Whole-body water mass and osteoarthritis: a Mendelian randomization study

This study aimed to elucidate the potential impact of whole-body water mass on osteoarthritis at the genetic prediction level through a two-sample Mendelian randomization (MR) analysis.

Using summary data from genome-wide association studies, we obtained information on whole-body water mass and various forms of osteoarthritis, including knee and hip osteoarthritis, knee osteoarthritis, and hip osteoarthritis from a large-scale genome-wide association study. MR analysis used inverse variance weighting, weighted median, MR-Egger, simple mode, and weighted estimation. Sensitivity analyses, including the MR-Egger method, MR-PRESSO, Cochran's Q-test, and leave-one-out assessment, were performed to assess the reliability of the results.

In the inverse variance weighting model, increased genetic susceptibility to whole-body water mass was significantly associated with knee and hip osteoarthritis, knee osteoarthritis, and hip osteoarthritis (OR = 1.45, 95% CI: 1.27-1.65, p = 3.24 × 10^-8; OR = 1.53, 95% CI: 1.30-1.79, p = 2.18 × 10^-7; OR = 1.25, 95% CI: 1.04-1.50, p = 0.02). These results indicate a positive causal relationship between whole-body water mass and osteoarthritis. The MR-Egger intercept and Cochran's Q-test indicated the absence of heterogeneity and horizontal pleiotropy in the analyses of whole-body water mass and knee and hip osteoarthritis, knee osteoarthritis, and hip osteoarthritis.

The MR analysis suggests a positive correlation between whole-body water mass and risk of osteoarthritis.