Introduction: Vascular etiologies are the most common risk factors for erectile dysfunction (ED). Published studies have reported the associations of GNB3 C825T polymorphism with many vascular diseases. However, there are few reports about the association between this gene polymorphism and ED.
Aim: To investigate the associations among GNB3 C825T polymorphism, ED, and related risk factors in Taiwanese subjects.
Methods: A total of 155 patients with ED and 81 healthy controls were enrolled. All men had complete clinical histories taken. The 5-item International Index of Erectile Function (IIEF-5) was used to assess erectile conditions. The GNB3 C825T polymorphisms were determined using the polymerase chain reaction-restriction fragment length polymorphism method.
Main outcome measures: Patients with ED were defined as those having an IIEF-5 of <21.
Results: Two hundred thirty-six men were enrolled with a mean (standard deviation) age of 59.0 (10.2) years. Diabetes mellitus (DM), hypertension, and age were the three most significant independent risk factors for ED in a multiple logistic regression analysis (P = 0.008, 0.003, and 0.007, respectively). The prevalence of DM, hypertension, and body mass index (BMI) was significantly higher in GNB3 825T allele (CT/TT) carriers (P = 0.023, 0.049, and 0.035, respectively). There was no significant difference of ED prevalence between T and C allele carriers (69.1% vs. 56.2%, P = 0.07). However, the T allele carriers had significantly lower IIEF-5 scores (P = 0.02) associated with an increment of the T allele number (16.4[CC] vs. 14.4[CT] vs. 13.2[TT], P = 0.04).
Conclusions: In the present study, DM, hypertension, and BMI had significant associations with GNB3 825T allele carriers. Our results failed to show a significant association of the GNB3 C825T polymorphisms with ED prevalence. However, we cannot exclude that the presence of the T allele might influence the risk for ED severity indirectly through an increased risk for some vascular diseases.