In a recent study published in the Journal of the American Heart Association, researchers used Mendelian randomization to evaluate the associations of modifiable lifestyle factors (smoking, coffee consumption, sleep, and physical activity) and cardiometabolic factors (BMI, glycemic traits, type 2 diabetes, systolic and diastolic blood pressure, lipids, and inflammation and kidney function markers) with risks of any (ruptured or unruptured) intracranial aneurysm and aneurysmal subarachnoid hemorrhage.

Data from several genome-wide association studies were used to gauge genetic associations with lifestyle and cardiometabolic risk factors. Genetic information from a meta-analysis conducted by the International Stroke Genetics Consortium was used to identify nearly 6,300 cases of intracranial aneurysm and nearly 4,200 cases of aneurysmal subarachnoid hemorrhage. Cases of intracranial aneurysm and subarachnoid hemorrhage were compared with more than 59,500 controls to determine genetic predisposition for aneurysms.

According to the analysis, a genetic predisposition for insomnia was associated with a 24% increased risk for intracranial aneurysm and aneurysmal subarachnoid hemorrhage. The researchers also noted that the risk for intracranial aneurysm was about three times higher for smokers versus nonsmokers and that the risk for intracranial aneurysm was almost three times higher for each 10-mmHg increase in diastolic blood pressure.

The researchers found that, in addition, there was weak evidence for associations of genetically predicted decreased physical activity, higher triglyceride levels, higher BMI, and lower low density lipoprotein cholesterol levels with higher risk of intracranial aneurysm and aneurysmal subarachnoid hemorrhage, with a 95% confidence interval overlapping the null for at least one of the outcomes. All results were consistent in sensitivity analyses. The researchers concluded that this Mendelian randomization study suggests that smoking, insomnia, and high blood pressure are major risk factors for intracranial aneurysm and aneurysmal subarachnoid hemorrhage.

In a statement, study author Susanna C. Larsson, PhD, associate professor in Cardiovascular and Nutritional Epidemiology unit at the Karolinska Institute in Stockholm, Sweden, and the unit of medical epidemiology at Uppsala University in Uppsala, Sweden, noted, "The association between insomnia and intracranial aneurysm has not been reported previously, and these findings warrant confirmation in future studies. Our research supports the thinking that risk factors that people can change or manage may impact brain aneurysms and hemorrhage risk. Once confirmed, future studies should examine ways to incorporate this knowledge into prevention programs and therapies."

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