Genetic liability to elevated circulating IP-10, IFNγ and SCGFβ levels in relation to thoracic aortic aneurysm: A mendelian randomization study

•This study uses mendelian randomization to explore the relationship between cytokines and thoracic aortic aneurysm (TAA).•High interferon gamma-induced protein 10, interferon gamma and stem cell growth factor beta can increase the risk of TAA.•The effects of the cytokines on TAA can be attenuated differently with adjustment for other cardiovascular risk factors.•Cytokines has the potential to serve as promising biomarkers of thoracic aortic aneurysm. Inflammation is associated with thoracic aortic aneurysm (TAA) but the effects of each circulating inflammatory factor on TAA remain unclear. In this study, we explored the relationship between circulating inflammatory factors and TAA risk using Mendelian randomization (MR) approach based on summary statistics from the latest genome-wide association study (GWAS) of 41 circulating inflammatory factors in 8293 Finns and a GWAS involving 1351 TAA cases and 18,295 controls of European ancestry. In univariable MR, higher interferon gamma-induced protein 10 (IP-10) levels, higher interferon gamma (IFNγ) levels and higher stem cell growth factor beta (SCGFβ) levels were associated with an increased risk of TAA (OR = 1.37, 95 % CI = 1.17–1.59, p = 7.42 × 10−5; OR = 1.43, 95 % CI = 1.19–1.74, p = 2.04 × 10−4; OR = 1.27, 95 % CI = 1.09–1.48, p = 2.40 × 10−3, respectively). In multivariable MR, the patterns of associations for the three cytokines remained adjusting for each other or smoking, but were attenuated differently with adjustment for other cardiovascular risk factors, especially for lipids and body mass index. Bidirectional MR approach did not identify any significant associations between cytokines and risk factors. Our results indicated that circulating cytokines may play mediation roles in the pathogenesis of TAA. Further studies are needed to determine whether these biomarkers can be used to prevent and treat TAA.