Hypertension is the single most common risk factor for intracerebral hemorrhage (ICH), roughly doubling the odds of a brain bleed compared to people with normal blood pressure. But high blood pressure is far from the only contributor. Age, race, alcohol use, certain medications, kidney disease, genetics, and even very low cholesterol levels all play documented roles in raising ICH risk.
High Blood Pressure
Uncontrolled hypertension damages small blood vessels in the brain over time, making them stiff and prone to rupture. In a large case-control study, hypertension carried an adjusted odds ratio of 2.45 for ICH, meaning people with high blood pressure were nearly two and a half times more likely to have a brain bleed than those without it.
The risk climbs sharply in certain subgroups. People under 55 with hypertension had nearly eight times the risk of ICH. Current smokers with hypertension faced about six times the risk. And those who had stopped taking their blood pressure medication, whether on their own or with a doctor’s guidance, had roughly five times the risk compared to hypertensive patients who stayed on treatment. That last point is critical: inconsistent blood pressure management may be more dangerous than the hypertension itself.
Age and Amyloid Buildup
ICH becomes more common with age, partly because of a condition called cerebral amyloid angiopathy (CAA). In CAA, a sticky protein called beta-amyloid accumulates in the walls of small brain arteries and capillaries, weakening them over decades. CAA is the most common cause of lobar ICH (bleeding in the outer regions of the brain) in people over 65. Unlike hypertension-related bleeds, which tend to occur in deeper brain structures, CAA-related hemorrhages happen near the brain’s surface and are more likely to recur.
Race and Ethnicity
ICH does not affect all populations equally. A study of more than 31,000 California residents who survived a first brain bleed found that Black patients had a 22% higher risk of recurrence than White patients, and Asian patients had a 29% higher risk. At five years, the cumulative recurrence rate was 6.5% for Black patients and 6.7% for Asian patients, compared to 5.2% for White patients. Prior research has also shown a roughly twofold increase in the risk of a first-ever ICH among Asian populations compared to other ethnic groups. These disparities likely reflect a combination of genetic susceptibility, rates of hypertension, and differences in access to consistent medical care.
Blood Thinners
Anticoagulant medications, commonly prescribed to prevent blood clots in conditions like atrial fibrillation, increase the chance of brain bleeding. In a Spanish registry study, older-generation blood thinners like warfarin were associated with an ICH incidence of about 2.8 per 100,000 people per year. Newer direct oral anticoagulants had an incidence of roughly 0.3 per 100,000, nearly ten times lower. If you take a blood thinner, the type of medication matters significantly for your brain bleeding risk.
Alcohol and Drug Use
Heavy drinking is one of the more underappreciated risk factors. People who consumed three or more alcoholic drinks per day had brain bleeds that were about 70% larger than those in non-drinkers, and they experienced them at a much younger age (64 on average versus 75). Even two drinks per day was linked to earlier onset of brain hemorrhage. Current evidence suggests limiting alcohol to no more than three drinks per week to meaningfully protect against all types of stroke.
Cocaine and amphetamines pose a different kind of danger. These drugs cause sudden, dramatic spikes in blood pressure that can trigger a hypertensive crisis. They also damage the inner lining of blood vessels and alter how blood clots, making arteries more vulnerable to rupture. Cocaine-related brain bleeds tend to occur in deeper brain structures, particularly the basal ganglia, though they can happen anywhere. Because the blood pressure surge is abrupt and extreme, even a single use can be enough to cause a hemorrhage in a susceptible person.
Very Low Cholesterol
This one surprises many people. While high LDL cholesterol is a well-known risk factor for heart attacks and ischemic strokes (caused by clots), very low LDL cholesterol is associated with a higher risk of brain bleeds. A prospective study following over 96,000 people for nine years found that those with LDL levels below 70 mg/dL had a 65% higher risk of ICH compared to those with levels between 70 and 99 mg/dL. When LDL dropped below 50 mg/dL, the risk was 2.7 times higher. The threshold where risk became statistically significant was about 76 mg/dL. Cholesterol plays a role in maintaining the structural integrity of blood vessel walls, and extremely low levels may leave small brain arteries more fragile.
Chronic Kidney Disease
Reduced kidney function is an independent risk factor for both first-time and recurrent ICH. Patients with chronic kidney disease (defined as a filtration rate below 60) had an 81% higher rate of recurrent brain bleeds compared to patients with normal kidney function, with 8.4 events per 100 person-years versus 4.4. The relationship likely involves a combination of chronic high blood pressure, impaired blood clotting, and blood vessel damage that accumulates as kidney function declines over years.
Genetic Risk: The APOE Gene
Certain inherited gene variants increase the risk of brain bleeding, particularly the type linked to amyloid buildup. Two variants of the apolipoprotein E gene, known as ε2 and ε4, are associated with more severe amyloid deposits in brain blood vessels. In a study published in the New England Journal of Medicine, people who carried either of these variants had a 28% chance of a recurrent lobar hemorrhage within two years, compared to just 10% for those with the most common gene type (ε3/ε3). Patients with the rare ε2/ε4 combination were especially prone to early recurrence. Genetic testing is not routine after a brain bleed, but these findings help explain why some patients face a much higher risk of having another hemorrhage.
What Predicts Worse Outcomes
Beyond risk factors for having an ICH, certain features at the time of the bleed strongly predict whether someone will survive the first 30 days. Three factors stand out: the patient’s level of consciousness on arrival (measured by a standard neurological scale), the volume of blood in the brain, and the location of the bleed. Hemorrhages in the lower part of the brain, near the brainstem and cerebellum, carry more than five times the mortality risk of bleeds in other locations. Larger bleeds and lower consciousness scores both independently worsen the prognosis. These factors are why two people with the “same” type of stroke can have dramatically different outcomes.