Study Reveals Rising Rates of Unruptured Brain Aneurysms in Healthy Adults

• The prevalence of unruptured brain aneurysms increased from 2.9% to 6.6% over the past twenty years, according to a systematic review and meta‑analysis.
• This rise is only partially explained by aging populations and advances in imaging, indicating that other, as‑yet‑unidentified risk factors may be involved.
• The authors recommend focusing screening efforts on high‑risk populations rather than conducting universal screening of all healthy adults.

Recent data show that unruptured brain aneurysms are being detected more often, a systematic review and meta‑analysis confirmed.

In studies that screened healthy individuals using MR or CT angiography, the prevalence of an unruptured intracranial aneurysm climbed from 2.9% to 6.6% over two decades, reported Nima Etminan, MD, of the University of Heidelberg in Mannheim, Germany, and his co‑authors.

After adjusting for age and sex, the prevalence ratio was 1.8 (95 % CI 1.1‑2.8) for the period 2016‑2022 compared with 2002‑2015.

The increase in unruptured aneurysms “is only partly explained by the aging of the population and improvements in vascular imaging, suggesting that other, as yet unknown (e.g., environmental) risk factors also contribute,” Etminan and colleagues wrote in Lancet Neurology.

Aneurysms were more frequently observed in women, older individuals, smokers, and people with hypertension, the researchers noted. Those with connective‑tissue disorders, a family history of aneurysmal subarachnoid hemorrhage, or autosomal dominant polycystic kidney disease also showed higher prevalence.

Unruptured brain aneurysms are often discovered incidentally during MR or CT angiography. They attracted nationwide attention last year when reality‑TV star Kim Kardashian disclosed her diagnosis. Most remain asymptomatic, but some rupture and cause aneurysmal subarachnoid hemorrhage, which can lead to early death or lasting disability.

The overall incidence of aneurysmal subarachnoid hemorrhage has fallen by roughly 40% over the last three decades, mirroring declines in smoking and hypertension. Nevertheless, “the proportion of people harboring an unruptured intracranial aneurysm — now about one in 15 healthy adults — is increasing,” Etminan and co‑authors observed.

An incidental finding of an unruptured brain aneurysm carries clinical implications, remarked Shuo Wang, MD, of Capital Medical University in Beijing, and his co‑authors in an accompanying editorial.

“Prophylactic surgical or endovascular treatment can pose procedural risks, and complications may cause net clinical harm for lesions with a low likelihood of rupture,” they noted.

“With high‑resolution imaging and AI‑assisted screening expanding rapidly, more unruptured intracranial aneurysms will be identified in future clinical practice,” the editorialists predicted.

This study “confirms hypertension and smoking as established risk factors and highlights individuals with connective‑tissue disorders as a novel high‑risk subgroup, adding to well‑known high‑risk groups such as patients with autosomal dominant polycystic kidney disease and those with a family history of aneurysmal subarachnoid hemorrhage,” Wang and colleagues added.

“Taken together, these findings support targeted screening of people at substantially increased risk of harboring an unruptured intracranial aneurysm, rather than indiscriminate screening of the general population,” they wrote.

The systematic review and meta‑analysis incorporated 162 studies and data from 316,131 participants, including 11,822 cases of unruptured intracranial aneurysm, spanning September 1955 through July 2025. Approximately half of the studies (51 %) were rated high quality, 36 % moderate quality, and 12 % poor quality.

Overall, the estimated prevalence of an unruptured intracranial aneurysm was 3.9%. Prevalence was 5.5 % among individuals with atherosclerosis, 7.9 % for those with a positive family history of aneurysmal subarachnoid hemorrhage or unruptured intracranial aneurysms, 10.3 % for persons with connective‑tissue disorders, and 12.8 % for those with autosomal dominant polycystic kidney disease.

Risk ratios were 1.4 for current smoking, 1.6 for hypertension, and 1.9 for female sex.

“Our findings warrant further investigation into the potential benefit of personalized screening and management strategies for groups at high risk of harboring unruptured intracranial aneurysms,” Etminan and colleagues concluded.

The meta‑analysis drew mainly from selected cohorts and cross‑sectional studies rather than unselected population‑based samples, the researchers acknowledged. “Nonetheless, our data from population‑based studies indicate that prevalence in such groups does not differ substantially from that observed in more selected cohorts of healthy individuals,” they noted.

“The higher prevalences observed in patients with connective‑tissue disorders cannot be generalized to every connective‑tissue disorder, as we pooled these studies due to the limited data available,” they added.

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