Elevated serum homocysteine level as an independent risk factor for erectile dysfunction: a prospective pilot case-control study

Association between folic acid, homocysteine, vitamin B12 and erectile dysfunction-A cross-sectional study

To evaluate the relationship between serum levels of folic acid (FA), homocysteine (HCY), vitamin B12 (B12) and erectile dysfunction (ED) and to explore their internal relationships. The study included 134 ED patients and 50 healthy controls. ED was assessed using IIEF-5 scores. ED group had lower median FA (6.08 versus 10.21; p < .001) and B12 (256.0 versus 337.5; p < .001) levels, and higher median HCY (11.4 versus 7.95; p < .001) levels, and these differences seemed to be more pronounced in the younger participants (age < 35 yr). FA decreased with the severity of ED (7.52 versus 6.15 versus 5.49 versus 3.97; p < .001), while HCY increased (10.35 versus 11.8 versus 12.9 versus 15; p < .001). Smoking and shift work were associated with lower FA levels. Multivariate analysis showed that serum FA and HCY revealed significant relation with ED. ROC analysis showed that FA ≤ 8.84 and HCY ≥ 10.35 were the best cut-off values for ED diagnosis. Both FA (r = -0.703, p < .001) and B12 (r = -0.576, p < .001) were negatively correlated with HCY. In conclusion, low FA levels and high HCY levels might be independent risk factors for ED. Low serum FA and B12 levels might co-cause high HCY levels and lead to ED.

Serum folic acid levels and erectile dysfunction: A meta-analysis and systematic review

The aim of this study was to assess the relationship between serum folic acid (FA) levels and erectile dysfunction (ED) through a meta-analysis. A research was conducted in MEDLINE via PubMed, Cochrane Library, EMBASE and Web of Science up to 22 November 2020 to identify studies related to FA and ED. Two authors independently screened the literature, evaluated methodological quality and extracted the data. We used RevMan5.3 and STATA 14.0 for meta-analysis. A total of six studies including 1,842 participants were included, and the results showed that the FA levels in the non-ED group were significantly higher than those in the ED group (MD = 3.37, 95% CI 1.49-5.52, p = 0.004). Subgroup analysis indicated that with the increase in ED severity, the difference in FA levels between groups was more obvious (MD: 1.99 vs. 4.63 vs. 5.63). The differences in FA levels between groups seem more significant in the younger group (MD = 4.87, 95% CI 2.58-6.89, p < 0.001) than in the older group (MD = 3.15, 95% CI 2.21-4.08, p < 0.001). In conclusion, FA deficiency is closely related to ED, and the degree of FA deficiency may reflect the severity of ED. In addition, the association seems to be more pronounced in the younger group.

Relationship between the risk factors of cardiovascular disease by testing biochemical markers and young men with erectile dysfunction: a case-control study

Background

Erectile dysfunction (ED) shares common risk factors with cardiovascular disease (CVD), such as diabetes mellitus (DM) and dyslipidemia, but the relationship between the risk factors of CVD in biochemical markers and young men with ED age 20–40 years is not fully clarified.

Methods

A total of 289 ED outpatients (20–40 years old) were allocated under ED group, based on patients’ complaints and physical examinations. According to the frequency matching ratio of 1:4, 1,155 male individuals (20–40 years old) without ED were set as control group. All participants were tested for lipid profiles including total cholesterol (TC), triglyceride (TG), high density lipoprotein (HDL), low density lipoprotein (LDL), blood glucose (BG), homocysteine (HCY), liver function including alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and renal function including uric acid (UA) and creatinine (CR). The study was designed to compare the two groups using an established binary logistic regression analysis model. The ED group was then subdivided into a younger ED group (20–30 years old) and an older ED group (31–40 years old) for further comparisons.

Results

After comparison, no obvious differences were found in medians of age, TC, TG, HDL, HCY, UA, and ALT in the two groups. Median LDL, BG, and CR were significantly higher and AST was much lower in the ED group (P<0.01). In binary logistic regression analysis, odds ratios (OR) for LDL, BG, CR, and AST were 1.279, 1.237, 1.026, and 0.978, respectively. The sensitivity value and specificity value were 43.25% and 72.56%, respectively. The medians of LDL, TG, and TC were higher and HDL was much lower in the older ED group, as compared with the younger group (P<0.05). No significant differences were displayed in medians of other biochemical markers in the above comparisons.

Conclusions

Elevated LDL, BG, and CR were related factors of ED in young men. Lipid profile was significantly different between young men with ED aged 20–30 and 31–40 years.

Novel predictive risk factor for Erectile Dysfunction: Serum folic acid

The purpose of this study was to compare the serum Folic Acid (FA) levels in patients with Erectile Dysfunction (ED) and healthy controls and whether levels vary with its severity. The study was carried out on 77 sexually active individuals, out of which 41 complained of ED and 36 were apparently normal. Patients were excluded if they had any diseases known to cause ED. The severity was further categorised based on IIEF-5 scores. Blood serum levels of testosterone, lipid profile, random blood sugar, liver function test, renal function test and FA levels were obtained in each patient. Independent-samples t test of significance was used when comparing between two means. Pearson's correlation coefficient (r) test was used for correlating data. All clinical and biochemical parameters except FA were comparable in both the groups. FA levels were significantly decreased in ED group (5.29 vs. 10.8; p value = .004). Smoking habits were comparable between the groups, and FA levels did not vary among smokers and nonsmokers (p value = .46). Serum FA levels significantly declined with increasing severity of ED (8.28 vs. 5.56 vs. 4.37 vs. 3.5; p value < .001). Thus, decreased FA might possibly be one of the novel risk factors for ED.

Melatonin Treatment Ameliorates Hyperhomocysteinemia-Induced Impairment of Erectile Function in a Rat Model

BACKGROUND

Hyperhomocysteinemia (HHcy) has been reported to be strongly correlated with the occurrence of erectile dysfunction (ED), but the mechanisms are not fully understood. Moreover, whether melatonin could be a potential treatment of HHcy-induced ED needs to be elucidated.

AIM

The aim of this study was to investigate the effects of melatonin on HHcy-induced ED and the potential mechanisms via modulating oxidative stress and apoptosis.

METHODS

The Sprague-Dawley (SD) rat model of HHcy was induced by 7% methionine (Met)-rich diets. 36 male SD rats were randomly distributed into 3 groups (n = 12 per group): control group, 7% Met group, and 7% Met + melatonin (Mel; 10 mg/kg, intraperitoneal injection) treatment group. After 4 weeks, the erectile function of all rats was evaluated by electrical stimulation of the cavernous nerve. Histologic and molecular alterations of the corpus cavernosum were also analyzed by immunofluorescence, immunohistochemistry, enzyme-linked immunosorbent assay, Western blotting, and polymerase chain reaction.

OUTCOMES

HHcy-induced ED rat models were successfully established, and Mel could preserve erectile function mainly through inhibiting oxidative stress via the Erk1/2/Nrf2/HO-1 signaling pathway and suppression of apoptosis.

RESULTS

Erectile function was significantly reduced in the rats with HHcy compared with that in the control group and was ameliorated in the HHcy rats treated with Mel. Compared with the control group, the rats in the HHcy group showed the following: (1) higher levels of total plasma homocysteine; (2) fewer neuronal nitric oxide synthase-positive cells in the corpus cavernous; (3) higher levels of reactive oxygen species and malondialdehyde, higher expression levels of nicotinamide adenine dinucleotide phosphate oxidase, and lower activities of superoxide dismutase, indicating an overactivated oxidative stress; (4) lower expression levels of Erk1/2/Nrf2/HO-1 signaling pathway components; and (5) higher levels of apoptosis, as determined by the expression levels of Bax, Bcl-2, and caspase 3. Mel treatment improved the erectile response, as well as histologic and molecular alterations.

CLINICAL TRANSLATION

Our study on a rodent model of HHcy provided evidence that Mel could be a potential therapeutic method for HHcy-related ED.

CONCLUSIONS

Mel treatment improves erectile function in rats with HHcy probably by potential antioxidative stress activity. This finding provides evidence for a potential new therapy for HHcy-induced ED. Tang Z, Song J, Yu, Z, et al. Melatonin Treatment Ameliorates Hyperhomocysteinemia-Induced Impairment of Erectile Function in a Rat Model. J Sex Med 2019;16:1506-1517.

Folic acid supplementation improves erectile function in patients with idiopathic vasculogenic erectile dysfunction by lowering peripheral and penile homocysteine plasma levels: a case-control study

BACKGROUND

Erectile dysfunction (ED) has common risk factors with many cardiovascular (CV) impairments. In view of these facts, hyperhomocysteinemia (HHcys) has been postulated for involvement in endothelial dysfunction.

OBJECTIVES

We evaluated peripheral and penile homocysteine (Hcys) plasma levels before and after folic acid supplementation in idiopathic vasculogenic erectile dysfunction (ED) patients.

MATERIALS AND METHODS

This study included 50 consecutive patients and 50 consecutive healthy controls that were recruited from December 2017 to December 2018. The patients received folic acid (FA) daily for 3 months and were evaluated by the abridged 5-item International Index of Erectile Function (IIEF-5) and penile duplex before and after therapy, in addition to plasma Hcys levels.

RESULTS

Our study showed improvement in the severity of ED in our patients as all of them became mild to moderate ED after folic acid administration. Additionally, the median scores of IIEF-5 significantly increased from 6 to 14, respectively (p < 0.001). Furthermore, the median peripheral and penile Hcys plasma levels (μmol/l) significantly decreased after folic acid administration as 39 patients with moderate ED and 11 patients with severe ED were 0.62, 0.34, 5.37, 0.37, respectively, became mild to moderate ED with their median peripheral and penile Hcys plasma levels became 0.19, 0.15, p < 0.001, <0.001, respectively. Peripheral Hcys level correlates significantly with penile Hcys before and after folic acid administration (r: -0.06 p: 0.8, r: 0.9, p < 0.001, respectively).

DISCUSSION AND CONCLUSION

Recently, an emerging body of evidence suggests a role for Hcys and folate in erectile function. Interestingly, our interventional study is one of the first that evaluated the effect of folic acid supplementation on HHcys where it demonstrated a significant decrease in peripheral and penile Hcys plasma levels after folic acid administration. Thus, FA should be prescribed concomitantly with phosphodiesterase type 5 inhibitors in ED patients.

Association between homocysteine, vitamin B 12 , folic acid and erectile dysfunction: a cross-sectional study in China

OBJECTIVES

Erectile dysfunction (ED) affects up to 53.4% of men aged 30-80 years. In this study, we aimed to examine the association between homocysteine (HCY), vitamin B₁₂ (B12), folic acid (FA) and ED.

DESIGN

Cross-sectional study.

SETTING

Guangxi, China.

PARTICIPANTS

A total of 1381 participants who completed questionnaires were included, between September 2009 and December 2009.

MEASURES

ED was evaluated by the International Index of Erectile Function scores. Also, the values of HCY, B12 and FA were acquired. Then, regression and between-group analyses were performed.

RESULTS

No association between FA and ED was found. Significant correlations between HCY and ED were found-the relationships between these two parameters were most notable in men aged over 60 years and in men living alone (bachelors or bachelorhood). B12 levels were higher in men with ED (718.53±234.37 pg/mL vs 688.74±229.68, p=0.015). Using multinomial logistic regression analyses, B12 levels were related to mild ED (multivariate adjusted analysis: OR 1.620, 95% CI 1.141 to 2.300, p=0.007), especially among men aged 40-49 years (OR 2.907, 95% CI 1.402 to 6.026, p=0.004).

CONCLUSIONS

We report, for the first time, a relationship between B12 levels and ED. We also found specific cohorts of men for whom the relationship between HCY levels and ED is most prominent. Further studies are required to elucidate the mechanisms underlying these relationships-these may ultimately result in new therapies for ED.

Low serum folic acid can be a potential independent risk factor for erectile dysfunction: a prospective case-control study

PURPOSE

The purpose of the study was to compare serum level of folic acid (FA) in patients with erectile dysfunction (ED) versus healthy controls and to assess its correlation with other well-known confounders for ED.

METHODS

Our prospective study compared FA in 60 patients with ED versus 30 healthy controls. Patients were excluded if they had any hormonal disorders, Peyronie's disease, or decompensated systemic illnesses. ED was evaluated by the validated Arabic version of the abbreviated five-item form of the International Index Of Erectile Function and confirmed by penile duplex. Serum FA level was assayed using ELIZA. Mann-Whitney, Kruskal-Wallis, and Chi-square tests and Spearman correlation were used as appropriate and confirmed by logistic regression model.

RESULTS

Our study revealed that the median FA of the cases and the controls were 7.1 ng/mL and 13.4 ng/mL, respectively, and this difference was of high statistical significance (p < 0.001). Moreover, our study demonstrated significant relations between serum FA with DM, HTN, smoking, age, and cholesterol (p 0.01, 0.03, 0.014, 0.001, and 0.015, respectively). Our study showed that the best cut-off point of serum FA to detect patients with ED was found to be ≤ 9.42 with sensitivity of 80.00%, specificity of 93.33% and area under curve (AUC) of 91.3%.

CONCLUSION

Serum FA level decreased as the severity of ED increased even after adjustment of age, serum testosterone, DM, HTN, and smoking. FA deficiency might be an independent risk factor of ED.

Folate: a possible role in erectile dysfunction?

A growing body of evidence suggests a role for homocysteine (Hcys) and folate (FA) in erectile function (EF): Hcys appears to impair EF affecting endothelium via several mechanism whereas the role of FA remains to be elucidated, besides decreasing Hcys. To assess correlation between erectile dysfunction (ED) and serum levels of FA, Hcys, and B12, we enrolled 31 patients affected by ED (Group A; age 52.83 ± 11.89 years) and 31 healthy adults (Group B; age 49.14 ± 13.63 years). Fasting blood samples were taken for each subject. ED was assessed by the International Index of Erectile Function-5 (IIEF-5). IIEF-5 mean score was significantly lower in Group A than in Group B (10.71 ± 4.24 versus 23.32 ± 1.33, p < .001). Compared to Group B, Group A also showed significantly lower serum FA levels (5.11 ± 1.79 versus 7.9 ± 3.55 ng/ml, p < .001) and significantly higher serum Hcys levels (13.61 ± 3.55 versus 9.17 ± 2.32 µmol/L, p < .001). No significant correlation was observed between Hcys and FA both groups. Our results showed a significant association among ED, FA deficiency and hyperomocisteinemia. Lack of correlation between FA and Hcys suggests that FA deficit may directly impair EF.

Serum Homocysteine Levels in Men with and without Erectile Dysfunction: A Systematic Review and Meta-Analysis

OBJECTIVES

Elevated levels of serum homocysteine (Hcy) have been associated with cardiovascular diseases and endothelial dysfunction, conditions closely associated with erectile dysfunction (ED). This meta-analysis was aimed to assess serum Hcy levels in subjects with ED compared to controls in order to clarify the role of Hcy in the pathogenesis of ED.

METHODS

Medline, Embase, and the Cochrane Library were searched for publications investigating the possible association between ED and Hcy. Results were restricted by language, but no time restriction was applied. Standardized mean difference (SMD) was obtained by random effect models.

RESULTS

A total of 9 studies were included in the analysis with a total of 1320 subjects (489 subjects with ED; 831 subjects without ED). Pooled estimate was in favor of increased Hcy in subjects with ED with a SMD of 1.00, 95% CI 0.65-1.35, p < 0.0001. Subgroup analysis based on prevalence of diabetes showed significantly higher SMD in subjects without diabetes (1.34 (95% CI 1.08-1.60)) compared to subjects with diabetes (0.68 (95% CI 0.39-0.97), p < 0.0025 versus subgroup w/o diabetes).

CONCLUSIONS

Results from our meta-analysis suggest that increased levels of serum Hcy are more often observed in subjects with ED; however, increase in Hcy is less evident in diabetic compared to nondiabetic subjects. This study is registered with Prospero registration number CRD42018087558.