Bioavailable Testosterone Levels Research Articles

A Mendelian Randomization Study of the Connection Between Exogenous Hormones and Perianal Abscess in Pediatric Patients.

Background: Recent years have witnessed the hypothesis that bioavailable testosterone (BT) might be closely related to the development of inflammatory diseases, especially anal abscess (AA), a common inflammatory ailment with unclear pathogenesis. Given that AA is more prevalent among males, this study investigates the causal relationship between BT and AA. Objective: To explore the causal link between BT and AA, a Mendelian randomization (MR) study was conducted using large-scale genomic data. Materials and Methods: Utilizing genomic data from the UK Biobank and IEU OpenGWAS databases, a two-sample MR analysis was executed. Twenty-six genetic variants strongly associated with BT were selected as instrumental variables (IVs) to assess their link with AA risk. Various MR methods were employed for consistency checks, including sensitivity analyses for heterogeneity and horizontal pleiotropy. Results: Using a combination of MR methods, we identified a significant causal relationship between BT and the risk of AA. Specifically, the MR analysis revealed that higher levels of BT were associated with an increased risk of AA. Sensitivity analyses, including heterogeneity tests and assessments for horizontal pleiotropy, confirmed the robustness of these findings. The IVs used in the analysis demonstrated a strong association with BT and showed no evidence of significant heterogeneity or horizontal pleiotropy, indicating the validity of the causal inference. Conclusion: This study, employing two-sample MR for the first time, confirms a causal relationship between BT levels and the risk of AA. These findings provide preliminary evidence of the causal relationship between BT and AA and may offer new insights into the pathophysiological mechanism of AA and future therapeutic strategies.

8319 Pituitary Apoplexy Leads to the Spontaneous Resolution of Hypercortisolism Secondary to Cushing Disease: A Clinical Case

Abstract Disclosure: N. Sweis: None. J. Sanchez Perez: None. M. Fariduddin: None. R.M. Sargis: None. D.J. Toft: None. S. Reutrakul: None. Background: Pituitary apoplexy is a potentially fatal condition involving the infarction or hemorrhage of the pituitary gland. Rarely, it can occur in the setting of an ACTH-secreting pituitary adenoma. Clinical Case: A 27-year-old female with a past medical history of obesity, spontaneous miscarriages, and amenorrhea presented to the ER with an acute onset frontal headache of throbbing quality, associated with nausea and vomiting. The headache began two days prior, rapidly intensified, and did not improve with oral acetaminophen. CT of the head revealed an enlarged pituitary gland, while neurovascular imaging showed no abnormalities. Her neurologic examination was normal. She denied visual changes, photophobia, neck rigidity, fevers, chills, or recent infections. Furthermore, she endorsed a weight gain of about 40 pounds over the past year despite no change in dietary habits. This was accompanied by amenorrhea, hair thinning, itchy comedonal acne, hirsutism, and a loss of libido. Her physical examination was remarkable for the presence of cushingoid features including violaceous abdominal striae, facial acne, moon facies, a dorsal fat pad, and acanthosis nigricans around the neck and axillae. Pituitary MRI with and without contrast showed an enlarged sellar and suprasellar macroadenoma measuring approximately 2.1x1.4x1.2 cm abutting the optic chiasm. The visualized lesion contained hemorrhagic products, suggesting pituitary apoplexy. Biochemical testing on admission included a low morning plasma cortisol of 6.5 ug/dL (ref. range: 6.7-22.6 ug/dL), a 24-hour urine free cortisol of 12.0 (<=45.0 ug/24 hour), and an elevated ACTH of 145.0 pg/mL (7.2 - 63.3 pg/mL). A1c was 5.8% (<5.7%). Serum levels of prolactin, IGF1, GH, LH, FSH, TSH, Free T4, estradiol, total and bioavailable testosterone were within normal limits. She was evaluated with an ACTH stimulation test, which showed a morning cortisol level of 1.2 ug/dL at baseline, lower from prior. Cortisol levels were adequately increased at 19.6 ug/dL and 22.6 ug/dL, 30 and 60 minutes after the administration of Cosyntropin 250 mcg, respectively (>=18 ug/dL after 30-60 mins). The level of ACTH at the time was also decreased to 76.6 pg/mL. The patient was therefore started on steroid replacement therapy with hydrocortisone and later underwent transsphenoidal resection of the pituitary mass without complications. Histopathological examination of the resected mass showed pituitary adenoma cells with diffuse weak to moderate ACTH staining, most consistent with a sparsely granulated corticotroph pituitary adenoma. Conclusion: We report an interesting case of Cushing disease that spontaneously resolved after pituitary apoplexy. Our case underlines the importance of close monitoring of such patients who may rapidly undergo a period of adrenal insufficiency after hypercortisolism. Presentation: 6/3/2024

6450 Leydig Cell Tumor: A Rare Cause of Post-menopausal Hyperandrogenism

Abstract Disclosure: R. Nakdali: None. S. Athimulam: None. Introduction: Ovarian steroid cell tumors are a rare subtype of sex-cord stromal tumors. Leydig cell tumors is a subtype of sex-stromal tumors that is found in < 1% of all ovarian tumors. They are typically benign, unilateral, and secrete androgens which causes virilization. Below we present the case of a postmenopausal woman who presented with signs of virilization and was diagnosed with an ovarian Leydig cell tumor. Case: A 62-year-old postmenopausal woman, with a history of partial hysterectomy with right oophorectomy presented to Endocrinology clinic for evaluation of thyroid nodules. However, clinically she had signs of virilization noted by the provider on examination. She reported progressive androgenic alopecia, cystic acne, oily skin, hoarseness of voice and hirsutism, with increase hair growth over upper lip, chin and jaw line requiring daily shaving. She denied taking any supplements. She reported embarrassment of these physical changes and prior providers had attributed this to aging, therefore not prompting further testing. This caused significant emotional distress to the patient, leading to isolation. Biochemical testing confirmed elevated bioavailable testosterone (193.1 ng/dL) and total testosterone levels (579 ng/dL), with no evidence of hypercortisolemia. Magnetic resonance imaging (MRI) revealed a heterogenous soft tissue mass (2.9 x 2.1 x 2.1 cm) in the left ovary. She underwent a left salpingo-oophorectomy and pathology confirmed a well-differentiated 2.4 cm Leydig cell tumor. Post-operatively, she reported improvement in facial and body hirsutism, reduced shaving frequency decrease in androgenic hair loss, with noticeable hair growth in her frontal scalp, and her skin became less oily with reduced acne. Post-operative labs confirmed cure of hyperandrogenism (Bioavailable testosterone < 2.6 ng/dL; Total testosterone: < 10ng/dL; and Free androgen index < 0.5%). She has been referred to genetics for evaluation. Discussion: Post-menopausal hyperandrogenism poses a diagnostic challenge as it can be mistaken for hormonal imbalances seen with aging. Often times, patients do not report symptoms due to embarrassment unless specifically addressed by provider. Initial testing consists of total and free testosterone and dehydroepiandrosterone sulfate (DHEAS) levels to assess the source of hyperandrogenism. Ruling out hypercortisolemia and assessment for ingestion of testosterone or DHEA supplements is vital. Pelvic ultrasound or cross-sectional imaging (CT or MRI) of abdomen and pelvis can identify structural abnormalities in the ovaries or adrenal glands. Prompt evaluation and management can alleviate significant distress to the patient. Leydig cell tumors represent a rare but important consideration in the differential diagnosis of postmenopausal hyperandrogenism, such as in our patient. Presentation: 6/2/2024

6450 Leydig Cell Tumor: A Rare Cause of Post-menopausal Hyperandrogenism

Abstract Disclosure: R. Nakdali: None. S. Athimulam: None. Introduction: Ovarian steroid cell tumors are a rare subtype of sex-cord stromal tumors. Leydig cell tumors is a subtype of sex-stromal tumors that is found in < 1% of all ovarian tumors. They are typically benign, unilateral, and secrete androgens which causes virilization. Below we present the case of a postmenopausal woman who presented with signs of virilization and was diagnosed with an ovarian Leydig cell tumor. Case: A 62-year-old postmenopausal woman, with a history of partial hysterectomy with right oophorectomy presented to Endocrinology clinic for evaluation of thyroid nodules. However, clinically she had signs of virilization noted by the provider on examination. She reported progressive androgenic alopecia, cystic acne, oily skin, hoarseness of voice and hirsutism, with increase hair growth over upper lip, chin and jaw line requiring daily shaving. She denied taking any supplements. She reported embarrassment of these physical changes and prior providers had attributed this to aging, therefore not prompting further testing. This caused significant emotional distress to the patient, leading to isolation. Biochemical testing confirmed elevated bioavailable testosterone (193.1 ng/dL) and total testosterone levels (579 ng/dL), with no evidence of hypercortisolemia. Magnetic resonance imaging (MRI) revealed a heterogenous soft tissue mass (2.9 x 2.1 x 2.1 cm) in the left ovary. She underwent a left salpingo-oophorectomy and pathology confirmed a well-differentiated 2.4 cm Leydig cell tumor. Post-operatively, she reported improvement in facial and body hirsutism, reduced shaving frequency decrease in androgenic hair loss, with noticeable hair growth in her frontal scalp, and her skin became less oily with reduced acne. Post-operative labs confirmed cure of hyperandrogenism (Bioavailable testosterone < 2.6 ng/dL; Total testosterone: < 10ng/dL; and Free androgen index < 0.5%). She has been referred to genetics for evaluation. Discussion: Post-menopausal hyperandrogenism poses a diagnostic challenge as it can be mistaken for hormonal imbalances seen with aging. Often times, patients do not report symptoms due to embarrassment unless specifically addressed by provider. Initial testing consists of total and free testosterone and dehydroepiandrosterone sulfate (DHEAS) levels to assess the source of hyperandrogenism. Ruling out hypercortisolemia and assessment for ingestion of testosterone or DHEA supplements is vital. Pelvic ultrasound or cross-sectional imaging (CT or MRI) of abdomen and pelvis can identify structural abnormalities in the ovaries or adrenal glands. Prompt evaluation and management can alleviate significant distress to the patient. Leydig cell tumors represent a rare but important consideration in the differential diagnosis of postmenopausal hyperandrogenism, such as in our patient. Presentation: 6/2/2024

Causal influences of testosterone on brain structure change rate: A sex-stratified Mendelian randomization study.

The impact of testosterone levels on changes in brain structure has been reported. However, it is still unclear which specific brain region could be affected. This study approached Mendelian randomization method to reveal the causal relationship between testosterone levels and the rate of longitudinal structural changes in the brain. The testosterone-related GWAS data were determined from 425,097 European participants. The GWAS data on the rate of longitudinal structural changes in the brain came from the ENIGMA consortium, which included 15,640 all-age participants from 40 longitudinal cohorts. The inverse variance weighted was considered as the main estimate, MR Egger and weighted median methods were used to supplement IVW. A positive correlation was found between total testosterone levels and bioavailable testosterone levels in women and age-independent longitudinal changes in cerebral WM and surface area. The sex hormone-binding globulin levels were found a negative correlation with age-dependent longitudinal structural changes of cortical GM in men. Additionally, we also found that the bioavailable testosterone level in males was negatively associated with the quadratic age-dependent longitudinal change rate in the globus pallidum. We also found estradiol levels and sex hormone-binding globulin levels were negatively associated with the quadratic age-dependent longitudinal change rate of total brain in men. Moreover, we found a positive correlation between total testosterone levels and linear age-dependent longitudinal changes in the hippocampus in both males and females. The testosterone levels in different genders may have varying degrees of causal effects on the structural changes of brain regions. These findings provide evidence for the influence of the brain glandular axis on brain structure, particularly during female brain development.

Sex-specific causal effects of serum sex hormones on COVID-19 susceptibility and severity: Evidence from the UK Biobank and COVID-19 Host Genetics Initiative

BackgroundSeveral hormone therapies, such as androgen receptor signaling inhibition, are being investigated for their potential effectiveness against coronavirus disease 2019 (COVID-19). However, the causal relationships between serum sex hormones and the predisposition to, as well as the severity of, COVID-19, with a particular emphasis on potential gender-specific impacts, remain elusive. MethodsIn this study, using the latest data from the UK Biobank (up to 424,907 individuals) and COVID-19 Host Genetics Initiative (up to 1,878,143 individuals), we conducted a two-sample Mendelian randomization (MR) to systematically assess the sex-specific causal effects of serum sex hormone levels, total testosterone (TT), bioavailable testosterone (BT) in particular, on COVID-19 outcomes. The inverse-variance weighted method was used in the main MR analysis. Furthermore, we additionally performed a series of sensitivity analyses to assess the robustness of MR effect estimates against potential biases caused by invalid genetic variants. ResultsOur MR analysis revealed novel causal associations between bioavailable testosterone and serum estradiol levels, and SARS-CoV-2 infection in women, but not men, except for a suggestive inverse causal association between estradiol levels and COVID-19 severity in men. ConclusionThese novel findings improve our understanding of the sex-specific causal nature of androgen and estrogen in relation to COVID-19 outcomes, and suggest that bioavailable testosterone and estradiol levels may serve as potential therapeutic targets for preventing SARS-CoV-2 infection and improving patient outcomes.

Final Results of the ANDROCAN Study: Histopathological Characteristics and Biochemical Recurrence at 5 Years of Localized Prostate Cancer According to Preoperative Gonadal Status

Background and objectiveFailure rates after first-line treatment of localized prostate cancer (PCa) treatment remain high; therefore, it is essential to improve the selection and identification of at-risk patients to reduce mortality. The aim of the ANDROCAN study was to evaluate the biochemical recurrence (BCR) in patients with localized PCa treated by total prostatectomy at 5 yr after surgery, according to their presurgery gonadal status. MethodsA prospective cohort study was conducted including 1318 patients undergoing total prostatectomy for localized PCa with a 5-yr postoperative follow-up. Clinical and hormonal data (assays of total testosterone [TT], bioavailable testosterone [BT], dihydrotestosterone, estrone, and estradiol were performed by gas chromatography/mass spectrometry) as well as metabolic syndrome parameters were collected at baseline before surgery. Pathological data (predominant Gleason grade 4 and stage) were collected and cross-referenced centrally. Factors associated with BCR were assessed by a multivariate analysis, and BCR-free survival was assessed by a Kaplan-Meier analysis. Key findings and limitationsAmong the 1318 patients, 237 had BCR of PCa. Considering demographic characteristics, populations with and without BCR were similar. However, patients with BCR had cancers with a higher Gleason score (p = 0.0001) and higher prostate-specific antigen (PSA) values (p = 0.0005) at baseline. Gleason score, pT >3a, and PSA level at baseline were positively correlated with BCR (p < 0.0001, p < 0.0001, and p = 0.0048, respectively), while BT and TT levels were not associated with BCR. This study includes patients with varying clinical characteristics, such as cancer history and metabolic syndrome, introducing variability that makes it challenging to isolate the specific effects of gonadal status on BCR. Another limitation is the lack of evaluation of long-term BCR beyond 5 yr, potentially overlooking recurrences that occur between 5 and 15 yr after surgery. This could lead to an underestimation of the actual long-term recurrence rates. Conclusions and clinical implicationsOverall, PSA levels, high Gleason score, and pT >3a are associated with a greater likelihood of disease recurrence following initial treatment and could serve as important prognostic indicators for predicting the risk of BCR. In this prospective study, biochemical hypogonadism was not associated with a higher occurrence of BCR within 5 yr of prostatectomy. The biological gonadal status of preoperative patients could potentially be useful for therapeutic decisions but does not provide an indication for the oncological follow-up. Patient summaryFive-year follow up of patients after surgery showed that there is no association between hypogonadism (low levels of total testosterone and bioavailable testosterone) and cancer recurrence. However, cancer recurrence seems to be more associated with aggressiveness of cancer at the time of detection.

Association between levels of sex hormones and risk of multiple sclerosis: a mendelian randomization study.

This research aimed to examine the causal connections between multiple sclerosis (MS) and a range of sex hormone-related traits, such as bioavailable testosterone (BT), sex hormone-binding globulin (SHBG), testosterone, and estradiol (E2). A bidirectional two-sample Mendelian randomization (MR) analysis using summary statistics from genome-wide association studies (GWAS) was conducted to investigate the relationship between sex hormone-related traits and MS. Moreover, the Inverse-variance weighted (IVW) method was employed as the primary analysis approach. The MR analysis, using the IVW method, found a significant correlation between genetically determined SHBG levels and MS (OR = 1.634, 95% CI: 1.029-2.599, p = 0.038). Similarly, the reverse MR analysis suggested a causal link between MS and SHBG (OR = 1.005, 95% CI: 1.001-1.009, P = 0.003). However, no association was observed between MS risk and E2, testosterone, or BT levels. Our MR analysis demonstrated that genetically predicted higher SHBG may be positively correlated with the risk of MS. Moreover, the role of SHBG in MS could be further investigated.

Increase in Testosterone Levels and Improvement of Clinical Symptoms in Eugonadic men With a Prolactin-secreting Adenoma.

Testosterone concentrations, albeit rarely, may be in the normal range (>3.0 ng/mL) in men with a prolactin-secreting pituitary adenoma (PSPA-nt). The evolution of total, bioavailable testosterone, gonadotropin levels, and that of graded symptoms of testosterone deficiency (TD) are uncertain in these patients. Retrospective case-control longitudinal study at a tertiary referral center. From 287 men, we selected 25 PSPA-nt men undergoing prolactin normalization (<20.0 ng/mL) during the follow-up. Graded symptoms of TD were investigated by structured interviews. Biochemical changes and TD symptoms were compared to those of a matched cohort of 61 men with pituitary neoplasms and normal testosterone levels (PA-nt). Baseline testosterone levels were similar between PSPA-nt and PA-nt subjects. The prevalence of specific and suggestive symptoms of TD was higher in PSPA-nt (20% and 68%) than in PAnt (3.3 and 29.5%; P = .02 and P = .0015, respectively). At the follow-up, total and bioavailable testosterone levels increased in PSPA-nt but not in PA-nt patients (Δ change: 1.28 ± 2.1 vs0.03 ± 1.5 ng/mL, + 0.33 ± 0.55 vs-0.26 ± 0.60 ng/mL; P = .0028 and P = .0088, respectively). LH and FSH levels also increased in PSPA-nt men (P < .05). Specific and suggestive, but not nonspecific symptoms of TD, improved only in PSPA-nt men (P < .05 for both). Baseline testosterone and LH were the strongest predictors of testosterone improvement in PSPA-nt patients. Despite having normal testosterone levels at baseline, patients with PSPA-nt experience a relief of TD symptoms and an improvement of their pituitary-gonadal axis function following prolactin normalization, especially when baseline TT and LH levels are in the low-normal range.

High bioavailable testosterone levels increase the incidence of isolated REM sleep behavior disorder: Results from multivariable and network Mendelian randomization analysis

ObjectivesTo explore the causal relationships between sex hormone levels and incidence of isolated REM sleep behavior disorder (iRBD). MethodsIn our study, we utilized Genome-Wide Association Studies (GWAS) data for iRBD, including 9447 samples with 1061 cases of iRBD provided by the International RBD Study Group. Initially, we conducted a two-sample univariate MR analysis to explore the impact of sex hormone-related indicators on iRBD. This was followed by the application of multivariable MR methods to adjust for other hormone levels and potential confounders. Finally, we undertook a network MR analysis, employing brain structure Magnetic Resonance Imaging (MRI) characteristics as potential mediators, to examine whether sex hormones could indirectly influence the incidence of iRBD by affecting brain structure. ResultsBioavailable testosterone (BioT) is an independent risk factor for iRBD (Odds Ratio [95 % Confidence Interval] = 2.437 [1.308, 4.539], P = 0.005, corrected-P = 0.020), a finding that remained consistent even after adjusting for other sex hormone levels and potential confounders. Additionally, BioT appears to indirectly increase the risk of iRBD by reducing axial diffusivity and increasing the orientation dispersion index in the left cingulum and cingulate gyrus. ConclusionsOur research reveals that elevated levels of BioT contribute to the development of iRBD. However, the specific impact of BioT on different sexes remains unclear. Furthermore, high BioT may indirectly lead to iRBD by impairing normal pathways in the left cingulum and cingulate gyrus and fostering abnormal pathway formation.

Effects of Testosterone in Mediating the Relationship Between Daytime Napping and Osteoporosis in European Populations: A Mendelian Randomization Study.

We aimed to explore the causal effect of daytime napping on the risk of osteoporosis and the mediation role of testosterone in explaining this relationship. Summary data for Mendelian randomization (MR) analysis were obtained from the IEU OpenGWAS database. Univariable MR(UVMR) analysis and multiple sensitivity analyses were applied to explore the casual relationship between daytime napping and bone mineral density (BMD)/osteoporosis. We also conducted multivariable Mendelian randomization (MVMR) analysis to evaluate the correlation between testosterone-associated single-nucleotide variations and BMD/osteoporosis. Then, mediation analysis was performed to explore whether the association between daytime napping and BMD/osteoporosis was mediated via testosterone. Genetically predicted daytime napping was significantly associated with femoral neck BMD (β [95% CI]: 0.2573 [0.0487, 0.4660];P = 0.0156), lumbar spine BMD (β [95% CI]: 0.2526 [0.0211, 0.4840];P = 0.0324), and osteoporosis (OR [95% CI]: 0.5063 [0.2578, 0.9942];P = 0.0481). β and 95%CIs indicate the standard deviation (SD) unit of BMD increase per category increase in daytime napping. OR and 95%CIs represent the change in the odds ratio of osteoporosis per category increase in daytime napping. We observed a potentially causal effect of more frequent daytime nappingon higher BMD and a lower risk of osteoporosis. Daytime napping was causally associated with a higher level of bioavailable testosterone (β [95% CI]: 0.1397 [0.0619, 0.2175]; P = 0.0004). β and 95%CIs represent the change in the SD of testosterone per category increase in daytime napping. Furthermore, the causal effects of daytime napping on BMD/osteoporosis were partly mediated by bioavailable testosterone. Daytime napping can efficiently increase BMD and reduce the risk of osteoporosis, and testosterone plays a key mediating role in this process.

The impact of obesity and sexual behavior on prostate cancer risk is mediated by testosterone levels: a mendelian randomization study and mediation analysis

BackgroundThe relationship between obesity, sexual behavior, and prostate cancer (PCa) has been widely debated, contributing to a lack of understanding of its potential mechanisms and hindering the development of effective prevention measures. PurposeThe aim of this study was to examine the causal effect of body mass index (BMI), age at first sexual intercourse (AFS), and bioavailable testosterone levels on PCa while also quantifying the potential roles of mediators. MethodWe conducted a Mendelian randomization (MR) study using summary statistics from genome-wide associations of BMI (152,893 European males), AFS (182,791 European males), bioavailable testosterone (184,205 European males), and PCa (79,148 cases, 61,106 controls, European ancestry). Inverse-variance weighted method, weighted median method, MR-Egger regression, Least Absolute Shrinkage and Selection Operator (LASSO), and outlier test were used for MR analyses. Reverse MR and mediation analysis were performed. Data analyses were conducted from December 2022 to July 2023. ResultsThe results showed that genetic liability to BMI was protective of PCa (OR, 0.82; 95% CI: 0.74-0.91; P = 3.29 × 10−4). Genetic liability to later AFS (OR, 1.28; 95% CI: 1.08-1.53; P = 5.64 × 10−3) and higher bioavailable testosterone levels (OR = 1.11, 95% CI: 1.01–1.24, P = 0.04) were associated with an increased risk of PCa. All of these potential causal effects could only be forwarded and were not affected by prostate specific antigen (PSA) screening. After controlling for bioavailable testosterone levels, the causal impact of BMI and AFS on PCa was no longer significant. The mediation analysis suggested that the causal influence of AFS/BMI on PCa relied on bioavailable testosterone levels. ConclusionIn conclusion, the difference between the univariable and multivariable MR results suggested that the causal influence of BMI and AFS on PCa relied on bioavailable testosterone levels. Further work is needed to identify other risk factors and to elucidate the specific mechanisms that underlie this causal pathway.

Association of sleep traits with male fertility: a two-sample Mendelian randomization study.

Background: Previous observational studies have investigated the association between sleep-related traits and male fertility; however, conclusive evidence of a causal connection is lacking. This study aimed to explore the causal relationship between sleep and male fertility using Mendelian randomisation. Methods: Eight sleep-related traits (chronotype, sleep duration, insomnia, snoring, dozing, daytime nap, oversleeping, and undersleeping) and three descriptors representing male fertility (male infertility, abnormal sperm, and bioavailable testosterone levels) were selected from published Genome-Wide Association Studies. The causal relationship between sleep-related traits and male fertility was evaluated using multiple methods, including inverse variance weighting (IVW), weighted median, Mendelian randomisation-Egger, weighted model, and simple model through two-sample Mendelian randomisation analysis. Mendelian randomisation-Egger regression was used to assess pleiotropy, Cochrane's Q test was employed to detect heterogeneity, and a leave-one-out sensitivity analysis was conducted. Results: Genetically-predicted chronotype (IVW,OR = 1.07; 95%CL = 1.04-1.12; p = 0.0002) was suggestively associated with bioavailable testosterone levels. However, using the IVW method, we found no evidence of a causal association between other sleep traits and male fertility. Conclusion: This study found that chronotype affects testosterone secretion levels. However, further studies are needed to explain this mechanism.

Association between ethylene oxide exposure and sex steroid hormone levels in male adults in the United States

Sex steroid hormones play important roles in maintaining our health systems, including reproductive function and developmental health. Ethylene oxide (EtO) is a reactive organic compound that is widely used in the gas sterilization of materials such as foods, spices, and medical devices. Previous studies have suggested that EtO exposure is associated with carcinogenic risk, neurotoxicity, and reproductive toxicity. However, no studies focusing on the relationship between EtO exposure and changes in sex steroid hormone levels have been performed in human. The present study investigated the association between blood EtO levels and serum sex steroid hormone levels in 1,635 adult men from the NHANES 2013-2016. Multivariate linear regression analyses, a positive correlation between blood EtO and total testosterone levels, and the testosterone to estradiol ratio. Moderate EtO exposure was associated with a decrease in estradiol levels, but no relationship was found at the highest exposure range. No significant associations were observed between EtO exposure and free testosterone, bioavailable testosterone, or sex hormone-binding globulin levels. These findings suggest EtO exposure could impact human sex steroid hormone production, although analysis in females and further verification through prospective studies should be performed.

Hepcidin Reduction during Testosterone Therapy in Men with Type 2 Diabetes: A Randomized, Double-Blinded, Placebo-Controlled Study.

A randomized, placebo-controlled, double-blinded study at an academic tertiary-care medical center. Interventions were testosterone gel (TRT, n = 20) or placebo gel (n = 19) for 24 weeks. We included 39 men (50-70 years) with type 2 diabetes (T2D) on metformin monotherapy with bioavailable testosterone levels <7.3 nmol/L. Body composition was assessed with DXA- and MRI-scans; the main study outcomes were serum hepcidin-iron, FGF23, phosphate, klotho, and calprotectin. Hepcidin levels decreased during TRT (β = -9.5 ng/mL, p < 0.001), lean body mass (β = 1.9 kg, p = 0.001) increased, and total fat mass (β = -1.3 kg, p = 0.009) decreased compared to placebo. Delta hepcidin was not associated with changes in lean body mass or fat mass. Iron and the pathways of FGF23-phosphate-klotho and calprotectin were unchanged during TRT. During TRT, the reduction in hepcidin was not associated with circulating iron levels, lean body mass, or fat mass; these findings suggested a direct anti-inflammatory effect of TRT and no indirect effect mediated through these factors.

Is testosterone deficiency a predictive factor for recurrence of urethral stricture?

Testosterone plays a vital role in maintaining tissue homeostasis, and testosterone deficiency may potentially influence the likelihood of urethral stricture recurrence. To evaluate the prognostic value of testosterone levels in the recurrence after direct visual internal urethrotomy in primary short segment bulbar urethral strictures and its clinical reflections. A total of 723 patients who underwent direct vision internal urethrotomy between January 2000 and October 2022 were retrospectively analyzed. After implying exclusion criteria, 116 patients with available data were enrolled. Patients were divided into two groups as recurrence and no recurrence. Age, stricture length, etiology, time of recurrence, diagnosis of previous diabetes mellitus, hypertension, smoking, body mass index, and total testosterone levels were recorded. Free testosterone and bioavailable testosterone values were calculated using total testosterone, albumin, and sex hormone binding globulin values. Hypogonadism was considered as a total testosterone level less than 300ng/dL. Demographic characteristics and total testosterone, free testosterone, and bioavailable testosterone levels were compared between the two groups for statistical significance. The recurrence rates of patients with and without hypogonadism were compared. Recurrence was observed in 41.4% of the cases (n=48). There was no statistically significant difference between the groups in terms of age, body mass index values, diabetes mellitus, hypertension, smoking status, presence of hypogonadism, and etiology (p=0.745, 0.863, 0.621, 0.622, 0.168, 0.051, and 0.232). In terms of total testosterone levels and bioavailable testosterone levels, the recurrence group had significantly lower values (p=0.018 and 0.04). There was no significant difference between the two groups in terms of stricture length (p=0.071). Sixteen of 28 patients with hypogonadism had recurrence, whereas 32 of 88 patients without hypogonadism had recurrence (p=0.051). Testosterone levels have potential to predict recurrence in primary short-segment bulbar urethral strictures. This study represents the inaugural analysis of the impact of testosterone deficiency on recurrence within the cohort of patients with primary short-segment bulbar urethral strictures. Testosterone levels and ratios may serve as predictive factors for identifying recurrent cases in primary short-segment bulbar strictures. For patients at a higher risk of recurrence, urethroplasty may be considered as an initial treatment option, even in cases of primary and short-segment strictures.

Associations between genetically predicted sex and growth hormones and facial aging in the UK Biobank: a two-sample Mendelian randomization study.

Aging is an inescapable process, but it can be slowed down, particularly facial aging. Sex and growth hormones have been shown to play an important role in the process of facial aging. We investigated this association further, using a two-sample Mendelian randomization study. We analyzed genome-wide association study (GWAS) data from the UK Biobank database comprising facial aging data from 432,999 samples, using two-sample Mendelian randomization. In addition, single-nucleotide polymorphism (SNP) data on sex hormone-binding globulin (SHBG) and sex steroid hormones were obtained from a GWAS in the UK Biobank [SHBG, N = 189,473; total testosterone (TT), N = 230,454; bioavailable testosterone (BT), N = 188,507; and estradiol (E2), N = 2,607)]. The inverse-variance weighted (IVW) method was the major algorithm used in this study, and random-effects models were used in cases of heterogeneity. To avoid errors caused by a single algorithm, we selected MR-Egger, weighted median, and weighted mode as supplementary algorithms. Horizontal pleiotropy was detected based on the intercept in the MR-Egger regression. The leave-one-out method was used for sensitivity analysis. SHBG plays a promoting role, whereas sex steroid hormones (TT, BT, and E2) play an inhibitory role in facial aging. Growth hormone (GH) and insulin-like growth factor-1 (IGF-1) levels had no significant effect on facial aging, which is inconsistent with previous findings in vitro. Regulating the levels of SHBG, BT, TT, and E2 may be an important means to delay facial aging.

FRI430 A Case Of Elevated Sex Hormone-binding Globulin Secondary To Variegate Porphyria In A Patient With Hypogonadotropic Hypogonadism

Abstract Disclosure: J. Law: None. C. Yip: Research Investigator; Self; Eli Lilly &amp; Company. Background: Acute porphyria is a group of disorders characterized by enzymatic defects in the heme biosynthetic pathway. The liver is the source of both acute intermittent porphyria (AIP) and variegate porphyria. AIP is known to cause an elevation in sex hormone-binding globulin (SHBG) levels, likely secondary to impaired hepatic function and hepatocyte abnormalities1. We describe a case of elevated SHBG secondary to variegate porphyria, in a male with hypogonadotropic hypogonadism. Case Report: A 44-year-old male presented with an elevated SHBG and symptoms of hypogonadism with low libido, weakness, and fatigue. Fasting morning bloodwork revealed an elevated SHBG at 89 nmol/l (13.5- 71.0), a normal total testosterone level at 12.95 nmol/l (8-32), and a low bioavailable testosterone at 0.82 nmol/l (2.5-10), with confirmatory repeat blood work. His history was significant for longstanding variegate porphyria, manifesting as frequent attacks of abdominal pain. He was on opioids for greater then 10 years for his chronic pain, as well as metoclopramide. On assessment of causes for his elevated SHBG, his TSH was normal at 1.49 mIU/L (0.35-4.30). He did not have cirrhosis, hepatitis, hereditary hemochromatosis, and was not on anticonvulsants. No other cause was found, and his elevated SHBG was deemed secondary to his variegate porphyria. His normal total testosterone level was due to his elevated SHBG, but as mentioned, his bioavailable testosterone was low. His LH and FSH were both inappropriately normal, with his LH being 4.67 IU/L (0.6-12.0) and his FSH 4.7 IU/L (1.0-12.0), in keeping with hypogonadotropic hypogonadism. He went through normal pubertal development and had no anosmia. Workup revealed an elevated prolactin level of 73.8 ug/l (3.5-19.4). He had no galactorrhea or gynecomastia and an MRI sella revealed a normal pituitary gland. His elevated prolactin level was determined to be secondary to his opioid medication and/or metoclopramide use. His hypogonadotropic hypogonadism was deemed secondary to his opioid medications and/or hyperprolactinemia. Conclusion: This case demonstrated variegate porphyria as a likely cause of elevated SHBG, similar to AIP. In patients with variegate porphyria and symptoms of hypogonadism, the SHBG should be measured and if it is elevated, the bioavailable or free testosterone levels should be used in assess instead of relying on the total testosterone levels. As has been previously shown, this case also illustrated the use of opioid medications as a cause of hypogonadotropic hypogonadism.

Association between genetically proxied HMGCR inhibition and male reproductive health: A Mendelian randomization study.

The causal associations between statin use and male sex hormone levels and related disorders have not been fully understood. In this study, we employed Mendelian randomization for the first time to investigate these associations. In two-sample Mendelian randomization framework, genetic proxies for hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) inhibition were identified as variants in the HMGCR gene that were associated with both levels of gene expression and low density lipoprotein cholesterol (LDL-C). We assessed the causal relationship between HMGCR inhibitor and 5 sex hormone levels/2 male-related diseases. Additionally, we investigated the association between 4 circulating lipid traits and outcomes. The "inverse variance weighting" method was used as the primary approach, and we assessed for potential heterogeneity and pleiotropy. In a secondary analysis, we revalidated the impact of HMGCR on 7 major outcomes using the summary-data-based Mendelian randomization method. Our study found a significant causal association between genetic proxies for HMGCR inhibitor and decreased levels of total testosterone (TT) (LDL-C per standard deviation = 38.7mg/dL, effect = -0.20, 95% confidence interval [CI] = -0.25 to -0.15) and bioavailable testosterone (BT) (effect = -0.15, 95% CI = -0.21 to -0.10). Obesity-related factors were found to mediate this association. Furthermore, the inhibitor were found to mediate a reduced risk of prostate cancer (odds ratio = 0.81, 95%CI = 0.7-0.93) by lowering bioavailable testosterone levels, without increasing the risk of erectile dysfunction (P = .17). On the other hand, there was a causal association between increased levels of LDL-C, total cholesterol, triglycerides (TG) and decreased levels of TT, sex hormone-binding globulin, and estradiol. The use of HMGCR inhibitor will reduce testosterone levels and the risk of prostate cancer without the side effect of erectile dysfunction. LDL-C, total cholesterol, and TG levels were protective factors for TT, sex hormone-binding globulin, and estradiol.

Assessing the Casual Association between Sex Hormone Levels and Fracture Risk: A Two-Sample Mendelian Randomization Study.

Prior observational studies have reported that levels of sex hormones constitute a risk factor for the fracture. The aim of this study was to ascertain whether there is a causal relationship between the levels of sex hormones and the risk of fracture through Mendelian randomization (MR). Single-nucleotide polymorphisms (SNPs) associated with two indicators of sex hormone levels, circulating sex hormone-binding globulin (SHBG) and bioavailable testosterone levels, as exposures were selected from a large genome-wide association study (GWAS) from UK Biobank. The summary statistics for 11 different types of fracture as outcomes from the FinnGen consortium. This study employed the two-sample MR approach. For the main analysis, the inverse-variance-weighted (IVW) method was utilized. To assess the heterogeneity of MR results, the IVW method and MR-Egger method were utilized. To evaluate potential pleiotropy, MR-Egger regression was conducted. Additionally, a leave-one-SNP-out test was performed to assess the robustness of MR results to the exclusion of any individual SNP. The MR analyses demonstrated a conspicuous impact of SHBG on the risk of pathological fracture with osteoporosis (OP). We found that an increase of one standard deviation (SD) in SHBG correspondingly increased the risk of pathological fracture with OP [odds ratio (OR) 2.42, 95% confidence interval (CI), 1.52-3.85; p = 1.93 × 10-4 ]. The bioavailable testosterone showed the negative casual genetic associations with fractures of foot and forearm. An increase of one SD in the genetically predetermined bioavailable testosterone was associated with a reduction of 37% in the risk of fracture of foot (OR 0.63, 95% Cl 0.49 to 0.81; p = 3.37 × 10-4 ), as well as a 39% decrease in the risk of fracture of forearm (OR 0.61, 95% Cl 0.50 to 0.76; p = 5.40 × 10-6 ). Our study confirms that individuals experiencing elevated SHBG concentrations showed a major causal effect on pathological fracture with OP. High bioavailable testosterone levels play an important role in preventing the fractures of foot and forearm. Although increasing bioavailable testosterone and decreasing SHBG levels had no casual effect on most fractures in the general population, they are likely to have the most clinically relevant effect on certain fracture risk reduction.