Hyperglycemia: The Metabolic Syndrome Component That Aggravates Erectile Dysfunction in Mexican Patients

Alan Espinosa-Marrón, Christian A. Quiñones-Capistrán, Aquiles Rubio-Blancas, María del Pilar Milke-García, Ricardo A. Castillejos-Molina. Division of Nutrition, National Institute of Medical Sciences and Nutrition “Salvador Zubirán”, Vasco de Quiroga 15, Sección XVI, Tlalpan, 14000. Mexico City, Mexico. Division of Urology, National Institute of Medical Sciences and Nutrition “Salvador Zubirán”, Vasco de Quiroga 15, Sección XVI, Tlalpan, 14000. Mexico City, Mexico.


Introduction
Metabolic syndrome refers to a set of multifactorial alterations that increase the risk of developing type 2 diabetes mellitus and cardiovascular disease. ( (4,5) Erectile dysfunction refers to the inability to achieve an erection as part of the multifaceted process of male sexual function. Erectile dysfunction is common among men over 50 years of age. (6) Etiological factors include anatomic, vascular, psychological, neurological, and hormonal disorders. (7) A total of 51.1% of Mexican men between 40 and 60 years of age are estimated to have changes in erectile function, 59.8% of whom are diagnosed with overt erectile dysfunction.6 Furthermore, projections have established that the worldwide population presenting with erectile dysfunction will reach 322 million cases by 2025. (6) The global prevalence of metabolic syndrome in subjects with erectile dysfunction varies between 29.4 and 79%. (8,9) Several studies have found a close association between the two alterations, (3,8,9) given that mechanisms underlying metabolic syndrome compromise the blood flow to the penis in numerous ways. (7) Specifically, an association between erectile dysfunction and hypertension, (10) type 2 diabetes mellitus, (11) cardiovascular disease and dyslipidemia, (12) and obesity and central adiposity has been described. (13) Recent studies performed on a Mexican population have confirmed that the lack of glycemic control in patients with type 2 diabetes mellitus increases the risk of developing erectile dysfunction. (14) Despite the publication of many studies on the relation of the different components of metabolic syndrome to erectile dysfunction, (3,5,15) the topic has not been thoroughly explored in the Mexican population, nor have the specific components of that syndrome been emphasized or identified as the most commonly associated with erectile dysfunction, its progression, and its severity. Our main objective was to analyze the relationship between metabolic syndrome and erectile dysfunction in a group of Mexican patients. Our secondary aims were to study the influence of other morbidity factors on erectile dysfunction and to define the specific metabolic syndrome components most strongly associated with erectile dysfunction severity and progression.

Materials and Methods Design
An observational, cross-sectional study was conducted on a group of men (30-60 years of age) that were regularly seen at the Urology outpatient service of the Instituto Nacional

Statistical analysis
Normality tests were performed for the continuous variables. Means for independent samples were compared through the Student's t-test. A logistic regression analysis was carried out to identify the risk factors for erectile dysfunction.
A p <0.05 value was considered significant. The statistical analysis was performed using the ibm spss version 21 Statistics® Software.

Results
One hundred and twenty-six patients were initially considered. We excluded 40 candidates and the remaining 86 participants were classified into two groups, according to a positive (70.9%) or negative metabolic syndrome diagnosis, as depicted in figure 1. Clinical characteristics are compared in table 1. Significant differences in the anthropometric parameters (weight, body mass index, neck circumference, and waist circumference), laboratory values (triglycerides, total cholesterol, glucose, and glycated hemoglobin), clinical characteristics (blood pressure), and the Beck Depression Inventory score were found. However, no differences were detected in the overall International Index of Erectile Function-5 score (13.34 vs 13.76, respectively; p = 0.707) or the testosterone or estradiol values between the participants that presented with metabolic syndrome and those that did not.     (17) showed that the combined prevalence of overweight/ obesity reached 72.5% in adults (<20 years of age). Overweight/obese patients usually present with glycemic dysregulation secondary to elevated concentrations of serum-free fatty acids (induced by apoptosis of the pancreatic β-cells) and leptin and tnf-⍺ (both of which restrict insulin secretion), subsequently reducing insulin secretory capacity. (18) Méndez-Hernández et al., (19)  Our biochemical results matched those reported in a systematic review and meta-analysis by Besiroglu et al., (21) in which there was a positive association between erectile dysfunction and hyperlipidemia. In a prospective study on a cohort of men, hypercholesterolemia was found to be a long-term erectile dysfunction predictor. (24) International Index of Erectile Function-5 questionnaire, produced an odds ratio of 6.92.
In that set of patients, the prevalence of erectile dysfunction was 72% and the lack of glycemic control was observed in 80.9% of the patients. (14) Similar results were found in our study, concluding that glycated hemoglobin >5.7% and/ or fasting glucose >110 mg/dl may directly influence the severity of erectile dysfunction in patients with metabolic syndrome.
Although it is well known that erectile dysfunction is potentially caused by testosterone deficiency, hypogonadism, and age, and in addition, the long-term benefit of testosterone replacement has been addressed, (12,29)  Our study provides evidence on metabolic syndrome as a risk factor for the development and progression of erectile dysfunction that can be extrapolated to other Latin American populations. In addition to the fact that our findings partially coincide with the existing evidence, (9,15) we reinforce the hypothesis that hyperglycemia