Causal relationship between varicose veins and hydrocele: A bidirectional two-sample Mendelian randomization study

This study aimed to investigate the causal relationship between varicose veins and hydroceles.

Genetic data for varicose veins and hydroceles were extracted from a Genome-Wide Association Study (GWAS). A total of 22,037 cases of varicose veins and 2634 cases of hydroceles were included for Mendelian randomization analysis. Inverse variance-weighted (IVW) analysis was employed as the primary method, with weighted median and MR-Egger analyses were used for supplementary validation. Several sensitivity analyses were performed to further assess the results.

The IVW analysis of varicose veins on hydroceles revealed an odds ratio (OR) of 1.117 (95% confidence interval (CI), 1.009-1.236; P = 0.014). Conversely, the IVW analysis of hydroceles on varicose veins showed an OR of 0.983 (95% CI, 0.944-1.025; P = 0.330). Heterogeneity and pleiotropy were negative in the bidirectional analysis.

This study suggests that varicose veins may be a risk factor for hydroceles. However, there is no evidence to support hydroceles as a causal risk factor for varicose veins. Our findings provide genetic evidence for the potential role of varicose veins as a risk factor for hydroceles, offering new insights for clinical practice. By establishing the causal relationship, high-risk patients can be identified, allowing for early surveillance of hydrocele presence to facilitate timely intervention and optimized treatment strategies. A statistically significant causal relationship between varicose veins and hydroceles was found, whereas hydroceles did not exert a causal impact on varicose veins.