No evidence of association between smoking and intracranial aneurysm growth

Smoking does not appear to carry an excess risk of the growth of intracranial aneurysms, according to the results of a meta-analysis.

Researchers performed a systematic review and meta-analysis of studies wherein observed growth of intracranial aneurysms was evaluated in relation to smoking. Multiple online databases were searched for relevant studies. Those on familial aneurysms and genetic syndromes known to increase the risk of aneurysms were excluded.

The systematic review of literature was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. The R software was used in the meta-analysis.

A total of 18 observational studies met the inclusion criteria and were included in the meta-analysis. The pooled study population comprised 3,535 patients (mean age range, 38.4–73.9 years, 74 percent female), with a total of 4,289 aneurysms. The mean follow-up period ranged from 17 to 226 months.

Pooled data showed no statistically significant association between ever-smoking status and growth of intracranial aneurysms (odds ratio [OR], 1.10, 95 percent confidence interval [CI], 0.87–1.38). The same was true for current smoking status (OR, 1.43, 95 percent CI, 0.84–2.43).

Patients who were currently smoking did not have a higher predisposition to the growth of intracranial aneurysms compared with those who had no smoking history (OR, 1.18, 95 percent CI, 0.72–1.93). The same results were observed for patients who previously smoked relative to those who had never smoked (OR, 1.46, 95 percent CI, 0.88–2.43).

The findings suggest that the mechanism by which smoking increases rupture risk might not be growth. The researchers stressed that the absence of growth over time in the setting of smoking history does not imply protection from rupture, especially in patients for whom observation is recommended.