Screening for Abdominal Aortic Aneurysms and Risk Factors in 65-Year-Old Men in Oslo, Norway

Purpose: To investigate the prevalence of and risk factors for abdominal aortic aneurysm (AAA) in 65-year-old men in Oslo, Norway. Materials and Methods: From May 2011, until September 2019, the annual population of 65 -year-old men living in Oslo were invited to an ultrasonographic screening of the abdominal aorta. Candidates received a one-time invitation by mail, including a questionnaire on possible risk factors and comorbidities. Abdominal aortic outer-to-outer diameter and ankle-brachial index were measured by the screening team. Participants were allocated into three groups: non-, sub-and aneurysmal aorta. Written information on recommended follow-up regime was given to participants with an aortic diameter >= 25 mm. Univariate and multivariate analyses of potential risk factors were performed, in addition to descriptive analyses and significance testing. Results: In total, 19,328 were invited, 13,215 men were screened, of which 12,822 accepted inclusion in the study. Aortic diameter was registered for 12,810 participants and 330 men had aortic diameter >= 30 mm, giving a prevalence of AAA of 2.6% (95% confidence interval (CI) 2.31-2.86). We identified 4 independent risk factors for AAA: smoking (OR = 3.64, 95% CI 2.90-4.58), hypertension (OR = 1.87, 95% CI 1.49-2.35), BMI >30 (OR = 1.02, 95% CI 1.00-1.03), and diabetes mellitus (OR = 0.52, 95% CI 0.35-0.79), the latter showing an inverse association with AAA growth. A subgroup of 862 men with aortic diameters 25-29 mm had a significantly higher prevalence of BMI >25, smoking and family history of AAA, compared to participants with aortic diameter <25 mm. Conclusion: Among the participants in this study, the prevalence of abdominal aortic aneurysms was 2.6%. Participants with AAA more frequently reported cardiovascular risk factors, and less frequently diabetes mellitus.