After following adults without cerebral aneurysms for up to 7 years, researchers found that new cerebral aneurysms occurred at a rate of approximately 1 per 1,000 person-years. The risk was also approximately twice as high among people with a history of smoking.
This study reports the results of following 10,995 adults who underwent MRA examinations as part of brain screening at least twice, after confirming that they had no cerebral aneurysm at the initial examination. The median follow-up period was approximately 3 years, with a maximum of approximately 7 years, and 34 new cerebral aneurysms were detected during follow-up.
The incidence of new aneurysms was calculated at approximately 1 per 1,000 person-years, with a cumulative incidence of approximately 0.28%–0.30% over 3 years. Approximately 70% of the aneurysms detected were smaller than 3 mm, approximately 20% were 3–5 mm, and approximately 3 cases were 5 mm or larger. No aneurysms measuring 10 mm or more were identified.
An analysis taking smoking history and smoking intensity into account found that the incidence of new aneurysms was approximately twice as high among smokers as among non-smokers. The incidence increased with greater smoking intensity, rising by approximately 1.28 times for every additional 10 pack-years. No significant differences were observed for age, sex, hypertension or family history among the 34 cases in this study.
Unlike previous reports focusing on people who already have cerebral aneurysms, this study is distinctive in that it followed people without cerebral aneurysms over an extended period and directly assessed new occurrences. The results may serve as basic information when considering follow-up intervals and the design of screening programmes.