Could there be a relationship between blood groups and varicocele? A multicenter case-control study with a Turkish population.

Background: Although various factors contribute to the pathophysiology of varicocele, the underlying etiological causes have not yet been fully elucidated. Due to the existence of studies showing that there is a relationship between ABO blood group antigens and vascular diseases and that the risk of varicocele increases in men with various vascular diseases, this study aimed to investigate the association between ABO blood groups and varicocele.

Methods: This multicenter study involved 6466 participants. The varicocele group included 2295 patients (1799 unilateral and 496 bilateral), while the control group consisted of 4171 individuals without varicocele. All participants visited urology outpatient clinics at 8 different hospitals in Turkey between 2018 and 2023. The groups were compared in terms of demographic data and blood groups.

Results: The distribution of the blood groups in the control group and unilateral varicocele group was similar with the Turkish population. On the other hand, in bilateral varicocele group O blood group was found to be significantly lower than the control group (p = 0.0001), and non-O blood groups were found to be significantly higher than unilateral varicocele (p = 0.022) and control groups (p = 0.008).

Conclusions: In conclusion, blood groups do not increase the risk of unilateral varicocele. However, patients without blood type O had a significantly higher likelihood of bilateral varicocele compared to those with blood type O. This study highlights a potential association between ABO blood groups and the etiology of varicocele, suggesting that genetically transmitted blood group antigens may contribute to its development within a multifactorial framework.