Prevalence of unruptured intracranial aneurysms in the Hong Kong general population and comparison with individuals with symptoms or history of cerebrovascular disease

Introduction: We aimed to estimate the prevalence of unruptured intracranial aneurysms among the general population in Hong Kong, which has not yet been determined; we also estimated its prevalence among individuals who have symptoms or history of cerebrovascular disease. Methods: This retrospective cross-sectional study included the first cerebral magnetic resonance angiography (MRA) records of Hong Kong citizens who underwent MRA in a single hospital between July 1994 and December 2009. Records were excluded for individuals with repeat examination or a personal/family history of intracranial aneurysm. The overall prevalence of unruptured intracranial aneurysms in Hong Kong was estimated from the sex-and age-specific prevalences in the General group, as well as census data regarding the sex and age composition of the Hong Kong population. Results: In total, data on 6637 individuals were included. Asymptomatic individuals were assumed to represent the general public and allocated into a General group (n=3597); the remaining individuals were allocated into a Symptom group (n=2409) or a cerebrovascular disease (CVD) group (n=707). The prevalence of unruptured intracranial aneurysms was significantly lower in the General group (176/3597, 4.9%) than in the (152/2409, 6.3%; P=0.018). The prevalences in women and men were 5.9% (107/1809) and 3.9% (69/1788), respectively, in the General group (P=0.004). These prevalences generally increased with age. The prevalences did not significantly differ between the General and CVD groups. Conclusions: The estimated overall prevalence of unruptured intracranial aneurysm in the Hong Kong population was 3.6%. The prevalence of unruptured intracranial aneurysm was significantly higher in the Symptom group than in the General group.