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OBJECTIVE: A significant reduction in the incidence of cardiovascular disease, including abdominal aortic aneurysm (AAA), has been observed in the past decades. In this study, a small but geographically well defined and carefully characterized population, previously screened for AAA and risk factors, was re-examined 11 years later. The aim was to study the reduction of AAA prevalence and associated factors.

METHODS: All men and women aged 65 to 75 years living in the Norsjö municipality in northern Sweden in January 2010 were invited to an ultrasound examination of the abdominal aorta, registration of body parameters and cardiovascular risk factors, and blood sampling. An AAA was defined as an infrarenal aortic diameter ≥30 mm. Results were compared with a corresponding investigation conducted in 1999 in the same region.

RESULTS: A total of 602 subjects were invited, of whom 540 (90%) accepted. In 2010, the AAA prevalence was 5.7% (95% confidence interval [CI], 2.8%-8.5%) among men compared with 16.9% (95% CI, 12.3%-21.6%) in 1999 (P < .001). The corresponding figure for women was 1.1% (95% CI, 0.0%-2.4%) vs 3.5% (95% CI, 1.2%-5.8%; P = .080). A low prevalence of smoking was observed in 2010 as well as in 1999, with only 13% and 10% current smokers, respectively (P = .16). Treatment for hypertension was significantly more common in 2010 (58% vs 44%; P < .001). Statins increased in the population (34% in 2010 vs 3% in 1999; P < .001), and the lipid profile in women had improved significantly between 1999 and 2010.

CONCLUSIONS: A highly significant reduction in AAA prevalence was observed during 11 years in Norsjö. Treatment for hypertension and with statins was more frequent, whereas smoking habits remained low. This indicates that smoking is not the only driver behind AAA occurrence and that lifestyle changes and treatment of cardiovascular risk factors may play an equally important role in the observed recent decline in AAA prevalence.

Objective: Previous studies suggest partly different risk factor profiles of thoracic aortic aneurysms (TAAs) and abdominal aortic aneurysms (AAAs), but prospective data are scarce. The purpose of this prospective population-based case-control study was to investigate differences in risk factor profile between TAAs and AAAs.

Methods: Participants in two prospective population-based studies, the Västerbotten Intervention Project (VIP) and the Monitoring of Trends and Determinants in Cardiovascular Disease (MONICA) study, between 1986 and 2010, underwent cardiovascular risk assessments, including blood samples, oral glucose tolerance test, blood pressure readings, and a self-reported health questionnaire. All individuals who were later diagnosed with TAAs or AAAs were identified. Age, sex, and time-matched controls were selected from the same cohorts, aiming at four controls/case. Adjusted odds ratios (aORs) for potential risk factors for later diagnosis of TAAs and AAAs, respectively, were estimated by multivariate conditional logistic regression analyses.

Results: From a total of 96,196 individuals with prospectively collected data in the VIP/MONICA cohort, a total of 236 individuals with AAAs (181 men and 55 women) and 935 matched controls, and 168 individuals with TAAs (115 men and 53 women) and 662 controls were included. The average age at baseline examination was 57.0 ± 5.7 years for AAA cases and controls, and 52.1 ± 8.8 years for TAA cases and controls. Mean time between baseline examination and diagnosis of AAAs/TAAs was 12.1 and 11.7 years, respectively. There was a clear difference in risk factor profile between AAAs and TAAs. Smoking, hypertension, and coronary artery disease were significantly associated with later diagnosis of AAAs, with highest aORs for a history of smoking (aOR, 10.3; 95% confidence interval [CI], 6.3-16.8). For TAAs, hypertension was the only positive risk factor (aOR, 1.7; 95% CI, 1.1-2.7), whereas smoking was not associated. Diabetes was not associated with either AAAs or TAAs; neither was self-reported physical activity.

Conclusions: In this prospective, population-based, case-control study, risk factor profile differed between AAAs and TAAs. This suggests a partially different etiology for TAAs and AAAs.