Exploration of the association between serum uric acid and testosterone in adult males: NHANES 2011-2016

Uric acid mediates the association between testosterone and α-Klotho among males: results from the NHANES 2013-2016

PURPOSE

This study initially conducted a cross-sectional analysis to examine the association between total testosterone (TT), uric acid, and Klotho. The investigation examined whether uric acid mediates the association between TT and Klotho in males.

METHODS

Based on data from the National Health and Nutrition Examination Survey (NHANES) 2013-2016, this study performed weighted multivariable-adjusted linear regression to evaluate the association between TT, uric acid, and α-Klotho. Then, mediation analysis was conducted to delineate the potential mediating role of uric acid in the TT-Klotho association.

RESULTS

Multivariable linear regression analyses revealed inverse relationships between TT and uric acid (β = - 2.75, 95% CI: - 4.21, 1.28, p < 0.001) and between uric acid and α-Klotho (β = - 4.80, 95% CI: - 6.47, - 3.13, p < 0.001). Conversely, a positive correlation existed between TT and α-Klotho (β = 5.38, 95% CI: 2.23, 8.53, p < 0.001). Updated subgroup analyses show that the association strength between α-Klotho, TT, and uric acid levels was consistent across various population settings without significant variations. Restricted cubic spline analysis identified a non-linear association between TT and uric acid with an inflection point at 201 ng/mL. Mediation analysis confirmed uric acid-mediated 18.59% of the association between TT and α-Klotho (p < 0.001), highlighting its significant intermediary role.

CONCLUSION

This study elucidates the complex interrelationship between TT, uric acid, and α-Klotho, highlighting uric acid's significant mediating role. These findings provide novel insights into the hormonal and metabolic mechanisms underlying age-related processes and longevity.

Uncovering the Potential Mechanisms and Effects of Hyperuricemia and its Associated Diseases on Male Reproduction

Male fertility and metabolic disorders, including obesity and diabetes, are closely connected. Since hyperuricemia and metabolic syndrome are strongly related, male fertility and hyperuricemia may, to some degree, be associated. According to recent studies, hyperuricemia imposes various effects on sex hormones, semen quality, and male erectile dysfunction. Some researchers claim that uric acid worsens male semen and raises the risk of erectile dysfunction (ED), while others state that it safeguards both penile erection and male semen. Additionally, it has been shown that gout and metabolic syndrome also raise the risk of ED. To clarify this controversy, the influence and potential mechanisms of hyperuricemia on ED, semen quality, sex hormone levels, and the effects of hyperuricemia-related disorders on ED will be comprehensively summarized.

Association of serum uric acid with male sexual hormones and erectile dysfunction: a bidirectional 2-sample Mendelian randomization analysis

Background

Observational studies indicated that serum uric acid (SUA) was associated with male sexual hormones and erectile dysfunction (ED). However, their relationship was still heterogeneous.

Aim

This study conducted 2-sample univariate mendelian randomization (UVMR) and multivariate mendelian randomization (MVMR) to explore the causal relationship between SUA and sexual hormones as well as ED.

Methods

Genetic variants associated with SUA were derived from the UK Biobank database (N = 437 354). Outcomes from the IEU Open GWAS and summary data sets were sexual hormones (sex hormone-binding globulin [SHBG], testosterone, estradiol [E2], follicle-stimulating hormone, luteinizing hormone) and ED, with 3301 to 625 650 participants. UVMR analysis primarily utilized the inverse variance weighted method, complemented by MVMR analysis. Thorough sensitivity analyses were carried out to ensure the reliability of results. Moreover, mediation analysis was conducted to estimate the mediated effect between SUA and outcomes.

Outcomes

The primary outcomes included results of UVMR and MVMR analysis and mediation analysis, along with sensitivity analyses involving the Cochran Q test, the MR Egger intercept test, leave-1-out analysis, and the MR-PRESSO method (mendelian randomization pleiotropy residual sum and outlier).

Results

UVMR analysis revealed that an elevated SUA level could decrease levels of SHBG (β = -0.10, P = 1.70 × 10-7) and testosterone (β = -0.10, P = 5.94 × 10-3) and had a positive causal effect on ED (odds ratio, 1.10; P = .018). According to reverse mendelian randomization results, increased levels of SHBG (β = -0.06, P = 4.82 × 10-4) and E2 (β = -0.04, P = .037) could also reduce SUA levels. As shown by MVMR analysis, SUA had a negative effect on SHBG and testosterone levels (P < .05), while the significant causal relationship between SUA and ED disappeared. Furthermore, SHBG mediated 98.1% of the effect of SUA on testosterone levels. Results of other mendelian randomization analyses were not statistically significant. No pleiotropy was found by sensitivity analysis in this study.

Clinical Implications

Given the causal relationship between SUA and sexual hormones, we must focus on SUA and E2 levels in men, especially patients with hypogonadism and ED.

Strengths and Limitations

This study evaluated the causal effect of SUA on male sexual hormones and ED genetically for the first time, clarifying the common biases in observational studies and confirming the negative relationship between SUA and testosterone level. Limitations include a population based on European ancestry, some crossover of the samples, and unobserved confounding factors.

Conclusion

Genetic studies provide evidence for the causal relationship between SUA and male sexual hormones (SHBG, testosterone, E2), while the relationship between SUA and ED should be further evaluated.

Decoding connections in the European population: serum uric acid, sex hormone-binding globulin, total testosterone, estradiol, and female infertility - advanced bidirectional and mediative Mendelian randomization

Background

Despite observational links between serum uric acid (SUA), sex hormone-related phenotypes, and female infertility, the causality behind these associations remains uncertain.

Objective

This study utilizes Bidirectional Two-Sample and Mediation Mendelian Randomization to explore the causal relationships and mediation effects of sex hormone-binding globulin (SHBG), total testosterone (TT), and estradiol on these associations.

Methods

We analyzed single-nucleotide polymorphisms (SNPs) associated with SUA and sex hormone levels using data from large-scale GWAS of European populations. Female infertility data were sourced from 6,481 cases and 75,450 controls in the FinnGen Consortium. We employed methods including Inverse Variance Weighted (IVW), Weighted Median, and MR-Egger regression to assess causality.

Results

We found that elevated SUA levels causally increase the risk of female infertility (IVW OR: 1.13, P=0.047). Elevated SUA levels significantly decrease SHBG levels (β=-0.261; P=2.177e-04), with SHBG mediating 27.93% of the effect of SUA on infertility (OR=0.854; 95%CI, 0.793-0.920; P=2.853e-05). Additionally, elevated TT levels, which were associated with decreased SUA levels (β=-0.127), showed an indirect effect on infertility mediated by SUA (β=-0.0187; 95% CI, -0.041 to -0.003; P=0.046).

Conclusion

Our findings demonstrate causal links between high SUA and increased risk of female infertility mediated by hormonal factors such as SHBG and TT. These insights suggest new avenues for infertility treatment and highlight the need for further research into these mechanisms.

Nonlinear dose-response association of moderate-to-vigorous physical activity with hyperuricemia in US adults: NHANES 2007-2018

BACKGROUND

The relationship between physical activity and hyperuricemia (HUA) remains inconsistent, and the dose-response association between moderate-to- vigorous physical activity (MVPA) level and HUA still unclear. In this study, we aimed to investigate the dose-response association of MVPA with HUA, and to explore an appropriate range of MVPA level for preventing HUA.

METHODS

Data from the US National Health and Nutrition Examination Survey (NHANES) 2007-2018 were used, including 28740 non-gout adult Americans. MVPA level was self-reported using the Global Physical Activity Questionnaire and serum uric acid was measured using timed endpoint method. The dose-response relationship between MVPA level and HUA was modeled with restricted cubic spline analysis. Logistic regression analysis were applied to estimate odd ratios (ORs) and 95% confidence intervals (CIs) of the relationships between MVPA level and HUA.

RESULTS

A total of 28740 adults were included in the study (weighted mean age, 47.3 years; 46.5% men), with a prevalence rate of HUA was 17.6%. The restricted cubic spline functions depicted a general U-shaped relationship between MVPA level and HUA. The MVPA level of 933 and 3423 metabolic equivalent (MET) -min/wk were the cut-off discriminating for the risk of HUA. Participants with MVPA levels in the range of 933-3423 MET-min/wk had lower risk of HUA and they had the lowest risk when MVPA levels at around 1556 MET-min/wk. Compared with the moderate-activity group (600-2999 Met-min/wk), the low-activity group (< 600 Met-min/wk) had a greater risk of HUA (OR, 1.13 [95%CI, 1.02-1.26]) after fully adjusting for potential confounders.

CONCLUSIONS

Compared with the moderate MVPA level, the low MVPA level was associated with the higher risk of HUA. And there may be a U-shaped dose-response relationship between MVPA level and HUA. When MVPA level was approximately 933-3423 MET-min/wk, the risk of HUA may at a lower level and the risk reached the lowest when MVPA level at around 1556 MET-min/wk.

Traditional Chinese Medicine formula Wubi Shanyao Pills protects against reproductive aging by activating SIRT1/3 to reduce apoptosis

ETHNOPHARMACOLOGICAL RELEVANCE

The study of male reproductive aging and its associated concerns holds significant importance within the realm of health issues affecting the elderly population. Wubi Shanyao Pills (WSP), a traditional Chinese patent medicine originating from the Tang Dynasty, has been recognized for its ability to enhance male sexual functions while also tonifying the kidney and spleen. Nevertheless, the precise effects and underlying mechanisms through which WSP ameliorates the decline in reproductive function among aging men remain uncertain.

AIM OF THE STUDY

This study elucidated the distinctive impacts of WSP on ameliorating the decline in reproductive function caused by natural aging, as well as its underlying mechanisms.

MATERIALS AND METHODS

Initially, male mice at the age of 15 months were administered WSP orally at doses of 0.375, 0.75, and 1.50 g/kg per day for a duration of 8 consecutive weeks. The impact of WSP on age-related manifestations in naturally aging mice was assessed based on their behavioral performance. The renal function of the mice was evaluated by measuring serum biochemical indicators, including Creatinine (CR), Uric acid (UA), and Blood urea nitrogen (BUN). Additionally, Superoxide dismutase (SOD) and Malonaldehyde (MDA) levels in renal tissue were determined using applied chemistry methods. Then assessed the levels of Nitric oxide (NO), Total nitric oxide synthase (T-NOS), Guanosine cyclase (GC), and Cyclic guanosine monophosphate (cGMP) in the penile tissue, as well as the expression of Endothelial nitric oxide synthase (eNOS) and Guanylate Cyclase Activator (GUCA) protein, in order to investigate the erectile function of the penis. Additionally, the quality of epididymal sperm was examined using an electron microscope. Furthermore, the serum sex hormone level and related protein expression were determined through the utilization of enzyme-linked immunosorbent assay and immunohistochemistry techniques. Pathological alterations and the ultrastructure of the testis were investigated using hematoxylin-eosin staining and transmission electron microscopy. Subsequently, the apoptosis of spermatogenic cells in the testes was assessed employing TUNEL, immunofluorescence, western blotting, and quantitative real-time polymerase chain reaction.

RESULTS

The administration of WSP has been found to enhance the behavioral performance and sexual behavior in aged mice. It's also could increase in serum levels of CR, UA, and BUN, as well as the elevation of SOD activity in kidney tissue, which subsequently leads to a reduction in MDA levels and an improvement in the structural damage caused by aging in the kidney tissue. Consequently, the renal function is enhanced. Additionally, WSP has been observed to elevate the levels of NO, T-NOS, GC, and cGMP in penile tissue, along with an increase in eNOS and GUCA protein expression, indicating an improvement in penile erectile function. The administration of WSP resulted in a decrease in the occurrence of programmed cell death in testicular germ cells, leading to an enhancement in sperm quality and the overall function of testicular spermatogenesis. This improvement can be attributed to the modulation of hormone levels and the regulation of SIRT1/3, p53, FOXO3, Bax, and Caspase-3 expression.

CONCLUSION

Collectively, our findings indicate that the administration of WSP has the potential to impede the occurrence of programmed cell death in testicular cells by modulating the expression of SIRT1/3 and subsequent genes associated with apoptosis. Consequently, this regulatory mechanism facilitates the proliferation of testicular cells and sustains the spermatogenic function of the testes. Consequently, by modulating the levels of sexual hormones in naturally aging mice, WSP ultimately enhances the quality of sperm and reproductive function. Concurrently, it also ameliorates age-related behavioral changes, renal function, and erectile function.

Association of serum uric acid levels with benign prostatic hyperplasia in US men: results from NHANES 2005-2008

BACKGROUND

The relationship between uric acid (UA) and benign prostatic hyperplasia (BPH) is controversial and has rarely been studied in American populations.

METHODS

Data from two cycles of the National Health and Nutrition Examination Surveys, comprising data from 2005 to 2008, were used. The majority of BPH were identified by self-report. We investigated the relationship between UA and BPH using univariate and multivariate logistic regression analyses.

RESULTS

2,845 participants were enrolled in the study, including 531 participants with BPH and 2,314 controls. After fully adjusting for all confounders, the risk of developing BPH was reduced by 18% for every 100 μmol/L increase in UA (OR = 0.82, 95% CI: 0.69-0.97, p = 0.023). Participants in the highest quartile of UA were found to have a reduced likelihood of developing BPH (ORQ4vs1 = 0.61, 95% CI: 0.41-0.91) in comparison to those in the lowest quartile of UA. Subgroup analyses found that among those younger than 60 years, non-Hispanic whites, former smokers, heavy drinkers, those without diabetes, or those with hypertension, high UA remained negatively associated with BPH.

CONCLUSIONS

The above results suggest that UA may be a potential protective factor for BPH, but the mechanism needs to be further explored.

Uric acid en route to gout

Gout and hyperuricemia (HU) have generated immense attention due to increased prevalence. Gout is a multifactorial metabolic and inflammatory disease that occurs when increased uric acid (UA) induce HU resulting in monosodium urate (MSU) crystal deposition in joints. However, gout pathogenesis does not always involve these events and HU does not always cause a gout flare. Treatment with UA-lowering therapeutics may not prevent or reduce the incidence of gout flare or gout-associated comorbidities. UA exhibits both pro- and anti-inflammation functions in gout pathogenesis. HU and gout share mechanistic and metabolic connections at a systematic level, as shown by studies on associated comorbidities. Recent studies on the interplay between UA, HU, MSU and gout as well as the development of HU and gout in association with metabolic syndromes, non-alcoholic fatty liver disease (NAFLD), and cardiovascular, renal and cerebrovascular diseases are discussed. This review examines current and potential therapeutic regimens and illuminates the journey from disrupted UA to gout.

Association between serum uric acid and measures of adiposity in Chinese adults: a cross-sectional study

OBJECTIVE

The purposes of the study were to investigate the detailed association of serum uric acid (SUA) with visceral fat area (VFA) and body fat percentage (BFP) as calculated by bioelectrical impedance analysis (BIA) and build non-invasive diagnosis models of hyperuricaemia by combining obesity-related indicators, age and sex.

METHOD

A total of 19 343 adults were included. Multivariable regression analysis models were employed to analyse the association of SUA with VFA and BFP. Receiver operating characteristic curves were generated to diagnose hyperuricaemia in adults.

RESULTS

After fully adjusting for covariates, SUA was positively associated with VFA, BFP and body mass index (BMI) with βs of 0.447, 2.522 and 4.630 (95% CI= (0.412 to 0.482), (2.321 to 2.723) and (4.266 to 4.994)). After stratification by gender, this association persists (p<0.001). Fitted smoothing curves identified non-linear relationships between SUA and both VFA and BMI after full adjustment in males (inflection points: 93.9 cm² and 30.9 kg/m²). A non-linear relationship also exists between SUA and BFP in females (inflection point: 34.5%). A combined model incorporating BFP, BMI, age and sex exhibited the best ability to diagnose hyperuricaemia (AUC (area under the curve) =0.805, specificity=0.602, sensitivity=0.878). For normal-weight and lean populations, individuals with hyperuricaemia tended to have higher levels of VFA and BFP in females and males, respectively (p<0.001). The combination of VFA, BFP, BMI, age and sex exhibited the best ability to diagnose hyperuricaemia in normal-weight and lean populations (AUC=0.803, specificity=0.671, sensitivity=0.836).

CONCLUSION

VFA and BFP are independent factors associated with SUA. In males, SUA shows a non-linear relationship with VFA and BMI. In females, SUA and BFP exhibit a non-linear relationship. In normal-weight and lean individuals, the accumulation of VFA and BFP may be involved in hyperuricaemia. VFA and BFP were helpful in diagnosing hyperuricaemia in adults, especially for normal-weight and lean populations.

Association between snoring frequency and male serum testosterone: Findings from the 2015-2016 National Health and Nutrition Examination Survey

BACKGROUND

This study aimed to assess the association between snoring frequency and male serum testosterone levels.

METHODS

We analyzed data from the 2015 to 2016 National Health and Nutrition Examination Survey. Snoring frequency was relied on self-report, and was divided into never, rarely (1-2 nights a week), occasionally (3-4 nights a week), or frequently (5 or more nights a week) groups. Multivariable analysis controlling for age, race, waist circumference, total cholesterol, diabetes, and hypertension was used to evaluate the association between snoring frequency and male serum testosterone. Furthermore, we performed the subgroup analyses stratified by age and waist circumference.

RESULTS

Our analysis included 1900 participants. In the fully adjusted model, only frequent snoring was inversely associated with male serum testosterone (β -0.053, 95% CI -0.101 to -0.006, P = 0.028); According to the subgroup analysis stratified by age, only in 40-59 years group, frequent snoring was inversely associated with male serum testosterone in the fully adjusted model (β -0.113, 95% CI -0.196 to -0.031, P = 0.007). As for the subgroup analysis stratified by waist circumference, our results showed only in the waist circumference ≥102 cm group (abdominal obesity), frequent snoring was inversely associated with male serum testosterone (β -0.133, 95% CI -0.216 to -0.05, P = 0.002).

CONCLUSIONS

Frequent snoring (5 or more nights a week) is inversely associated with male serum testosterone levels, especially in those aged 40-59 years and those with abdominal obesity.

The Association between Serum Testosterone and Hyperuricemia in Males

Gout is a common systemic inflammatory disease with a male predominance. This study aimed to determine the relationship between serum total testosterone level and hyperuricemia. Data on 1899 men, collected from 2007 to 2017, were included in the analysis. Serum testosterone and urate (SU) were measured on enrolment. The primary endpoints were SU levels ≥ 7 mg/dL and ≥9 mg/dL. On enrolment, participants had a mean age of 45.6 years and mean total testosterone and SU levels of 510 ng/dL and 6.6 mg/dL, respectively. The mean total testosterone levels were 533 and 470 ng/dL in patients with SU levels < 7 mg/dL and ≥7 mg/dL, respectively (p < 0.001); and 515 and 425 ng/dL in patients with SU levels < 9 mg/dL and ≥9 mg/dL, respectively (p < 0.001). After adjusting for age, body mass index, creatinine, serum lipid, fasting blood glucose, systolic blood pressure, and diastolic blood pressure, low testosterone level (<400 ng/dL) was significantly associated with an SU level ≥ 7 mg/dL (hazard ratio: 1.182, 95% confidence interval: 1.005−1.39) and ≥9 mg/dL (hazard ratio: 1.905, 95% confidence interval: 1.239−2.928). In men, a low testosterone level may be associated with an increased risk of hyperuricemia.

The relationship between uric acid and total femur bone mineral density in hypertensive and non-hypertensive populations

OBJECTIVE

This study aimed to explore the association between uric acid (UA) and total femur bone mineral density (BMD) in hypertensive and non-hypertensive groups.

METHODS

We conducted a cross-sectional study of 13,108 participants in the NHANES database, including 4,679 hypertensive and 8,429 non-hypertensive subjects. A weighted multiple linear regression analysis was conducted to explore the association between UA and total femur BMD.

RESULTS

In the hypertensive group, the relationship between UA and total femur BMD was positive [β, 3.02 (95% CI, -0.44 to 6.48), p = 0.0962). In the non-hypertensive group, the association was significantly positive [β, 5.64 (95% CI, 2.06-9.22), p = 0.0038]. In gender-stratified analysis, UA was analyzed as a continuous variable and a categorical variable (quartile). The significantly positive association was present in both the hypertensive male group [β, 5.10 (95% CI, 0.98-9.21), p for trend = 0.0042] and non-hypertensive male group [β, 10.63 (95% CI, 6.32-14.94), p for trend = 0.0001]. A smooth curve fitting showed that in the hypertensive male group, the relationship between UA and total femur BMD was an inverted U-shaped curve. In the hypertensive female group, the relationship was basically negative. In the non-hypertensive population, the relationship between UA and total femur BMD was an inverted U curve in both men and women.

CONCLUSION

In the hypertensive male group, the association between UA and total femur BMD was an inverted U-shaped curve. As to women, the relationship was basically negative. In the non-hypertensive group, the association between UA and total femur BMD was an inverted U-shaped curve in different genders.

The dose-response relationship between sex hormones and hyperuricemia in different gender: NHANES 2013-2016

OBJECTIVES

To access the dose-response relationship between sex hormones and hyperuricemia (HUA), and to find the cut-off value in different gender.

METHODS

9,685 participants were derived from the database of National Health and Nutrition Examination Survey (NHANES). Restricted cubic spline (RCS) analysis were applied to explore the relationship between sex hormones and HUA after adjusting for confounding factors by propensity score match (PSM). Logistic regression was used to estimate the odds ratio (OR) and 95% CI.

RESULTS

The prevalence of HUA was 15.13% in female participants and 22.30% in male participants. Logistic regression analysis showed that estradiol (E2) was independently associated with HUA for a P value of 0.003 and 0.01in female and male participants, respectively. Testosterone (T) was only independently associated with HUA in male participants (P&lt;0.001) but not in female participants (P = 0.59). RCS analysis showed a dose-response relationship between sex hormones and HUA. The risk of HUA increased as E2 lower than 29.6pg/mL in female participants and T lower than 389.1ng/dL in male participants. E2 higher than 23.6pg/ml was an independent risk factor for HUA in male participants.

CONCLUSION

A dose-response relationship was found between sex hormones and HUA. The cut-off value of E2 in male and female participants was 29.6pg/mL and 23.6pg/mL, respectively, and the cut-off value of T in male participants was 389.1ng/dL. These results provide a reference for preventing HUA and hormone supplement therapy.