Two types of aneurysms are abdominal aortic aneurysms (AAAs) and cerebral (or brain) aneurysms. Brain aneurysms appear in 3.2% of the world population, and, in the United States, AAAs form in approximately 200,000 people per year. An aneurysm develops when a part of the blood vessel enlarges and the vessel wall becomes fragile. Most individuals with aneurysms do not experience severe health issues; however, in rare cases, aneurysms may burst, causing the possibility for fatal internal bleeding. Women have a 60% higher risk of brain aneurysms compared to men, and formations are more common in postmenopausal women. While men have an AAA risk of four to six times higher than women, the rupture rate for women is three times higher than in men.
The exact reasons for why older women are at greater risk for brain aneurysms and AAA rupture than their male counterparts are unclear. One theory suggests that estrogen production prevents the elimination of collagen in blood vessels, and recent studies have found that estrogen protects blood vessels from bulging. Another hypothesis still being investigated found that estrogen levels also correlate with reduced inflammation. Consequently, as women age and enter menopause, falling estrogen levels and accompanying decreased collagen and increased inflammation leave them more vulnerable to aneurysms.
Abdominal pain is one of the symptoms of an enlarged AAA.
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Another factor contributing to increased rupture rates in women is the deeply inadequate representation of women in AAA clinical trials. In a Northwestern study measuring aorta diameters across various ages and sexes, researchers discovered that on average, women have smaller aortas than men. However, current medical guidance relies on aorta size (using a standard measured based on trials consisting of mostly men) to determine when AAA repair is necessary. Consequently, many women are treated at a later state for AAAs than their male counterparts, introducing additional age-related health problems and larger aneurysms.
Similarly, in 2005, the U.S. Preventive Services Task Force (USPSTF) recommended AAA screenings for 65- to 75-year-old men who have smoked, but recommended against routine screening for women. The data used to construct the recommendations largely came from the Multicentre Aneurysm Screening Study (MASS), which only evaluated screenings from men. USPSTF recommendations updated as recently as 2019 still state that “evidence is insufficient” to set screening recommendations for 65- to 75-year-old women who have smoked.
However, efforts are being made to bring gender parity to aneurysm screening. For example, a promising study by Dr. DeRubertis’ team included numerous female participants, focused on specific sex and age differences, and concluded that certain women should consider AAA screening.
Still, the lack of clinical trials involving women leaves data concerning AAA incomplete, and guidelines for preventive care remain dangerously vague. To adequately protect women’s health, more comprehensive data collection is still urgently needed.
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