Editing Cohort study (section)

===Nested case-control study===
{{main|Nested case-control study}}
A nested case-control study is a case control nested inside of a cohort study. The procedure begins like a normal cohort study, however, as participants develop the outcome of interest they are selected as cases. Once the cases are identified, controls are selected and matched to each case. The process for selecting and matching cases is identical to a normal case control study. An example of a [[nested case-control study]] is ''Inflammatory markers and the risk of coronary heart disease in men and women'', which was a case control analyses extracted from the [[Framingham Heart Study]] cohort.<ref name="pmid15602020">{{cite journal |last1=Pai |first1=JK |title=Inflammatory markers and the risk of coronary heart disease in men and women |journal=N. Engl. J. Med. |volume=351 |issue=25 |pages=2599–2610 |year=2004 |pmid=15602020 |doi=10.1056/NEJMoa040967 |last2=Pischon |first2=T |last3=Ma |first3=J |display-authors=3 |last4=Manson |first4=Joann E. |last5=Hankinson |first5=Susan E. |last6=Joshipura |first6=Kaumudi |last7=Curhan |first7=Gary C. |last8=Rifai |first8=Nader |last9=Cannuscio |first9=Carolyn C.|s2cid=16142059 |doi-access=free }}</ref>

Nested case-controls have the advantage of reducing the number of participants that require details follow up or diagnostic testing to assess outcome or exposure status. However, this will also reduce the power of the study, when compared to larger cohort the study population is drawn from.