Familial occurrence of abdominal aortic aneurysm

Background: A family history of abdominal aortic aneurysm has been reported to increase the risk for developing the disease. Objective: To determine the risk for abdominal aortic aneurysm in first-deg ree relatives of patients with the disease. Design: Cross-sectional ultrasonographic screening study. Setting: University Central Hospital, Helsinki, Finland. Patients: 238 of 325 living first-degree relatives of patients having surge ry for abdominal aortic aneurysm (age > 50 years; 98 men and 110 women) and 281 controls (135 men and 149 women) without a family history of abdominal aortic aneurysm. Measurements: Ultrasonography was used to measure aortic diameter in 101 ma le relatives and 140 female relatives (241 of the 325 persons at risk [74%] ) and in 281 controls. Results: Three siblings had already undergone surgery for abdominal aortic aneurysm. Eleven siblings (all brothers) (11 of 101 [10.9%]) had ultrasonog raphic evidence of abdominal aortic aneurysm (aortic diameter > 30 mm). In the control group, 2 men (1.5%) and 2 women (1.3%) had an aneurysm. Thirty siblings and no controls had dilatation of the abdominal aorta (aortic diam eter, 20 to 29 mm). Neither the age nor the sex of the proband affected ris k for developing abdominal aortic aneurysm among first-degree relatives. Fa mily history increased the risk for an aneurysm by 4.33-fold (95% CI, 1.32- fold to 14.23-fold), male sex increased the risk by 12.21-fold (CI, 2.63-fo ld to 56.64-fold), and age (by decade) increased the risk by 1.93-fold (CI, 1.15-fold to 3.25-fold). Conclusion: Aging brothers of patients with known abdominal aortic aneurysm have the highest risk for developing the disease; the prevalence of the di sease in siblings older than 60 years of age is 18%.