Erectile Dysfunction -- The Canary In The Mineshaft?

Main Category: Men's health
Also Included In: Erectile Dysfunction / Premature Ejaculation;  Cardiovascular / Cardiology;  Urology / Nephrology
Article Date: 23 May 2007 - 9:00 PST

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New research into urologic conditions - such as erectile dysfunction - indicate that these disorders could be associated with or precursors to more serious conditions, and suggest a need for practitioners to view these diseases in the greater context of total health as opposed to isolated disorders. A special session highlighting the association on urologic diseases with non-urologic conditions such as heart disease and metabolic syndrome was presented during the 102nd Annual Scientific Meeting of the American Urological Association. A special session for the media was moderated by Marshall L. Stoller, M.D.

ENDOTHELIAL DYSFUNCTION AND OXIDATIVE STRESS ASSOCIATED WITH THE METABOLIC SYNDROME CAN BE REVERSED BY A CHRONIC TREATMENT WITH SILDENAFIL (Abstract 686)

Metabolic syndrome is characterized by a number of conditions, including elevated blood pressure, excess body fat around the waist and insulin resistance. Many patients with these conditions also exhibit endothelial dysfunction with increases in oxidative stress and decreases in nitric oxide production - which has been related to erectile dysfunction (ED). Researchers from France explored whether treatment with sildenafil - a common pharmacologic treatment for ED - could improve endothelial dysfunction in a rat model.

Researchers administered sildenafil to fructose-fed rats to achieve plasma concentrations known to give efficacy in men and observed endothelial function and oxidative stress in the animals during treatment and one-week after treatment had been stopped. It was observed that chronic sildenafil treatment improved endothelial function and oxidative stress, suggesting that this treatment could be a benefit for cardiovascular indications as well as erectile dysfunction.

ERECTILE DYSFUNCTION AND CORONARY HEART DISEASE (Abstract 864)

Research has shown a connection between erectile dysfunction (ED) and cardiovascular disease (CVD) in men, and has established a need to consider one a precursor to the other. Researchers further evaluated the association of these two conditions and whether the association could be age-related.

A random sample of men from the Olmsted County population was evaluated by questionnaire, and community medical records of the subjects were examined. Logistical regression models examined the associations between ED and CVD. Men with CVD were 4.2 times more likely to have ED than men without heart disease. The results underscore a need to consider sexual function in men with heart disease and CVD in men with ED.

ERECTILE DYSFUNCTION, METABOLIC SYNDROME, HYPOGONADISM ARE INTERTWINED (Abstract 863)

If left untreated, metabolic syndrome can lead to an increased risk for diabetes mellitus and cardiovascular disease - both known risk factors for erectile dysfunction (ED). Hypogonadism, or low testosterone, is an etiological factor for metablic syndrome and an etiological factor in ED. Using a sample of men with ED, German researchers investigated symptoms and incidence of metabolic syndrome and hypogonadism.

771 erectile dysfunction patients were given comprehensive screening for symptoms of hypogonadism and metabolic syndrome over a two-year period. 18.3 percent had testosterone levels less than 12 nmol/L. Of this hypogonadal subgroup, average abdominal girth was 112.2 cm, 35 percent had arterial hypertension, 21 percent were dyslipemic and 14 percent had benign prostatic hyperplasia or lower urinary tract symptoms. In this group, eight men had not yet been diagnosed with diabetes mellitus, 12 had not been diagnosed with dyslipemia and five had not yet been diagnosed with heart disease. These results indicate a link between erectile dysfunction and other major health conditions, and suggest that erectile dysfunction be considered a portal to men's health. Treatment for erectile dysfunction should involve corresponding treatment of underlying metabolic syndrome conditions and hypogonadism.

SERUM BIOMARKERS OF ENDOTHELIAL FUNCTION AND OXIDATIVE STRESS AFTER DAILY DOSING OF SILDENAFIL IN TYPE 2 DIABETIC MEN WITH ERECTILE DYSFUNCTION (Abstract 955)

It is known that erectile dysfunction (ED), particularly in diabetic men, is often characterized by increased oxidative stress and decreased endothelial function. Johns Hopkins researchers investigated whether daily long-term sildenafil treatment can provide vasculoprotective effects in these patients in a multi-center, randomized, double-blind, placebo-controlled two-arm study. Using a group of 300 men with documented ED and type 2 diabetes mellitus, researchers measured serum biomarkers for endothelial function (cyclic guanosine monophosphate, or cGMP) and oxidative stress (8 isoprostane). Inflammatory cytokines were measured using Bio-Plex suspension array sytem assays for interleukin-6 and interleukin-8. Erectile dysfunction was measured based on affirmative responses to question 4 of the Sexual Health Inventory-Male which asks about a patient's ability to maintain an erection for sexual intercourse.

Endothelial function increased and oxidative stress decreased in the treatment group with no significant change noted in the placebo group. Erectile function improved in the treatment group with 22.8 percent at baseline and 58.2 percent at four weeks. Statistically significant change was not observed in the placebo group with 27.8 percent at baseline vs 30.7 percent at four weeks.

BODY MASS INDEX AFFECTS THE RESPONSE TO SILDENAFIL IN MEN WITH MODERATE AND SEVERE LOWER URINARY TRACT SYMPTOMS (Abstract 1161)

A known link has been established between erectile dysfunction (ED) and cardiovascular risk factors such as obesity. A link has also been suggested between these factors and lower urinary tract symptoms (LUTS). This study from researchers in Chicago and New York analyzed a multi-center, double-blind, placebo-controlled study of men explores the connection between body mass index (BMI) and response to sildenafil in patients with ED and LUTS.

Men with scores less than or equal to 25 on the Erectile Function domain of the International Index of Erectile Funcation and an International Prostate Symptom Score greater or equal to 12 were given 50 mg of sildenafil (or matching placebo) nightly or one hour before sexual activity. After two weeks, dose was increased to 100 mg with the option of returning to the original dose. Patients were evaluated for erectile function, IPSS and flow rate (Qmax) and assessed by BMI category. Sildenafil improved erectile function scores independent of baseline BMI and IPSS scores were decreased in men taking sildenafil yet similar between BMI groups. Flow rate was not affected by the drug. Higher BMI appeared to have an association with more severe ED.

NEPHROLITHIASIS AND THE RISK OF CARDIOVASCULAR DISEASE (Abstract 1362)

Stone disease is a urologic condition whose etiology has not been completely characterized. Researchers in San Francisco and Boston have hypothesized a connection between stone disease and cardiovascular disease (CVD) in a large-cohort prospective analysis of 4,747 patients with a history of nephrolithiasis. CVD was defined as myocardial infarction, angina, need for coronary artery bypass graft and ischemic or hemorrhagic stroke.

Risk of CVD in men with a history of nephrolithiasis was 1.15; the risk was highest for angina among individual outcomes analyzed. No increased stroke risk was observed. While the statistical risk for CVD in stone disease patients was modest, results correlate with other studies investigating a link between CVD and nephrolithiasis and may contribute to the etiology of stone formation and the counseling of patients.

GENERAL OBESITY AS MEASURED BY WAIST CIRCUMFERENCE IS PREDICTIVE OF SEVERITY OF LOWER URINARY TRACT SYMPTOMS, SEXUAL DYSFUNCTION AND COMPONENTS OF THE METABOLIC SYNDROME (Abstract 1508)

Increased body mass index (BMI) and other components of metabolic syndrome have been linked to a number of urologic disorders, including erectile and voiding dysfunction. Researchers from New York and Illinois suggest that measurement of waist circumference may be a useful predictor for the severity of lower urinary tract symptoms (LUTS) and prostate volume. Baseline parameters - International Prostate Symptom Score (IPSS), prostate volume (measured by ultrasound), serum prostate-specific antigen (PSA), flow rate and erectile and ejaculatory dysfunction - were gathered, along with data on the incidence of hypertension, coronary artery disease and diabetes mellitus were compared among the 88 men in the study. Men were divided into three groups based on waist circumference (30-36 inches, 36-40 inches and greater than 40 inches).

Significant positive relationships between waist circumference and prostate volume, PSA, IPSS, erectile dysfunction and ejaculatory dysfunction were observed. Flow rates were inversely related. Higher waist circumference was also associated with an increase in diabetes mellitus, hypertension and coronary artery disease. These data suggest that increased waist circumference is associated with voiding and sexual dysfunction, and increase in metabolic syndrome disorders.

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About the American Urological Association: Founded in 1902 and headquartered near Baltimore, Maryland, the American Urological Association is the pre-eminent professional organization for urologists, with more than 15,000 members throughout the world. An educational nonprofit organization, the AUA pursues its mission of fostering the highest standards of urologic care by carrying out a wide variety of programs for members and their patients, including UrologyHealth.org, an award-winning on-line patient education resource, and the American Urological Association Foundation, Inc., formerly AFUD.

Contact: Wendy Isett
American Urological Association

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