Arachidonic Acid, but Not Omega‐3 Index, Relates to the Prevalence and Progression of Abdominal Aortic Aneurysm in a Population‐Based Study of Danish Men

Abstract

Background Animal models support dietary omega‐3 fatty acids protection against abdominal aortic aneurysm ( AAA ), but clinical data are scarce. The sum of red blood cell proportions of the omega‐3 eicosapentaenoic and docosahexaenoic acids, known as omega‐3 index, is a valid surrogate for long‐term omega‐3 intake. We investigated the association between the omega‐3 index and the prevalence and progression of AAA . We also investigated associations between AAA and arachidonic acid, an omega‐6 fatty acid that is a substrate for proinflammatory lipid mediators. Methods and Results We obtained blood samples from 498 AAA patients (maximal aortic diameter ≥30 mm) within a population‐based ultrasound‐screening trial in men and from 199 age‐matched controls who screened negative. We determined the fatty acids of red blood cells by gas chromatography. During a median follow‐up of 4.85 years, 141 AAA patients reached criteria for vascular surgical repair. Participants were high consumers of omega‐3 (average omega‐3 index: 7.6%). No significant associations were found for omega‐3 index. In contrast, arachidonic acid in AAA patients was higher than in controls ( P <0.001), and individuals in the upper tertile of arachidonic acid at baseline had higher probability of having AAA (odds ratio: 1.309; 95% confidence interval, 1.021–1.678; P =0.033). AAA patients at the upper tertile of arachidonic acid at baseline had a 54% higher risk of needing surgical repair during follow‐up (hazard ratio: 1.544; 95% confidence interval, 1.127–2.114; P =0.007). Conclusions Omega‐3 index is unrelated to men with AAA from a country in which fish consumption is customarily high. Arachidonic acid is associated with AAA presence and progression. Clinical Trial Registration URL : https://www.clinicaltrials.gov . Unique identifier: NCT 00662480.