Rising Prevalence of Unruptured Intracranial Aneurysms Over the Past Two Decades

A systematic review and meta-analysis found that the prevalence of unruptured intracranial aneurysms (UIAs) is increasing, particularly over the past two decades, and that the rise is only partly explained by improved detection of small aneurysms and population ageing. The analysis included 162 studies involving 316,131 participants and 11,822 people with UIAs; in a hypothetical reference population aged 50 years, with 50% women and no comorbidities, the estimated UIA prevalence was 3.9%. UIA prevalence was higher among people with atherosclerosis (5.5%), a positive family history of aneurysmal subarachnoid haemorrhage (aSAH) or UIA (7.9%), connective-tissue disorders (10.3%), and autosomal dominant polycystic kidney disease (ADPKD, 12.8%). Current smoking was associated with a 1.4-fold higher risk of UIA, high blood pressure with a 1.6-fold higher risk, and female sex with a 1.9-fold higher risk. Among healthy individuals undergoing MR or CT angiography, UIA prevalence increased from the 2002–2015 period to 2016–2022, from 3.7% to 6.6% overall, while the prevalence of aneurysms ≥5 mm increased from 0.7% to 1.4%. The findings suggest that factors beyond improved detection and ageing—including potentially environmental factors—may contribute to the increasing prevalence of UIAs and support further investigation of personalised screening and management strategies for groups at particularly high risk, including patients with ADPKD, a positive family history of aSAH, or connective-tissue disorders. Source: https://www.thelancet.com/