A multicenter case-control study found an adjusted for ICH, and analyses from the Physicians Health Study332 also found such an association, but other studies, including a pooled analysis of the ARIC and CHS cohorts, found no relationship between smoking and ICH risk.135,334 336 A meta-analysis of 32 studies estimated the RR for ischemic stroke to be 1.9 (95% CI, 1.7 2.2) for smokers versus nonsmokers, the RR for SAH to be 2.9 (95% CI, 2.5 3.5), and the RR for ICH to be 0.74 (95% CI, 0.56 0.98).335 The annual number of stroke deaths attributed to smoking in the United States is estimated to be between 21400 (with- out adjustment for potential confounding factors) and 17800 (after adjustment), which suggests that smoking contributes to From data available from the National Health Interview Survey and death certificate data for 2000 through 2004, the Centers for Disease Control and Prevention estimated that smoking resulted in an annual average of 61616 stroke deaths among men and 97681 stroke deaths among women.338 Cigarette smoking may potentiate the effects of other stroke risk factors, including SBP339 For example, a synergistic effect exists between the use of OCs and smoking on the risk of cerebral infarction. With nonsmoking, non-OC users serving as the reference group, the odds of cerebral infarc- tion were 1.3 times greater (95% CI, 0.7 2.1) for women who smoked but did not use OCs, 2.1 times greater (95% CI, 1.0 4.5) for nonsmoking OC users, and 7.2 times greater (95% CI, 3.2 16.1) for OC users who smoked.340 There was also a syn- ergistic effect of smoking and OC use on hemorrhagic stroke risk. 