Cumulative Time of Cigarette Smoking Is Associated with a Greater Risk of Aneurysmal Subarachnoid Hemorrhage and Younger Age at Presentation: A Nationwide Observation Study

Abstract

Smoking is known to be associated with an increased risk of intracranial aneurysm rupture; however, the risk in smokers stratified by age, sex, and aneurysm location is not clear. A retrospective study of all aneurysmal subarachnoid hemorrhage (aSAH) cases in Australia between 2008 and 2018 was conducted. The relative risk of aSAH in smokers compared with nonsmokers was calculated on the basis of nationwide smoking statistics and was stratified according to sex, age group, and aneurysm location. Out of 12,915 aSAH patients, 3249 (25.2%) were active smokers. Across both men and women, smoking increased the risk of aSAH by 2.4× in 30- to 39-year-olds (95% CI 2.1-2.7), 2.4× in 40- to 49-year-olds (95% CI 2.2-2.7), 2.3× in 50- to 59-year-olds (95% CI 2.1-2.4), and 1.8× in 60- to 69-year-olds (95% CI 1.7-2.0) with less of an effect in smokers younger than 30 years (RR: 1.2, 95% CI 1.0-1.5) and older than 70 years (RR: 1.0, 95% CI 0.9-1.2). Compared with a nonsmoker younger than 30 years old, the relative risk of aSAH increased by an average of 7.2 for every decade spent smoking in women and an average of 4.0 for every decade spent smoking in men. Additionally, smokers were 5.2× more likely to present before 50 years of age. Smoking increased the risk of aSAH by 2-fold between the ages of 30 and 60. Smokers experienced aSAH at younger ages.