Abstract
BACKGROUND: The causal relationship between circulating blood cells and Osteoarthritis (OA) remains unclear. This study aimed to explore this potential relationship using a two-sample Mendelian Randomization (MR) approach. METHODS: Data from large-scale GWAS (Blood Cell Consortium and GWAS Catalog) were analyzed using two-sample MR methods, with Inverse Variance Weighting as the primary approach. A Bonferroni correction was applied for multiple testing for the two primary traits. Robustness was assessed through comprehensive sensitivity analyses for heterogeneity and pleiotropy. RESULTS: After Bonferroni correction, Genetically Predicted Hemoglobin (HGB) showed a weak genetic association consistent with a potential causal pathway for OA risk (OR = 1.004, 95% CI 1.001-1.007, p = 0.018). The association for Neutrophil (NEU) count was not statistically significant. While sensitivity analyses did not detect directional pleiotropy, significant heterogeneity was observed for the genetic instruments. CONCLUSION: This exploratory study provides preliminary genetic evidence for a statistically significant but clinically negligible MR estimate of hemoglobin in OA pathogenesis. The clinical and biological significance of this minuscule effect remains uncertain. The findings should be interpreted as hypothesis-generating, highlighting the need for further research rather than establishing a definitive causal link.