Smoking causes erectile dysfunction through vascular disease

Effects of cigarette smoking on erectile dysfunction

Cigarette smoking is a leading cause of preventable morbidity and mortality in the United States. Although public policies have resulted in a decreased number of new smokers, smoking rates remain stubbornly high in certain demographics with 20% of all American middle-aged men smoking. In addition to the well-established harmful effects of smoking (i.e. coronary artery disease and lung cancer), the past three decades have led to a compendium of evidence being compiled into the development of a relationship between cigarette smoking and erectile dysfunction. The main physiologic mechanism that appears to be affected includes the nitric oxide signal transduction pathway. This review details the recent literature linking cigarette smoking to erectile dysfunction, epidemiological associations, dose dependency and the effects of smoking cessation on improving erectile quality.

Effects of smoking on plasma testosterone level and erectile function in rats

INTRODUCTION

There have been several conflicting reports of the effects of smoking on plasma testosterone levels and erectile function in clinical and animal studies.

AIM

This study was conducted to determine the actual effects of smoking on plasma testosterone levels and erectile function in rat-smoking models.

METHODS

For the exposure to cigarette smoke, the rats in a cage had a constant influx of smoke using a specially constructed device. Twenty-four Sprague Dawley (SD) rats for the acute cigarette exposure were allocated randomly into two groups: an experimental group and a control group. Thirty-six SD rats for the chronic cigarette smoke exposure were randomly divided into three groups: a control group and two experimental groups.

MAIN OUTCOME MEASURES

After exposure to smoking, the rats were subjected to electrical field stimulation of the cavernosal nerve to assess the erectile function, and blood was collected to measure the levels of plasma thiocyanate, testosterone, luteinizing hormone, and follicle-stimulating hormone. The histological changes of testes and corpora cavernosum (CC) were examined.

RESULTS

In the smoking groups, the thiocyanate levels were significantly higher than in the control group. Also, the mean arterial pressure (MAP) was significantly higher in the smoking groups, but the corpora cavernosal filling rate and maximal intracavernosal pressure/MAP were significantly lower than in the control group. The testosterone levels of experimental groups were significantly lower than those of control group, and the testosterone and thiocyanate levels were significantly correlated with erectile function components in chronic smoking groups. There was no significant histological change in the testes; however, in the CC, there was an increase in collagen fibers and decrease in smooth muscle and sinusoidal space in chronic smoking groups.

CONCLUSION

The results suggest that both the vasoconstrictor effects of smoking and the decrease in testosterone levels after chronic smoking had some effects on erectile function in rats.

Beneficial impact of exercise and obesity interventions on erectile function and its risk factors

INTRODUCTION

Erectile dysfunction (ED) is a multifaceted disease involving cardiovascular, metabolic, and hormonal factors and affects over 100 million men worldwide. ED has been shown to be a harbinger of underlying cardiovascular diseases (CVD), as there are common risk factors (aging, hypertension, obesity) and mechanistic basis.

AIM

To provide an update on clinical and experimental evidence regarding the impact of lifestyle modifications, such as exercise and diet, with respect to changes in erectile function.

MAIN OUTCOME MEASURES

Published evidence regarding the impact of aging, hypertension, and obesity on ED and CVD, as well as new experimental data linking obesity and diminished erectile responses.

METHODS

We reviewed the literature regarding common risk factors of ED and CVD, particularly involving obesity, as well as performed new analysis on the findings of other experimental studies involving diet and exercise interventions.

RESULTS

Physical inactivity negatively impacts on erectile function, and experimental and clinical exercise interventions have been shown to improve sexual responses and overall cardiovascular health. Mediterranean-style diets and a reduction in caloric intake have been found to improve erectile function in men with the aspects of the metabolic syndrome. In addition, both clinical and experimental studies have confirmed that combining the two interventions provides additional benefit to erectile function, likely via reduced metabolic disturbances (e.g., inflammatory markers, insulin resistance), decreased visceral adipose tissue, and improvement in vascular function (e.g., increased endothelial function).

CONCLUSIONS

Lifestyle modifications provide significant benefits to vascular health and erectile function in a population that is increasingly aged and more obese.

Cigarette smoking and erectile dysfunction: focus on NO bioavailability and ROS generation

INTRODUCTION

Thirty million men in the United States suffer from erectile dysfunction (ED) and this number is expected to double by 2025. Considered a major public health problem, which seriously affects the quality of life of patients and their partners, ED becomes increasingly prevalent with age and chronic smoking is a major risk factor in the development of ED.

AIM

To review available evidence concerning the effects of cigarette smoking on vascular changes associated with decreased nitric oxide (NO) bioavailability and increased reactive oxygen species (ROS) generation.

METHODS

We examined epidemiological and clinical data linking cigarette smoking and ED, and the effects of smoking on vascular NO bioavailability and ROS generation.

MAIN OUTCOME MEASURES

There are strong parallels between smoking and ED and considerable evidence supporting the concept that smoking-related ED is associated with reduced bioavailability of NO because of increased ROS.

RESULTS

Cigarette smoking-induced ED in human and animal models is associated with impaired arterial flow to the penis or acute vasospasm of the penile arteries. Long-term smoking produces detrimental effects on the vascular endothelium and peripheral nerves and also causes ultrastructural damage to the corporal tissue, all considered to play a role in chronic smoking-induced ED. Clinical and basic science studies provide strong indirect evidence that smoking may affect penile erection by the impairment of endothelium-dependent smooth muscle relaxation or more specifically by affecting NO production via increased ROS generation. Whether nicotine or other products of cigarette smoke mediate all effects related to vascular damage is still unknown.

CONCLUSIONS

Smoking prevention represents an important approach for reducing the risk of ED. The characterization of the components of cigarette smoke leading to ED and the mechanisms by which these components alter signaling pathways activated in erectile responses are necessary for a complete comprehension of cigarette smoking-associated ED.

Association between smoking, passive smoking, and erectile dysfunction: results from the Boston Area Community Health (BACH) Survey

INTRODUCTION

Although previous studies report an association between erectile dysfunction (ED) and smoking, few have examined the impact of passive smoke exposure on ED. This analysis examines the association of active and passive smoking and ED and investigates a dose-response effect of smoking.

METHODS

The Boston Area Community Heath (BACH) survey is a study of urologic symptoms in a racially and ethnically diverse population. BACH used a multistage stratified random sample to recruit 2301 men, aged 30-79 yr, from the city of Boston. ED was assessed using the five-item International Index of Erectile Function. Smoking and passive smoking were assessed by self-report. Analyses adjusted for sociodemographic and lifestyle factors and important chronic illnesses.

RESULTS

An association between smoking and ED was observed with a significant trend in increased risk of ED with cumulative pack-years of smoking (adjusted odds ratio [OR]=1.68; 95% confidence interval [CI], 1.03, 2.30 for > or =20 pack-years). Compared to never smokers not exposed to passive smoking, men who never smoked but were exposed to passive smoking had a moderate, statistically nonsignificant, increase in risk of ED (adjusted OR=1.33; 95%CI: 0.69, 2.55) comparable to the OR observed for a cumulative exposure of 10-19 pack-years of active smoking (adjusted OR=1.25; 95%CI, 0.68, 2.30).

CONCLUSIONS

Results indicate a dose-response association between smoking and ED with a statistically significant effect observed with > or =20 pack-years of exposure. Passive smoking is associated with a small, statistically nonsignificant increase in risk of ED comparable to approximately 10-19 pack-years of active smoking.