Martinelli 2006.

Methods	Case‐control study
Participants	105 cases/293 controls Aged < 50 years
Interventions	Combined oral contraception: current and none use
Outcomes	Ischemic stroke Events: current use 43/67, none use 62/226
Notes	Italy
Risk of bias
Bias	Authors' judgement	Support for judgement
Exposure ascertainment	High risk	COC use not objectively confirmed.
Outcome assessment	Low risk	Ischemic stroke objectively confirmed.
Follow‐up	Unclear risk	Not applicable as this was a case‐control study.
Source population	Low risk	Controls from the same source population as the cases.