The association of obesity with abdominal aortic aneurysm presence and growth

The importance of obesity as a risk factor for atherothrombosis has been clearly demonstrated. Abdominal aortic aneurysm (AAA) is believed to develop due to mechanisms distinct from atherosclerosis. The aim of this systematic review was to critically assess published evidence examining: (1) the association of obesity with AAA presence; (2) the association of obesity with AAA growth.

Studies investigating the association of markers of obesity with AAA were identified by searching the PUBMED database and hand searching of article reference lists. To be eligible for inclusion studies had to report a recognised measure of adiposity, i.e. body mass index, waist circumference or an imaging technique to quantify adipose distribution. AAA presence and progression also had to be reported and assessed by ultrasound or computed tomography. Eight eligible studies assessed the association of obesity with AAA presence; and two studies which assessed the association of obesity with AAA growth were included.

Of the eight studies that examined AAA presence, five studies examined body mass index (BMI) and three studies measured waist circumference (WC). Three of five studies reported that BMI was positively associated with AAA presence or increasing abdominal aortic diameter. Two of three studies reported that WC was positively associated with AAA presence or larger abdominal aortic diameter. Three of the included studies utilised secondary measures of adiposity: waist-to-hip ratio (WHR), ultrasound assessment of adiposity and bioimpedence testing. Of these, only WHR was found to have a significant positive association with AAA presence. Of the two studies assessing the association of obesity with AAA growth both reported no association between BMI and AAA progression.

The reviewed studies suggest that anthropometric measures of BMI and WC are associated with AAA presence. Currently there is no convincing data that obesity is associated with AAA growth but further studies employing more detailed anthropometric measures are needed.