Decreasing prevalence of abdominal aortic aneurysm and changes in cardiovascular risk factors.

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.