Several factors increase the risk of developing an aneurysm, and the most significant ones are high blood pressure, smoking, family history, and certain genetic conditions. Some of these you can control, others you can’t. Understanding which risks apply to you can help you take meaningful steps to protect yourself, or at least know when screening makes sense.
High Blood Pressure
Hypertension is the single most common risk factor for aneurysms of all types. Blood pressure of 130/80 mm Hg or higher, sustained over months and years, gradually damages the inner lining of artery walls. That constant force makes the walls less elastic and more prone to bulging outward. When a weakened section of artery can no longer withstand the pressure inside it, an aneurysm forms.
The damage compounds over time. As the arterial lining breaks down, fats from the bloodstream collect in the damaged areas, further stiffening and weakening the vessel. This is why aneurysms are rarely found in young, healthy people. They develop slowly, often over decades, in arteries that have been under excessive strain.
Smoking
Smoking is the strongest modifiable risk factor for aortic aneurysms, and the numbers are striking. A large study using UK Biobank data found that current smokers had a 4.3 times higher risk of developing an aortic aneurysm compared to people who had never smoked. Former smokers still carried elevated risk at 1.7 times higher, even years after quitting.
Tobacco smoke damages blood vessel walls through multiple pathways. It accelerates the breakdown of structural proteins that give arteries their strength and flexibility, promotes chronic inflammation, and raises blood pressure. These effects are dose-dependent: the more you smoke and the longer you smoke, the greater the damage. Quitting does reduce your risk over time, but it doesn’t fully reset to baseline, which is why smoking history matters so much in screening decisions.
The U.S. Preventive Services Task Force recommends a one-time ultrasound screening for abdominal aortic aneurysm in men aged 65 to 75 who have ever smoked. That recommendation exists specifically because the combination of smoking history and age creates a risk profile high enough to justify routine screening.
Family History
If you have close relatives who have had an aneurysm, your own risk rises substantially. This is especially true for brain aneurysms. Among people with two or more first-degree relatives (parents, siblings, or children) who have experienced a ruptured brain aneurysm, about 25% are found to have an unruptured aneurysm when screened. That’s a remarkably high detection rate and one of the strongest justifications for preventive imaging.
Family history likely reflects a combination of shared genetics and shared environmental exposures. Even without a known genetic condition, having a first-degree relative with an aneurysm typically prompts doctors to consider imaging surveillance, particularly for brain aneurysms where rupture can be catastrophic.
Genetic and Connective Tissue Disorders
Certain inherited conditions dramatically increase aneurysm risk because they affect the structural proteins that hold blood vessel walls together. The most well-known is Marfan syndrome, where about 14% of patients have been found to have brain aneurysms on imaging. Ehlers-Danlos syndrome carries a similar burden, with roughly 11% of patients showing intracranial aneurysms. Loeys-Dietz syndrome appears to carry even higher risk: studies have found brain aneurysms in 28% to 32% of patients screened.
These conditions affect collagen and other connective tissue proteins throughout the body, which means vascular weakness isn’t limited to one location. People with these syndromes can develop aneurysms in the aorta, brain, and other arterial beds, often at younger ages than the general population. Regular imaging surveillance is a standard part of managing these conditions.
Autosomal dominant polycystic kidney disease (ADPKD) also belongs in this category. People with ADPKD develop brain aneurysms at three to five times the rate of the general population, with roughly 8% to 9% of patients affected compared to 2% to 3% in the general population.
Age and Sex
Aneurysm risk isn’t distributed evenly across demographics. Brain aneurysms are most commonly diagnosed between ages 40 and 60, while aortic aneurysms tend to appear later. Abdominal aortic aneurysms are four to five times more common in men than in women, which is why screening guidelines focus on men in the 65 to 75 age range.
Women face their own distinct pattern of risk. They are more likely than men to develop thoracic aortic aneurysms (those in the upper portion of the aorta near the chest). Women also have a higher risk of subarachnoid hemorrhage, the dangerous bleeding event that occurs when a brain aneurysm ruptures. These differences likely reflect a mix of hormonal influences, vessel size, and connective tissue composition.
High Cholesterol and Atherosclerosis
Elevated cholesterol contributes to aneurysm formation through a cycle of damage and inflammation. Cholesterol deposits build up in the inner layer of blood vessels, damaging the lining and triggering an inflammatory response. That inflammation weakens the vessel wall and, in turn, worsens the cholesterol buildup. This feedback loop between lipid accumulation and inflammation gradually degrades the structural integrity of the artery, creating conditions for an aneurysm to develop.
This mechanism is particularly relevant for abdominal aortic aneurysms, where atherosclerosis (the buildup of fatty plaque in artery walls) is commonly found alongside the aneurysm itself. Managing cholesterol through diet, exercise, or medication doesn’t just protect against heart attacks. It also helps preserve the health of your arterial walls more broadly.
Stimulant Drug Use
Cocaine use is a recognized risk factor for both the formation and rupture of brain aneurysms. The drug blocks the normal recycling of certain chemical signals in the nervous system, causing intense spikes in blood pressure and constriction of blood vessels in the brain. These sudden surges of pressure can push a weakened artery wall past its breaking point.
The risk isn’t limited to long-term users. Even occasional cocaine use can trigger a rupture in someone who already has an undetected aneurysm. Cocaine has also been linked to a higher risk of re-rupture after an initial bleed, making it especially dangerous for anyone with a history of brain aneurysm. Other stimulants that cause sharp blood pressure spikes carry similar concerns, though cocaine has the most documented evidence.
How Multiple Risk Factors Interact
In practice, aneurysms rarely develop from a single cause. A person who smokes, has high blood pressure, and carries a family history of aneurysm faces a compounded risk that is far greater than any one factor alone. The arterial damage from smoking accelerates the weakening caused by hypertension, and genetic vulnerability lowers the threshold at which that damage becomes dangerous.
The most actionable risk factors are blood pressure, smoking, and cholesterol. Controlling these won’t eliminate risk entirely, especially if you have a genetic predisposition, but they represent the clearest opportunities to slow the arterial damage that makes aneurysms possible. If you have a strong family history or a connective tissue disorder, imaging surveillance can catch aneurysms while they’re still small and manageable, long before they become emergencies.