2.1 Data sources and study design
To explore the causal relationship between IMIDs and AA, we utilized
summary genetic association datasets of European ancestry for both IMIDs
and AA from the IEU OpenGWAS Database Project
(https://gwas.mrcieu.ac.uk/). The GWAS summary statistics for AA (GWAS
ID: finn-b-I9_AORTANEUR) were obtained from the FinnGen cohorts’ Aortic
aneurysm GWAS summary statistics, which included 2,825 cases and 206,541
controls with 16,380,417 SNPs
(https://r5.finngen.fi/pheno/I9_AORTANEUR). In FinnGen Release 5, the
diagnostic criteria for AA are defined in the following link
(https://r5.risteys.finngen.fi/phenocode/I9_AORTANEUR). The GWAS
datasets for IBD, CD, and UC were established by FinnGen Biobank with
the respective GWAS ID numbers of ”finn-b-K11_IBD”, ”finn-b-K11_CROHN”
and ”finn-b-K11_ULCER”. Specifically, the GWAS study related to IBD
involved 5,673 cases and 213,119 controls and was further divided into
K11_CROHN (2,056 cases and 210,300 controls) and K11_ULCER (4,320
cases and 210,300controls) endpoints. The PSO dataset, identified by the
GWAS ID ”finn-b-L12_PSORIASIS”, was also received from FinnGen Biobank
and comprises a sample size of 4,510 cases and 212,242 controls. The
GWAS datasets associated with RA and SLE were obtained from European
Bioinformatics Institute under the ID numbers ”ebi-a-GCST90013534”
(14,361 cases and 43,923 controls) (26) and ”ebi-a-GCST003156” (5,201
cases and 9,066 controls) (27), respectively. Detailed information of
these GWAS datasets are provided in Supplementary Table S1. Based on
requirements of STROBE-MR standards(28), we report the design, methods
and results analysis of this study. Schematic representation of this MR
study is presented in Figure 1A.