The association between connective tissue laxity and the risk of an abdominal aortic aneurysm

Aims: to investigate whether connective tissue laxity is associated with ab dominal aortic aneurysms (AAA). Methods: a nested case control study in a population-based screening progra mme. The presence of pes planus, scoliosis, pectus deformities, flexible au ricular cartilages and Gorling's sign were combined with the Beighton joint mobility score to form a connective tissue laxity score. The association b etween connective tissue laxity and the risk of AAA was investigated throug h a logistic regression model. Type III collagen turnover was assessed usin g a serum radio-immunoassay for type III procollagen (PIIINP). Results: data from 231 controls (aortic diameter <2.5cm) and 190 cases (AAA >2.9 cm) were analysed. Grids ratios (OX), adjusted for known confounders were 3.1 (95% CI: 1.1-8.6)for the highest group of connective tissue scores and 2.4 (95% CI: 1.0-5.4) for the middle group, compared with those with n o signs of abnormal connective tissue function. There was no difference in mean collagen turnover between cases and control s, nor between those with a stable AAA >4 cm and those with an expanding AA A. Conclusion: connective tissue laxity is associated with a higher risk of ha ving an AAA. The collagen turnover is similar in subjects with an AAA and c ontrols. Aneurysms may be associated with abnormal connective tissue rather than an increased breakdown of normal collagen.