From the article:
This is a unique study in that it monitored aneurysm patients over their entire lifetimes, whereas typical follow-up studies last only between one and five years in duration.
[…]
The new study established that approximately one third of all aneurysms and up to one fourth of small aneurysms will rupture during a patient’s lifetime. The risk of rupture is particularly high for female smokers with brain aneurysms of seven millimetres or more in diameter. What surprised the researchers most was that the size of an aneurysm had little impact on its risk for rupture, particularly for men, despite a previously presumed correlation. In addition, the risk of rupture among non-smoking men was exceptionally low.
“This is not to say that aneurysms in non-smoking men never rupture, but that the risk is much lower than we previously thought. This means treating every unruptured aneurysm may be unnecessary if one is discovered in a non-smoking man with low blood pressure,” Juvela clarifies.