Systematic review and Meta-Analysis of Mendelian randomisation analyses of Abdominal aortic aneurysms.
Introduction
Mendelian randomisation (MR) has been suggested to be able to overcome biases of observational studies, but no meta-analysis is available on MR studies on abdominal aortic aneurysm (AAA). This systematic review and Meta-analysis examined the evidence of causal risk factors for AAA identified in MR studies.


Methods
Publicly available databases were systematically searched for MR studies that reported any causal risk factors for AAA diagnosis. Meta-analyses were performed using random effect models and reported as odds ratio (OR) and 95% confidence intervals (CI). Study quality was assessed using a modified version of Strengthening the Reporting of Mendelian Randomisation Studies (STROBE-MR) guidelines.


Results
Sixteen MR studies involving 34,050 patients with AAA and 2,205,894 controls were included. Meta-analyses suggested that one standard deviation increase in high density lipoprotein (HDL) significantly reduced (OR: 0.66, 95% CI: 0.61, 0.72) and one standard deviation increase in low density lipoprotein (LDL) significantly increased the risk (OR: 1.68, 95%, CI: 1.55, 1.82) of AAA. One standard deviation increase in triglycerides did not significantly increase the risk of AAA (OR: 1.21, 95% CI: 0.86, 1.71). Quality assessment suggested that ten and five studies were of low and moderate risk of bias respectively, with one study considered as high risk of bias.


Conclusion
This meta-analysis suggests LDL and HDL are positive and negative casual risk factors for AAA.
['Ibrahim|Muhammad|M|', 'Thanigaimani|Shivshankar|S|', 'Singh|Tejas P|TP|', 'Morris|Dylan|D|', 'Golledge|Jonathan|J|']
Abdominal aortic aneurysm Mendelian randomization Peripheral artery disease