Association analysis of endothelial nitric oxide synthase G894T gene polymorphism and erectile dysfunction complaints...

Erectile dysfunction (ED) is a common disorder leading to a serious, negative impact on the quality of the patient's life. The gene encoding endothelial nitric oxide synthase (eNOS) is an interesting candidate gene for understanding the physiopathology of ED, as it is involved in the catalytic production of nitric oxide (NO), the neurotransmitter that plays a critical role in penile tumescence and erection.

To evaluate a potential association between the G894T polymorphism in the eNOS gene and ED complaints in a population-based sample in São Paulo, Brazil.

The prevalence of ED complaints was estimated according to the answer to the question "How would you describe your ability to get and keep an erection that is adequate for satisfactory intercourse?" ED was considered to be present if the response was "sometimes" or "never."

A total of 449 men were enrolled in the study and answered an eight-item questionnaire to ascertain sexual performance/ED and satisfaction. The eNOS G894T polymorphism was genotyped using a standard polymerase chain reaction method.

Univariate analysis demonstrated that ED was associated with diabetes, hypertension, sleep apnea severity, increasing age and body mass index, as well as testosterone levels (P < 0.05). Forward multiple regression models indicated that age was the only independent factor associated with ED in this population (odds ratio = 1.09; 95% CI 1.06-1.11; P < 0.0001). Genotypic and allelic analyses provided no evidence for an association between this polymorphism and the risk for ED complaints in this sample. Population stratification did not affect the association test results.

This is the first study to examine the effect of polymorphisms in the eNOS gene and the risk for ED utilizing a case-control approach in the Brazilian population. Our results do not support a major role for eNOS gene polymorphisms in ED in this population.