Researchers identified patients from a community health clin

Researchers identified patients from a community health clinic who came in for routine care between January and December 1988. Patients were all followed for 20 years to determine if they developed cancer; they were put into two groups at study start – those that had an x-ray during that initial 1988 visit and those that didn’t. What study type would this be?

a. Prospective cohort

b. Retrospective cohort

c. Cross-sectional

d. Case-control

e. Experimental

Solution