Risk factors associated with abdominal aortic aneurysm

A population-based study with historical and current data

Wanhainen, Anders MD
Bergqvist, David MD, PhD
Boman, Kurt MD, PhD
Nilsson, Torbjörn K. MD, PhD
Rutegård, Jörgen MD, PhD
Björck, Martin MD, PhD

^aDepartment of Surgery, Uppsala University Hospital, Uppsala, Sweden
^bÖrnsköldsvik County Hospital, Uppsala, Sweden
^cDepartment of Medicine, Skellefteå County Hospital, Uppsala, Sweden
^dInstitution of Public Health and Clinical Medicine, Umeå University Hospital, Uppsala, Sweden
^eDepartment of Clinical Chemistry, Örebro University Hospital, Uppsala, Sweden
^fDepartment of Surgery, Örebro University Hospital, Uppsala, Sweden

Reprint requests: Anders Wanhainen, MD, Department of Surgery, Uppsala University Hospital, SE-371 85 Uppsala, Sweden (e-mail address: ([email protected]).

Competition of interest: none.

Supported by grants from The Co-ordinate Centre of the Northern Counties of Sweden (VISARE-NORR), the County of Västernorrlands Research and Development (FoU) Center, the Ture Stenholm's Foundation for Surgical Research, and the Swedish Research Council K2002-73X-14222-01A.

Submitted Jun 11, 2004; accepted Jan 2, 2005.

Journal of Vascular Surgery 41(3):p 390-396, March 2005.

Objectives

To define risk factors associated with the development of abdominal aortic aneurysm (AAA) in a population-based case-control study.

Material and methods

Thirty-five patients found to have AAA at screening were compared with 140 age- and sex-matched controls. Three distinct comparisons were made. Current risk factors in both cohorts were compared. Because data were also available for both cohorts from a study conducted 12 years previously, a historical comparison was made between risk factors identified at the time of this initial evaluation. A longitudinal comparison was made between historical and current risk factors.

Results

Elevated low-density-lipoprotein cholesterol, total cholesterol, and triglyceride levels 12 years before AAA screening were associated with current AAA with an odds ratio (OR) of 2.3 (95% confidence interval [CI], 1.2 to 4.4); OR, 1.9 (95% CI, 1.3 to 2.8); and OR, 1.9 (95% CI,1.2 to 3.1)/mmol/L, respectively. Current variables assessed at AAA screening that were associated with AAA were: A history of atherosclerotic disease, OR, 3.8 (95% CI, 1.7 to 8.5); having a first-degree relative with AAA, OR, 4.4 (95% CI, 1.5 to 13.0); current smoking, OR, 5.2 (95% CI, 1.6 to 16.8); high-density-lipoprotein cholesterol level, OR, 0.1 (95% CI, 0.02 to 0.7)/mmol/L; and high-sensitivity C-reactive protein (hsCRP) level, OR, 1.1 (95% CI, 1.01 to 1.2)/mg/L. Hypertension and diabetes were not associated with AAA. A significant increase of hsCRP over time (12 years) was observed in AAA patients (P = .039) but not among controls. The variables of a history of atherosclerosis, smoking, and family history of AAA appear to interact synergistically to increase the prevalence of AAA (P < .001).

Conclusion

Among traditional risk factors for atherosclerosis, some were associated with AAA and others were not, indicating complex and partly different causes. Inflammation and heredity appear to be important factors in the development of AAA.