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Abstract Background: The aim of the present study was to determine the pathophysiological factors which cause erectile dysfunction (ED), as well as the risk factors in different age groups in Turkey.
Methods: A total of 948 patients with ED who were admitted to three andrology clinics were evaluated in terms of etiological factors. They underwent a multidisciplinary diagnostic evaluation. Erectile dysfunction was classified as primarily organic, primarily psychogenic, mixed or unknown in etiology.
Results: Psychogenic ED was diagnosed in 65.4% of the patients and organic ED was diagnosed in 34.6% of patients overall. In patients under 40 years, the rate of psychogenic ED was 83% and the rate of organic ED was 17%, but in the patients over 40 years, the rate of psychogenic ED was 40.7% and the rate of organic ED was 59.3%. The causes of organic ED were identified as arteriogenic ED, 40.5%; cavernosal factor (venogenic) ED, 10%; neurogenic ED, 12.5%; endocrinologic ED, 1.8%; mixed type ED, 11.8%; and drug induced ED, 4.5%.
Conclusion: Our data represent a higher ratio of ED in patients under 40, which are mostly psychogenic, This finding potentially results from local social and cultural differences.
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Erectile dysfunction (ED) has been defined as the inability to achieve and/or maintain erection of sufficient rigidity and duration to permit satisfactory sexual performance.1 International consultants have concluded that ED should be considered a disorder based primarily on the complaint of the patient; testing and partner reports may be used to support the diagnosis.2 Etiologically, ED is generally categorized as organic, psychogenic or mixed.3,4 In the past, it was widely believed that most cases of ED occurred due to psychological causes.5 By the improvement of the diagnostic methods and the usage of intracorporeal injection agents in the evaluation of the dynamic features of the penile vascular system, it has been accepted that most cases of ED occurred due to organic causes.6 The related literature contains many controversies regarding the etiology of ED in male patients and the factors which act in the pathophysiology of ED also show variability depending on age.7–11
The present study aims to determine the pathophysiological factors which cause the disease as well as the risk factors in different age groups.
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A total of 948 patients with ED who were admitted to the andrology clinics of two training hospitals (Sisli Etfal and Bakirkoy Training and Research Hospitals, Turkey) and a university clinic (Department of Urology, Sutcu Imam University Hospital, Turkey), were evaluated in terms of etiological factors. Patients who had scores of less than 21 according to the validated international erectile dysfunction evaluation form (IIEF5) were included in the study.12 The patients were allocated into two groups. Group 1 consisted of 526 patients younger than 40 years old and Group 2 consisted of patients aged 40 years and older.
A detailed medical and sexual history was obtained and a physical examination was performed. Clinical vascular risk factors, such as myocardial infarction or hyperlipidemia, diabetes mellitus and hypertension as well as any surgical interventions were documented. Additionally, smoking habits, alcohol consumption and the use of any drugs that might interfere with ED were recorded. Physical examination included the assessment of male secondary sex characteristics, femoral and lower extremity pulses and a focused neurological examination including perianal sensation, anal sphincter tone and bulbocavernosus reflex. Patients with abnormal responses to the basic examination were referred to a neurologist for more sophisticated testing.
Most of the patients underwent evaluation by experienced psychiatrists. No specific grading scores of the interview were used, but the evaluation focused on detailed sexual history and description of the sexual problem, as well as details of current sexual relationships, emotional stress and psychopathology.
In regard to the clinical features of the patients, Rigi-Scan (RIGISCAN Plus, Osbon Medical, London) testing for the evaluation of nocturnal erections, combined injection and stimulation tests and penile color Doppler ultrasonography for vascular impairment were used. Only a small number of patients underwent more invasive procedures, including dynamic infusion cavernosometry and cavernosography.
Laboratory tests consisted of a complete blood count, urine analysis, serum glucose or glycosylated hemoglobin (especially in patients with family history of diabetes mellitus), lipid profile, creatinine, aspartate aminotransferase, serum alanine aminotransferase, total serum testosterone and prolactin. A thyroid function profile was obtained only in men who had signs of thyroid disease. In patients with low testosterone levels, serum luteinizing hormone and follicle stimulating hormone levels were also determined.
After history taking, physical examination, psychological evaluation and laboratory testing, ED was classified as: 1, primarily organic; 2, primarily psychogenic; 3, mixed; or 4, unknown in etiology. The patients whose etiology could not be clarified even by these investigations and those who did not accept further investigation were regarded to have ED with unknown etiology.
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The average age of the patients was 48 years (range 18–72 years). Five hundred and twenty-six patients were under 40 years (average age 31.4 years) and four hundred and twenty-two were over 40 (average age 55.6 years). The cause of ED was identified as psychogenic in 620 patients (65.4%) and as organic in 328 patients (34.6%). Organic ED was 14.8% (78/536) and psychogenic ED was 85.2% (448/526) in patients under 40 years of age. On the other hand psychogenic ED was 40.7% (172/422) and organic ED was 59.3% (250/422) in patients over 40 (Table 1).
Table 1. Age distribution of patients with regard to etiology
|Etiology||Patients under 40 (%)||Patients over 40 (%)||Total (%)|
|Psychogenic ED||448 (85.2)||172 (40.7)||620 (65.4)|
|Organic ED|| 78 (14.8)||250 (59.3)||328 (34.6)|
Pathophysiological causes of organic ED were arteriogenic (peak systolic velocity, PSV, under 25 cm/sn) in 40.5%, cavernosal factors (venogenic; end-diastolic velocity, EDV, over 5 cm/sn) in 10%, neurogenic in 12.5%, endocrinologic in 1.8%, mixed type in 11.8% and drug induced in 4.5% of 328 patients. The etiological factors could not be established in 18.5% of these patients. The distributions of the pathophysiological factors in relation with the age groups are given in Table 2.
Table 2. Age and pathophysiology distribution of the patients with organic ED
|Pathophysiology||Patients under 40 (%)||Patients over 40 (%)||Total (%)|
|Arteriogenic ED||25 (32.0%)||108 (43.2%)||113 (40.5%)|
|Venogenic ED||13 (16.6%)|| 20 (8.0%)|| 33 (10.0%)|
|Neurogenic ED||10 (12.8%)|| 31 (12.4%)|| 41 (12.5%)|
|Endocrinogenic ED|| 2 (2.5%)|| 4 (1.6%)|| 6 (1.8%)|
|Drugs induced ED|| 6 (7.6%)|| 9 (3.6%)|| 15 (4.5%)|
|Mixed type ED|| 9 (11.5%)|| 30 (12.0%)|| 39 (11.8%)|
|Unknown ED||13 (16.6%)|| 48 (19.2%)|| 61 (18.5%)|
The main risk factors of organic ED were currently smoking (41.4%), diabetes mellitus (27.1%), hypertension (17.3%), hyperlipidemia (18.5%), pelvic surgery (6.4%), perineal or pelvic trauma (5.1%), spinal cord injury (4.5%) and drug consumption (Venlafaxine in 5, Paroxetine in 3 and Cloimipramine in 7 patients; 4.5%). The distribution of all the risk factors is shown in Table 3.
Table 3. The diseases and anomalies cause of organic ED
|Risk factors||No. Patients (%)|
|Diabetes mellitus|| 89 (27.1)|
|Hyperlipidaemia|| 61 (18.5)|
|Hypertension|| 57 (17.5)|
|Pelvic surgery|| 23 (7.0)|
|Pelvic and perineal trauma|| 17 (5.1)|
|Spinal-cord injury|| 15 (4.5)|
|Drugs|| 15 (4.5)|
|Hypogonadism|| 6 (1.8)|
|Peyronie's disease|| 4 (1.2)|
|Chronic renal failure|| 3 (1.0)|
|Myocardial infarctus|| 3 (1.0)|
|Cavernosal fibrosis|| 2 (>1.0)|
|Congenital penile venous anomaly|| 2 (>1.0)|
|Brain surgery|| 2 (>1.0)|
|Multiple sclerosis|| 1 (>1.0)|
|Hyperprolactinemia|| 1 (>1.0)|
|Alcoholism|| 1 (>1.0)|
|Radiotherapy|| 1 (>1.0)|
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It was believed that the psychological factors were responsible for the most of the ED cases in the 1960s and 1970s. The probable reason for this opinion was that most scientists who dealt with sexual disorders were psychiatrists. Easier identification of the psychological factors which negatively effect erectile function and the difficulties of the identification of pathophysiological factors due to the restrictive nature of the diagnostic methods played an important role in this outcome.5 After the 1980s, concomitant with the technological development and better understanding of the erectile physiology, it was claimed that organic factors were responsible for more than 80% of the ED cases.6–13 In recent years, most researchers began to believe that the organic and psychological factors coincide in the etiology of ED. However, it is very difficult to evaluate the contribution rates of organic and psychological causes in the etiology of these mixed type cases. Furthermore, we must accept that psychological factors contribute and worsen the situation afterwards in almost every organically caused ED case.
Presently, although the most of the ED cases are believed to be organic, our data show that the rate of psychological cases was higher, especially in patients aged under 40 years. It is known that organic and psychological ED rates are directly related to age. Erectile dysfunction is reported to be psychological in 13–70% of men under 40 years and organic in the 85% of the men over 50 years.9–11
Similar to the related literature,14,15 the most common pathophysiological factor was an abnormality in penile vascular structure in organic ED cases. Atherosclerotic disease was found to be responsible for approximately 40% of ED cases in men over 40 years of age.16 In cases of the risk factors of atherosclerosis such as diabetes mellitus, hypertension, hyperlipidaemia and smoking, the probability of the organic ED increases. These risk factors have been observed frequently in our patients with organic ED.
In patients with an insufficiency of the veno-occlusive mechanism, primary ED or ED at an early age can be seen.17 This fact was confirmed by our data, since the venogenic ED rate was found to be higher in patients under 40 years than in patients over 40 (16.6%vs 8.0%, respectively). Donatucci and Lue reported a 46% venogenic rate in ED patients less than 40 years old.18 We found congenital abnormality in the penile veins in only two patients. Likewise, ED can occur in local diseases, such as Peyronie's disease, penile fracture and shunt operations which destroy the veno-occlusive mechanism. The probability of alterations in the terminal nerves, endothelial damage, fibrosis and/or atrophy in the smooth muscles of corpus cavernosum was higher in patients with diabetes mellitus and atherosclerosis. Thus, venogenic type organic ED frequently occurs together with these abnormalities.19
It has been widely reported in the published literature that noticeable ED rates were observed in various neurological diseases.20 Spinal-cord injury, brain lesions and peripheral neuropathy are the most common reasons of the neurogenic ED. Injury of pudendal and cavernous nerves due to pelvic trauma and surgery can be followed by neurogenic ED. Diabetes mellitus, alcoholism and vitamin deficiency may cause neurogenic ED by creating peripheral neuropathy.17 However, neurogenic ED cases comprise only 12.5% of the organic cases in the present study. Although the effects of androgens on libido and sexual behaviors were defined well enough, their effect on the erectile mechanism is not clear.14 The frequency of the patients with endocrinopathy accompanied with ED was reported to be only 3–6%.21 It was even less (1.8%) in the current study group. One patient had hyperprolactinemia and the other patients had undergone surgical or medical castration.
Although the drugs are accepted as a reason for ED, the mechanism of this effect is still controversial.22 Eardley et al. observed that the drugs are related to the deficiency of erection in 25% patients who applied to the ED clinics.23 The negative effect of drugs was suspected in 4.5% of our cases.
The presence of erectile dysfunction remains somewhat subjective, usually reflecting the failure of a man's sexual performance to meet his personal expectations, which in turn are largely predicated upon cultural and societal factors.20 Organic etiology in the sexual failure of the elderly is almost universal. However, the higher incidence of ED in patients under 40 in Turkey, most of which are psychogenic, raises the question of circumstantial factors.24 Similar results were obtained by Aydin et al.25 The differences among geographical regions found in Turkey may reflect interregional cultural and socioeconomic differences. For example, eastern Turkey, where the prevalence of ED is the highest, is somewhat isolated by mountainous terrain and thus, the inhabitants have retained a more traditional lifestyle and lower socioeconomic status than residents of western Turkey.24
It is obvious that Turkey is a unique country in terms of culture and history, and is located on the silk-road between Europe and Asia. This specific location is also the cause of a cultural passage between these two continents. In other words, cultural heterogeneity is more prominent, which consequently affect sexual life and sexual expectations. However, the cultural and social environments of our patients seem to be more conservative. The interviews of most of the patients also support this cultural conservatism, with only few exceptions.
We believe that the cultural and social background of these patients has a great influence on the etiology of ED. Although it is beyond the scope of this study, some examples that might have deleterious effect on sexual function can be given within the context of the above-mentioned cultural structure. Many young people are married without any sexual experience, and first having intercourse after marriage is typical in Turkey, particularly in rural areas, where parents still try to check virginity by bloody sheets. Parents, together with the elderly, stay at the same flat during the first night of marriage for such initiatives. So much psychological pressure on young couples usually results in performance anxiety and some time is needed for sexual acts to be accepted as natural behaviors of young men. An ongoing, normal sexual life needs to pass this hazardous period without any abnormal inheritance. The higher ratio of psychogenic ED in the younger group in the present study possibly had some hazards in this vulnerable period that resulted in sexual dysfunction.
There are questions of the effect of social and cultural differences in the present study, where psychogenic ED incidence was higher in younger patients. The data show a higher incidence of psychogenic ED in patients under 40, which probably results from local social and cultural differences.