Does autoimmune diseases increase the risk of frailty? A Mendelian randomization study.

ABSTRACT

Background: The causality of autoimmune diseases with frailty has not been firmly established. We conducted this Mendelian randomization (MR) study to unveil the causal associations between autoimmune diseases with frailty. Methods: A MR analyses were performed to explore the relationships between autoimmune disease and frailty, using summary genome-wide association statistics. Results: Through a comprehensive and meticulous screening process, we incorporated 46, 7, 12, 20, 5, and 53 single nucleotide polymorphisms (SNPs) as instrumental variables (IVs) for hypothyroidism, hyperthyroidism, rheumatoid arthritis (RA), type 1 diabetes (T1D), multiple sclerosis (MS), and overall autoimmune disease, respectively. Our analysis revealed that hypothyroidism (OR = 1.023, 95% CI 1.008-1.038, p = 0.0015), hyperthyroidism (OR = 1.024, 95% CI 1.004-1.045, p = 0.0163), RA (OR = 1.031, 95% CI 1.011-1.052, p = 0.0017), T1D (OR = 1.011, 95% CI 1.004-1.017, p = 0.0012), and overall autoimmune disease (OR = 1.044, 95% CI 1.028-1.061, p = 5.32*10^-8) exhibited a positive causal effect on frailty. Conversely, there may be a negative causal association between MS (OR = 0.984, 95% CI 0.977-0.992, p = 4.87*10^-5) and frailty. Cochran's Q test indicated heterogeneity among IVs derived from hypothyroidism, hyperthyroidism, T1D, and overall autoimmune diseases. The MR-Egger regression analyzes revealed an absence of horizontal pleiotropy in any of the conducted analyses. Conclusion: This study elucidates that hypothyroidism, hyperthyroidism, RA, T1D, and overall autoimmune disease were linked to an elevated risk of frailty. Conversely, MS appears to be associated with a potential decrease in the risk of frailty.