Genetic evidence links hyperthyroidism to knee osteoarthritis.

PURPOSE: The causal relationship between hyperthyroidism and knee osteoarthritis (KOA) remains to date unknown. We aimed to examine the potential causal relationship between hyperthyroidism status and the risk of developing KOA via a bidirectional two-sample Mendelian randomization (MR) approach.

METHODS

Single-nucleotide polymorphism (SNP) data related to hyperthyroidism and KOA were obtained from a genome-wide association study (GWAS) in Europe. KOA was used as the outcome variable and hyperthyroidism was used as the exposure factor. The inverse-variance weighted (IVW) method served as the primary analytic tool and heterogeneity and pleiotropy were evaluated via sensitivity analysis.

RESULTS

The IVW method indicated that hyperthyroidism status has a causative influence on the risk of developing KOA [OR, 1.046; 95% confidence interval (CI), 1.013-1.080; P = 0.006]. No significant reverse causality was detected. Sensitivity analyses validated the robustness of these findings.

CONCLUSIONS

Hyperthyroidism status can causally increase the risk of developing KOA. This result indicated that the risk of developing KOA may be decreased by controlling hyperthyroidism.