This article is more than 5 years old. Information may no longer be current.
Ischemic stroke risk similar in men, women who smoke
Smoking cigarettes is related to similar risk for ischemic stroke among men and women, but risk for any type of stroke is 60% to 80% higher in smokers than nonsmokers of the same sex, according to results of a new meta-analysis.
Researchers examined the results of 81 international prospective cohort studies conducted from 1966 to Jan. 26, 2013, that had findings related to sex-specific effects of smoking on stroke risk. The studies covered 3,980,359 individuals (62% American) and 42,401 strokes. Studies that focused on patients with a history of CVD or other underlying disorders were not included in the analysis.
Previous research demonstrated that smoking cigarettes is associated with a more negative effect on the risk for CHD in women than men. The researchers conducted this meta-analysis to investigate whether the same sex association was true for stroke.
Smoking and increased risk
The primary endpoint of the study was fatal/nonfatal stroke, and the primary metrics were the pooled multiple-adjusted RR and RR ratio for current smokers vs. former smokers and never-smokers.
Among women, current smokers had an 83% increased risk for stroke (95% CI, 1.58-2.12) compared with nonsmokers. Among men, current smokers had a 67% increased risk (95% CI, 1.49-1.88) compared with their nonsmoking counterparts. The researchers found no difference in stroke risk in men and women younger than 65 years and their counterparts older than 65 years.
Risk for ischemic stroke was 54% higher (95% CI, 1.21-1.96) in female current smokers and 53% higher in male current smokers (95% CI, 1.28-1.82) vs. women and men who did not smoke. Risk for hemorrhagic stroke was 63% higher (95% CI, 1.21-2.19) in female current smokers and 22% higher (95% CI, 0.98-1.51) in male current smokers vs. nonsmokers. The pooled RR ratio for hemorrhagic stroke suggested an increased RR of 17% in female smokers vs. male smokers (RR ratio=1.17; 95% CI, 1.02-1.34).
The overall RR ratio suggested a similar risk for stroke associated with female smokers compared with male smokers (RR ratio=1.06; 95% CI, 0.99-1.13). However, RR ratios analyzed by region demonstrated a greater risk for stroke among female smokers in Western countries (RR ratio=1.1; 95% CI, 1.02-1.18); the same trend was not observed among female smokers in Asian countries (RR ratio=0.97; 95% CI, 0.87-1.09).
Different pathways
“These data would suggest that the sex difference in smoking-related risk for CHD is unlikely to be mediated by differences in smoking-related behavior (such as greater degree of smoke inhalation by women) because the sex effect would also be shown for stroke,” Sanne A.E. Peters, PhD, and colleagues wrote.
“Instead, it is plausible that some of the pathways mediating the relationship between smoking and coronary risk are more susceptible to the anti-oestrogenic effect of smoking than those governing the relationship between smoking and stroke risk.”
The researchers also found that “compared with never-smokers, former smokers of both sexes have a much lower risk for stroke than do current smokers.” This may indicate that “tobacco control policies that target both smoking initiation and smoking cessation should be a mainstay of stroke primary prevention programs,” they wrote.
Disclosure: The researchers report no relevant financial disclosures.