This systematic review and meta-analysis examined the prevalence of unruptured intracranial aneurysms (UIAs) across comorbidities (ADPKD, connective-tissue disorders, family history, atherosclerosis), risk factors (smoking, hypertension, sex), countries, and time periods, using studies published up to Dec 31, 2025 (316,131 participants; 11,822 with UIAs).
Estimated UIA prevalence in a reference population (age 50, 50% female, no comorbidities) was **3.9%**. Prevalence was highest in ADPKD (12.8%; adjusted PR 4.4) and connective-tissue disorders (10.3%; adjusted PR 3.9). Female sex (RR 1.9), hypertension (RR 1.6), and smoking (RR 1.4) were significant risk factors. Notably, UIA prevalence rose from 2002–2015 to 2016–2022 (adjusted PR 1.8), with large aneurysms (≥5 mm) doubling from 0.7% to 1.4%.
- High heterogeneity (significant τ²) across studies limits precision of pooled estimates. - Certainty of evidence ranged from **very low to moderate** per GRADE, meaning some estimates carry substantial uncertainty. - The observed rise in prevalence may partly reflect improved imaging detection (MRA/CTA) and population aging rather than a true increase in aneurysm formation.
Clinicians should prioritize UIA screening in patients with ADPKD, connective-tissue disorders, or a family history of aneurysmal subarachnoid hemorrhage, as these groups carry substantially elevated prevalence (up to ~13%). The rising prevalence of UIAs—especially larger ones—argues for re-examining screening protocols and personalized management strategies for high-risk individuals.
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