposures.
• observational studyA study in which researchers observe and measure people's exposures and outcomes without assigning any treatment or intervention themselves.
• relative riskThe risk of an outcome in an exposed group divided by the risk in an unexposed group; a value of 2 means the exposed group has twice the risk.
• incidenceThe number of new cases of a disease in a population during a set period, usually given as a rate such as 25 new cases per 100,000 people per year.
• exposureContact with or experience of something that may affect health, such as a germ, a chemical, tobacco smoke, a type of diet or a particular job.

More terms: Study Design

• randomized controlled trial
• cross-sectional study
• systematic review
• meta-analysis