Relationship between metabolic syndrome and erectile dysfunction
M. I. Gndüz, B. H. Gümüs, C. Sekuri
Department of Urology, Celal Bayar University, Manisa, Turkey
Asian J Androl 2004 Dec; 6: 355-358
Keywords: erectile dysfunction; metabolic syndrome; dyslipidemia; body mass index
Aim: To determine the relationship between metabolic syndrome (MS) and erectile dysfunction (ED) and to see which risk factors correlated the best with ED. Methods: Seventy-nine cardiology clinic outpatients with coronary artery disease (CAD) and lipid metabolism disorder were recruited. They were categorized as having MS, hypertension (blood pressure greater than 130/85 mmHg) and dyslipidemia. ED was classified based on International Index of Erectile Function scores. Patients were grouped into quartiles based on body mass index (BMI). Chi-square, Pearson's correlation and regression tests were used for statistical analysis. Results: The mean age of the patients was 56.6 years. ED was diagnosed in 59 (74.7 %) of the 79 patients. In the 38 patients with MS, all had ED. ED was not significantly correlated with cholesterol levels (P > 0.05), but was found often in patients who had both hypercholesterolemia and HT (P<0.01). Nineteen(76 %) of the 25 patients who had dyslipidemia had ED. However, ED was not significantly correlated with dyslipidemia (P > 0.05). Tweenty-two of the 23 patients who had BMI greater than 30 had ED, which was significantly more prevalent than that in those who had normal BMI (P<0.01). ED was seen in 38 of 53 smoker patients. Although ED was more prevalent in cigarette smokers, it was not significantly different from non-smokers (P>0.5). Conclusion: ED is present in a high percentage of patients with MS. Among multiple risk factors for ED, MS correlates the most highly. The next most important risk group is the patients with hypertension +hypercholestrolemia and obesity (BMI > 30).
Erectile dysfunction (ED) and cardiovascular diseases have common risk factors [1-3]. Metabolic syndrome (MS), the syndrome consisting of a disorder of lipid storage, insulin resistance and hypertension (HT), is extremely significant in the pathogenesis of cardiovascular diseases [4-8]. Individuals who have MS together with cardiovascular diseases should be examined for the presence of ED. This study investigated the relationship between MS and ED. The prevalence of ED in patients with dyslipidemia, HT, hypercholesterolemia, high body mass index (BMI) and smoking was also evaluated.
2 Materials and methods
2.1 Subjects and observations
Seventy-nine patients, aged 31 - 74 (mean 56.6) years, seen in the cardiology outpatient clinic suffering from coronary artery disease (CAD) and lipid metabolism disorder were recruited. They were categorized as having HT, dyslipidemia and MS. Dyslipedemia was defined as a lipid profile with the high density lipoprotein (HDL) under 40 mg/dL, cholesterol over 200 mg/dL and a triglyceride (TG) level of over 150 mg/dL. Patients with 3 of the following criteria were defined as having metabolic syndrome: 1) the waist circumference greater than 102 cm, 2) the fasting blood glucose greater than 110 mg/dL, 3) the systolic blood pressure greater than 130 mmHg and diastolic pressure greater than 85 mmHg, 4) the serum TG levels greater than 150 mg/dL and 5) the HDL cholesterol levels less than 40 mg/dL. A 15 item, self-administered questionnaire, the International Index of Erectile Function (IIEF), was used to assess the extent of ED. Based on answers to questions 1 - 5 and 15, ED was classified into four categories: (1) "no ED"- always or almost always able to get and keep an erection adequate for satisfactory intercourse, (2) "mild (minimal) ED"- usually able to get and keep an erection adequate for satisfactory intercourse, (3) "moderate ED"- sometimes able to get and keep an erection adequate for satisfactory intercourse and (4) "severe (complete) ED"- never able to get and keep an erection adequate for satisfactory intercourse. After a history and physical examination, lipid profiles were determined. Body mass index (BMI) was calculated and was categorized as: low (<18.5), normal (18.5 - 24.9), high (25 - 29.9) and obese (>30). Patients with previous pelvic surgery or spinal cord injury were excluded from the study.
2.2 Statistical analysis
Data were analysed using the Chi-squared test and Pearson's correlation test. Multivariate regression analysis was used to determine which risk factor was most highly correlated with ED. P<0.05 was considered significant.
ED was diagnosed in 59 (74.7 %) of the 79 patients. Of these, 27 (34.2 %) had mild, 17 (21.5 %) had moderate and 15 (19 %) had severe ED. Hypertension was present in 38 (48.1 %) and smoking in 53 (67.1 %) patients. Body mass index was 25-29.9 in 34 (43 %) and over 30 in 23 (29 %) patients. Thirty-eight patients had metabolic syndrome. Erectile dysfunction was present in all the patients with MS (Table 1). Twenty-four (75 %) of the 32 patients had cholesterol levels between 120-200 mg/dl and 35 (74.5 %) of 47 patients with cholesterol levels over 200 mg/dL had ED. ED was not found to be significantly correlated with cholesterol levels alone (P=0.586). However, ED was significantly more prevalent in those patients who had both hypercholesterolemia and HT with 23 of the 24 (96 %) patients having both hypercholesterolemia and HT had ED (P<0.05). Although 19 of the 25 patients who had dyslipidemia had ED, it was not more prevalent than in the group without dyslipidemia (P=0.545). Almost all (22 of the 23 patients) who had a BMI over 30 had ED, which was a significantly greater proportion than in the normal BMI patients (P<0.01). ED was found in 38 of 53 smokers. Although the prevalence of ED was higher in cigarette smokers, there was no statistical difference between cigarette smokers and non-smokers (P=0.280). These data are summarized in Table 2.
Table 1. Association of metabolic syndrome with ED.
Table 2. Association of risk factors with ED.
ED and CAD have many common risk factors. Both dyslipidemia and obesity are risk factors for CAD [4, 9]. Obesity is highly correlated with the presence of ED. ED is present in 95.7 % in those having a BMI>30.
Epidemiological studies show that patients with high serum cholesterol and low HDL levels are at increased risk for ED. This is consistent with the high correlation found between ED and atherosclerosis . However, we found no significant statistical correlation between cholesterol levels and ED, indicating that hypercholesterolemia per se or dyslipidemia per se is not a risk factor for ED. But we did find the combination of HT and hypercholesterolemia to be a significant risk factor for ED.
The lack of correlation between the cholesterol level and ED in our study may be related to the presence of normal cholesterol levels in previously hypercholesterolemic patients with statin medication. It was indicated that the increased risk for ED by fibrates or statins was not due to the medications, but was related to the underlying vascular pathology . In the present study also, some patients taking both fibrates and statins with normal cholesterol levels were found to have ED. Both kinds of medicines, especially fibrates, affect steroid hormone synthesis .
In MS and dyslipidemia patients, LDL production causes destruction of endogenous nitric oxide synthetase (NOS) [12, 13]. Early in the pathogenesis of athero-sclerosis, the bioavailability of NO on the endothelial surface is reduced, causing either local or circulating vasoconstrictor factors to become dominant, leading to damaged endothelium-based vasodilatation [14, 15]. Since ED was present in all of our MS patients, it is highly probable that MS is related to damage to the vascular and cavernosal endothelium.
Smoking is another factor injuring the structural and biochemical functions of the endothelial tissue [16, 17]. However, in this study, smoking was not associated with an increased prevalence of ED (P>0.05), suggesting that smoking per se is not a risk factor for ED.
In this study MS is the factor that has the strongest correlation with ED among all the metabolic disorders we examined. Fortunately, MS is a condition that is reversible by weight reduction and the control of blood sugar and blood pressure. However, there is no proof that reversing MS leads to a reduction in the incidence of ED. Also, it is not known whether MS control would lead to a decrease in ED severity [17, 18]. Short- and long-term effects of drugs used in treating MS should be investigated regarding their effect on the progression or reversal of ED .
After MS, the combination of HT with hypercho-lestrolemia and obesity were found to be the most important risk factors for ED. In this study, either dyslipidemia, hypercholesterolemia or smoking alone was not found to be a significant risk factor for ED.
Because the incidence of ED is quite high in males with CAD , these patients should be routinely screened for ED; If metabolic syndrome is found, it should be treated not only to avoid ED but also to avoid the progression of the arterial disease.
A, Kalter-Leibovici O, Kerbis Y, Tenenbaum-Koren E, Chen J, Sobol T, et
al. Prevalence and risk factors for erectile dysfunction in men with
diabetes, hypertension, or both diseases: a community survey among 1 412
Israeli men. Clin Cardiol 2003; 26: 25-30.
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