Association of serum vitamin D with diagnosis and growth of abdominal aortic aneurysm

Objective We examined the associations between 25-hydroxy vitamin D (25(OH)D3) concentration and the diagnosis and growth of abdominal aortic aneurysm (AAA). Methods AAA cases and healthy controls were recruited from vascular centers or the community. A subset of participants with AAA were monitored by repeat ultrasound examination to assess AAA growth. Serum 25(OH)D3 concentration was measured using a validated mass spectrometry method and categorized into guideline-recommended cut-points after deseasonalization. The associations between deseasonalized 25(OH)D3 concentration and AAA diagnosis and growth were examined using logistic regression and linear mixed effects modeling. Results A total of 4673 participants consisting of 873 (455 controls and 418 cases) from Queensland and 3800 (3588 controls and 212 cases) from Western Australia were recruited. For every 1 standard deviation increase in 25(OH)D3 concentration, odds of AAA diagnosis was significantly reduced in both Queensland (adjusted odds ratio: 0.81; 95% confidence interval [CI]: 0.69-0.95; P = .009) and Western Australia (adjusted odds ratio: 0.80; 95% CI: 0.68-0.94; P = .005) cohorts. A subset of 310 eligible participants with small AAA from both regions were followed for a median of 4.2 (interquartile range: 2.0-5.8) years. Compared with vitamin D sufficient participants (50 to ˂75 nmol/L), annual mean AAA growth was significantly greater in those with higher vitamin D (≥75 nmol/L) (adjusted mean difference: 0.1 mm/y, 95% CI: 0.1-0.2; P < .001). Conclusions High 25(OH)D3 concentration was paradoxically associated with a lower likelihood of AAA diagnosis and faster AAA growth. Further research is needed to resolve these conflicting findings.