title: Sibling risks of abdominal aortic aneurysm.
abstract: There is evidence that the risk of abdominal aortic aneurysm (AAA) is greater in first-degree relatives of patients with the disorder than in the same age group of the general population. We conducted a 3-year study of siblings of AAA probands and siblings of a control group (cataract surgery patients) of the same age. Genetic information was obtained by interview from 126 probands and 100 controls; another family member was present at the interview. Medical records were obtained and further information verified before a sibling (over age 50) was assigned affected status. Of 427 siblings of probands, 19 (4.4%) had probable or definite AAA, compared with five (1.1%) of 451 siblings of controls. The lifetime cumulative risks of AAA at age 83 were 11.7% (SD 3.1) and 7.5% (4.1), respectively. The risk of AAA began at an earlier age and increased more rapidly for probands' siblings than for controls' siblings (p < 0.01, log-rank test). A risk comparison, based on the results of ultrasound screening of 54 geographically accessible siblings of probands and the 100 controls showed a similar pattern. Ten (19%) siblings of probands and eight (8%) controls had AAA on ultrasound (lifetime cumulative risk 60.8% [18.9] vs 14.9% [5.1], p = 0.01). These results show that familial factors influence the age of onset of AAA. We recommend routine ultrasound examination of siblings of patients with AAA.
authors.affiliation: Department of Medical Genetics, University of British Columbia, Vancouver, Canada.
authors.forename: P A
authors.initials: PA
authors.lastname: Baird
authors.forename: A D
authors.initials: AD
authors.lastname: Sadovnick
authors.forename: I M
authors.initials: IM
authors.lastname: Yee
authors.forename: C W
authors.initials: CW
authors.lastname: Cole
authors.forename: L
authors.initials: L
authors.lastname: Cole
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000235:genetics*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009679:Nuclear Family; D012307:Risk Factors; D012737:Sex Factors; D014463:Ultrasonography