Minor Genetic Overlap Among Rheumatoid Arthritis, Myocardial Infarction, and Myocardial Infarction Risk Determinants

The aim of this study was to investigate whether a shared genetic susceptibility exists between individuals with rheumatoid arthritis (RA) and individuals with myocardial infarction (MI)-including major MI risk factors-and to quantify the degree of any such overlap.

Genome-wide association study (GWAS) data for individuals with RA were constructed from a sample of 26,637 Swedish patients with RA and controls without RA. For patients with MI, GWAS data were obtained from a previously published meta-analysis. Genome-wide genetic correlation was estimated via linkage disequilibrium score regression. LAVA was employed to estimate local genetic correlations in ~2,500 nonoverlapping loci, including the major histocompatibility complex. The controls without RA were used for reference panel data. We also assessed stratified estimates of both genome-wide and local genetic correlation based on subsamples of individuals with seropositive RA and those with seronegative RA. Furthermore, genome-wide genetic correlation was estimated between RA and selected cardiovascular risk factors to elucidate pleiotropic relationships.

Following quality control, our GWAS of patients with RA consisted of 25,826 individuas. Genome-wide genetic correlation between patients with RA and MI was estimated to 0.13 (95% confidence interval -0.03 to 0.29). Six regions exhibited significant local genetic correlation, though none harbored any known risk single-nucleotide polymorphisms for either of the two traits. Estimates were similar in both individuals with seropositive RA and those with seronegative RA. No statistically significant genetic correlations were observed between RA risk factors and any of the MI risk factors.

Our findings indicate that genetic overlap between patients with RA and MI is minor. Furthermore, genetic overlap between RA and MI risk factors seem unlikely to provide a major contribution to the increased risk of MI observed in patients with RA.