Genetic association of allergic diseases, serum IgE levels and osteoarthritis: a Mendelian randomization study

Abstract Objective The question of whether there is a causal relationship between allergic diseases, immunoglobulin E levels, and osteoarthritis remains unclear. This study aimed to examine the bidirectional causal association between allergic diseases, serum IgE levels, and osteoarthritis using a Mendelian randomization study approach. Methods This study utilized publicly available pooled statistics from large genome-wide association studies to assess the causal associations between allergic diseases, serum IgE levels, and osteoarthritis. The analysis employed inverse variance weighting, MR-Egger, weighted median, and weighted mode methods. Sensitivity analyses were also conducted using MR-Egger regression, Cochran's Q test, and MR-PRESSO test to ensure the reliability of the findings. Results The IVW results indicated that there was no significant causal relationship between allergic asthma and atopic dermatitis with KOA (OR = 1.02, 95% CI:0.96–1.09, P = 0.544; OR = 1.00, 95% CI:0.96–1.04, P = 0.933) and HOA (OR = 0.95, 95% CI:0.89–1.02, P = 0.127; OR = 1.00, 95% CI: 0.94–1.06, P = 0.992). Similarly, KOA and HOA did not have a causal effect on allergic asthma (OR = 1.07, 95% CI: 0.86–1.32, P = 0.553; OR = 1.04, 95% CI: 0.89–1.23, P = 0.610), atopic dermatitis (OR = 1.05, 95% CI: 0.83–1.31, P = 0.692; OR = 0.94, 95% CI: 0.83–1.05, P = 0.284), and serum IgE levels (OR 0.98, 95% CI: 0.74–1.31, P = 0.916; OR 1.15, 95% CI: 0.99–1.34, P = 0.071). However, there was a causal effect of serum IgE levels on KOA, as they were found to increase the incidence of KOA (OR = 1.05, 95% CI: 1.00-1.10, P < 0.05). On the other hand, serum IgE levels did not have a causal effect on HOA (OR = 1.01, 95% CI: 0.94–1.08, P = 0.799). Conclusions From a genetic perspective, a causal relationship between serum IgE levels and the risk of KOA was observed. However, there was no evidence of a bidirectional causality between atopic disease and OA. Furthermore, the use of MR methods did not support the existence of a causal effect of IgE levels on HOA or OA on IgE levels.