Prevalence of unruptured intracranial aneurysms in healthy asymptomatic Japanese adults: differences in gender and age

Abstract

Background: We aimed to assess the prevalence of unruptured intracranial aneurysms (UIAs) in healthy asymptomatic adults, and investigate the differences in incidence due to gender and age in Japan.

Methods: Magnetic resonance angiography (MRA) results of healthy asymptomatic adults who underwent the procedure for examination of the brain, from April 2010 to March 2012, were retrospectively examined. Patients with a history of ruptured aneurysm and UIAs were excluded. UIAs greater than 2.0 mm in size were counted. In accordance with these criteria, 8,696 people with a mean age of 52.2±9.5 years were examined, and 37.4 % of these individuals were women.

Results: The overall prevalence of UIAs was 3.2 %. The prevalence in women was higher than that in men (4.4 % versus 2.5 %, OR, 1.81; 95% CI, 1.4 to 2.31). The prevalence increased with age in both genders. In under 49 years, the prevalence in women and men were 2.7 % and 1.9 %, respectively, with no significant differences (OR, 1.47; CI, 0.91 to 2.37). In over 50 years, the prevalence in women was higher than that in men (5.4 % versus 2.8 %, OR, 2.01; CI, 1.52–2.67). There were significant differences in the locations of UIAs by gender (P <0.001); Internal carotid artery was more frequent in women, whereas anterior cerebral artery and middle cerebral artery were more common inmen.

Conclusions: This study provides etiological data on the prevalence of UIAs in healthy asymptomatic Japanese adults, and may be useful in determining therapeutic managements for UIAs.