Table 2

Impact numbers for stroke in a case-control study7

Past medical history of atrial fibrillationCigarette smoking (20+ per day)
*Derived from adjusted OR in study7; †estimated as incidence in the total population, as the risk factor is relatively uncommon.
Proportion controls exposed, Pe0.0220.061
Odds ratio, OR*5.42.9
Annual incidence in unexposed group†, Iu68.67/10000068.67/100000
Case impact number, CIN11.339.63
Population impact number, PIN1504412565
Exposed case impact number, ECIN1.231.53
Exposure impact number, EIN331767