Serum Vitamin D Level and Erectile Dysfunction in Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis

Association of serum vitamin D and the risk of cardiovascular diseases among diabetic patients: A systematic review and meta-analysis

BACKGROUND

The emerging role of vitamin D has drawn the attention of researchers around the world, including its involvement in cardiovascular complications among individuals with diabetes.

AIM

This study aimed to obtain comprehensive evidence on the association between serum vitamin D level and the risk of cardiovascular disease among patients with diabetes.

METHODS

Systematic search was performed on July 1st, 2023, to identify and screen published literature reporting the association between vitamin D and cardiovascular disease among diabetic patients in six databases. Each eligible study was appraised for its quality using modified Newcastle Ottawa Scale for cross-sectional and cohort studies. Meta-analysis was performed using Dersimonian-Laird random effect model or fix-effect model. The heterogeneity and publication bias were judged based on percentage of I2 and the symmetry of Begg's funnel plot, respectively.

RESULTS

As many as 22 studies were found eligible for the systematic review. A meta-analysis from 13 studies comprising of 3850 and 1797 (control and exposure groups, respectively) revealed that serum vitamin D level was significantly lower in patients with diabetes and cardiovascular diseases (Z = 4.89; p-total<0.001; SMD = 0.68 [95%CI: 0.41-0.95]), yet the heterogeneity was high. Following the adjustment of removing the potential outliers, the same results were still observed (Z = 6.19; p-total<0.001; SMD = 0.35 [95%CI: 0.24-0.46]). Though decreased, high heterogeneity could not be resolved, resulting in moderate level of this evidence. Another pooled analysis of 7 studies with 4211 patients in control group and 2381 patients in exposure group revealed that lower level of serum vitamin D is a risk factor for cardiovascular disease incidence among diabetic patients (Z = 4.89; p-total<0.001; OR: 1.76 [95%CI: 1.4-2.2]).

CONCLUSION

Serum vitamin D level status is a risk factor for developing cardiovascular diseases among diabetic patients, hence should be carefully monitored and maintained.

PROSPERO REGISTRATION

CRD42023437698.

Association between sexual dysfunction and vitamin D in Swedish primary health care patients born in the Middle East and Sweden

The present study investigated primary care patients and compared self-reported sexual health in Swedes and Middle Easterners; analysed differences within and between the groups and analysed differences in 25-hydroxyvitamin D [25(OH)D] levels between the groups. 522 patients responded to a health questionnaire that included items on sexual health: 225 Middle Easterners from Iran, Iraq, and Turkey and 297 Swedes. Logistic regression was used to calculate the odds ratio (OR). Middle Easterners reported less sexual dysfunction than Swedes, and 75.8% of them and 18.9% of Swedes presented a 25(OH)D of < 50 nmol/L. The crude OR for reporting sexual dysfunction was 70% higher in Swedes compared to Middle Easterners (OR 1.70, 95% CI 1.15-2.50). This OR remained significant after adjustment for age, gender, waist circumference, and reported sexual desire. However, the significance disappeared after additional adjustment for 25(OH)D. In both groups, more females than males reported insufficient sexual desire. More female Middle Easterners reported sex life dissatisfaction. More female Swedes reported sexual dysfunction. Vitamin D could explain an association between gender and sex life dissatisfaction in Middle Easterners, and age could explain an association between gender and sexual dysfunction in Swedes. Age, waist circumference, and 25(OH)D levels were significant covariates in the logistic regression models. Results from the present study suggest that 25(OH)D variation partly explains differences in sexual dysfunction between the groups and between genders within the groups. Vitamin D therapy should be investigated to determine if these results are clinically useful.

The Italian Society of Andrology and Sexual Medicine (SIAMS), along with ten other Italian Scientific Societies, guidelines on the diagnosis and management of erectile dysfunction

PURPOSE

Erectile dysfunction (ED) is one of the most prevalent male sexual dysfunctions. ED has been in the past mistakenly considered a purely psycho-sexological symptom by patients and doctors. However, an ever-growing body of evidence supporting the role of several organic factors in the pathophysiological mechanisms underlying ED has been recognized.

METHODS

The Italian Society of Andrology and Sexual Medicine (SIAMS) commissioned an expert task force involving several other National Societies to provide an updated guideline on the diagnosis and management of ED. Derived recommendations were based on the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system.

RESULTS

Several evidence-based statements were released providing the necessary up-to-date guidance in the context of ED with organic and psychosexual comorbidities. Many of them were related to incorrect lifestyle habits suggesting how to associate pharmacotherapies and counseling, in a couple-centered approach. Having the oral therapy with phosphodiesterase type 5 inhibitors as the gold standard along with several other medical and surgical therapies, new therapeutic or controversial options were also discussed.

CONCLUSIONS

These are the first guidelines based on a multidisciplinary approach that involves the most important Societies related to the field of sexual medicine. This fruitful discussion allowed for a general agreement on several recommendations and suggestions to be reached, which can support all stakeholders in improving couple sexual satisfaction and overall general health.

Mechanisms Suggesting a Relationship between Vitamin D and Erectile Dysfunction: An Overview

Vitamin D deficiency (VDD) and erectile dysfunction (ED) heavily burden the male population. The higher prevalence of both conditions in the elderly suggests a possible relationship between the two conditions. In addition, in vitro, animal, and human studies have revealed several mechanisms that may relate VDD to ED. The main mechanism by which vitamin D might exert its action on sexual function appears to be through the regulation of endothelial function. Indeed, VDD correlates with several markers of endothelial function. The action of vitamin D on the endothelium would be exercised both indirectly through its intervention in inflammatory processes and through the production of oxygen free radicals, and directly through the regulation of vascular stiffness, the production of nitric oxide, and the regulation of vessel permeability. Furthermore, the ubiquitous distribution of the vitamin D receptor in the human body means that this hormone can also exert a beneficial effect on erectile function by interfering with those comorbidities significantly associated with ED, such as hypertension, diabetes mellitus, hypercholesterolemia, chronic kidney disease, and hypogonadism. In this review, we thoroughly and carefully presented the evidence and mechanisms that would appear to relate vitamin D levels to erectile function. Furthermore, we have summarized the meta-analytic evidence for and against this association to provide a true representation of this topic. Data published to date suggest that low levels of vitamin D could contribute to worsening erectile function through several mechanisms. Therefore, vitamin D levels should be measured in patients with ED and maintained at adequate levels by specific supplementation in case of deficiency. However, the low quality and heterogeneity of clinical trials evaluating the effects of vitamin D administration on erectile function and ED-associated comorbidities do not allow for a univocal conclusion, and indicate the need for further studies to analyze these aspects.