Mann 1976a.

Methods	Case‐control study
Participants	54 cases/54 controls Aged 40 to 44 years
Interventions	Combined oral contraception: current, past and none use
Outcomes	Fatal myocardial infarction Events: current use 10/5, past use 8/5, none use 44/45
Notes	UK
Risk of bias
Bias	Authors' judgement	Support for judgement
Exposure ascertainment	High risk	COC use not objectively confirmed.
Outcome assessment	Low risk	Myocardial infarction objectively confirmed.
Follow‐up	Unclear risk	Not applicable as this was a case‐control study.
Source population	High risk	Controls from a different source population to the cases.