What is follow-up study?
follow-up study is A study in which individuals or populations, selected on the basis of whether they have been exposed to risk, have received a specified preventive or therapeutic procedure, or possess a certain characteristic, are followed to assess the outcome of exposure, the procedure or the effect of the characteristic, e.g. occurrence of disease.
source: A GLOSSARY OF TERMS FOR COMMUNITY HEALTH CARE AND SERVICES FOR OLDER PERSONS. World Health Organization, 2004.