Effects Of Testosterone Levels Research Articles

The effect of testosterone level on metabolic syndrome: a cross-sectional study.

Metabolic syndrome (MS) may reduce circulating testosterone and, at the same time, low testosterone levels may lead to MS. Thus, identifying problems regarding sex hormones and examining their effects on the pathogenesis of MS is important to prevent serious complications of the condition, such as diabetes or cardiovascular diseases. This study aimed to investigate the correlations between MS-related parameters and androgen levels. A total of 108 males [median age 48.5 years (min/max = 21/77 years)] were included in the study. Blood pressure and anthropometric measurements (body mass index, waist circumference, hip circumference, thigh circumference, neck circumference, and length of index and ring finger) were performed. Biochemical analysis was assessed. Additionally, total testosterone, free testosterone, and sex hormone binding globulin levels were investigated. Weak negativecorrelations were observedbetween testosterone levels and several anthropometric measures/glucose metabolisms (p < 0.05). The highest correlation was between total testosterone levels and body mass index (rho= -0.390, p < 0.001) CONCLUSION: According to our results, controlling weight, one of the preventable risk factors, can have a positive effect on testosterone levels and, therefore, on the cardiovascular system through different mechanisms.

Testosterone and Resting State Connectivity of the Parahippocampal Gyrus in Men With History of Deployment-Related Mild Traumatic Brain Injury.

The purpose of this study was to explore the effect of low testosterone level on whole-brain resting state (RS) connectivity in male veterans with symptoms such as sleep disturbance, fatiguability, pain, anxiety, irritability, or aggressiveness persisting after mild traumatic brain injury (mTBI). Follow-up analyses were performed to determine if sleep scores affected the results. In our cross-sectional design study, RS magnetic resonance imaging scans on 28 veterans were performed, and testosterone, sleep quality, mood, and post-traumatic stress symptoms were measured. For each participant, we computed the average correlation of each voxel's time-series with the rest of the voxels in the brain, then used AFNI's 3dttest++ on the group data to determine whether the effects of testosterone level on whole-brain connectivity were significant. We then performed follow-up region of interest-based RS analyses of testosterone, with and without sleep quality as a covariate. The study protocol was approved by the National Institute of Health's Combined Neuroscience Institutional Review Board. Sixteen participants reported repeated blast exposure in theater, leading to symptoms; the rest reported exposure to a single blast or a nonblast TBI. Thirty-three percent had testosterone levels <300ng/dL. Testosterone level was lower in participants who screened positive for post-traumatic stress disorder compared to those who screened negative, but it did not reach statistical significance. Whole-brain connectivity and testosterone level were positively correlated in the left parahippocampal gyrus (LPhG), especially in its connectivity with frontal areas, the lingual gyrus, cingulate, insula, caudate, and right parahippocampal gyrus. Further analysis revealed that the effect of testosterone on LPhG connectivity is only partially mediated by sleep quality. Sleep quality by itself had an effect on connectivity of the thalamus, cerebellum, precuneus, and posterior cingulate. Lower testosterone levels were correlated with lower connectivity of the LPhG. Weaknesses of this study include a retrospective design based on self-report of mTBI and the lack of a control group without TBI. Without a control group or pre-injury testosterone measures, we were not able to attribute the rate of low testosterone in our participants to TBI per se. Also testosterone levels were checked only once. The high rate of low testosterone level that we found suggests there may be an association between low testosterone level and greater post-traumatic stress disorder symptoms following deployment, but the causality of the relationships between TBI and deployment stress, testosterone level, behavioral symptomatology, and LPhG connectivity remains to be determined. Our study on men with persistent symptoms postdeployment and post-mTBI may help us understand the role of low testosterone and sleep quality in persistent symptoms and may be important in developing therapeutic interventions. Our results highlight the role of the LPhG, as we found that whole-brain connectivity in that region was positively associated with testosterone level, with only a limited portion of that effect attributable to sleep quality.

Effect of Testosterone Level on Mortality in Patients With Left Ventricular Assist Device

Background and objectivesTestosterone deficiency is associated with mortality in patients with heart failure; however, its effects on patients undergoing Left Ventricular Assist Device (LVAD) implantation are unclear. We investigated the role of total testosterone (TT) and free testosterone (FT) levels on mortality undergoing LVAD implantation. MethodsBetween December 2010 and December 2014, 101 consecutive male patients who underwent LVAD implantation and had plasma testosterone measurement (TT and FT) in the last month before operation were included in the study. Demographics, follow-up, and mortality data were analyzed retrospectively. ResultsThe mean age of the patients was 51.7 ± 11 years. TT and FT levels were in the below normal range of 31.6% (n = 32) and 65.3% (n = 66) of the patients, respectively. The mean follow-up time was 355 ± 268 days, and 32 (31%) patients died during follow-up. Cumulative survival rates were significantly worse in patients with low TT and FT than patients in the normal range (P < .001 and P = .029, respectively). Multivariate analysis after adjustment for clinical variables, age, albumin, C-reactive protein, total cholesterol, chronic kidney disease, diabetes mellitus (DM), and leukocytosis showed that low TT and FT were independently associated with poor survival (HR, 3.680; 95% CI, 1.615-8.385 P = .002 and HR, 3.816; 95% CI, 1.279-11.383, P = .016, respectively). ConclusionLow TT and FT levels were independent risk factors for mortality in patients with LVAD.

Testosterone effects on pain and brain activation patterns.

This study investigated whether pain and pain-related unpleasantness ratings were altered by blood testosterone levels. We also investigated whether activation of brain regions that represent pain intensity [primary somatosensory cortex (S1)] and pain-related unpleasantness [perigenual ACC (pACC) and orbitofrontal cortex (OFC)] were affected by blood testosterone levels. Twenty-six healthy men were recruited. Blood testosterone levels were measured before fMRI scanning. The participants were classified into two groups (high vs. low testosterone) according to their blood testosterone level (each group n=13). The middle finger was immersed in a 50°C water bath (50°C, 30s, five times) to induce identical noxious stimulation in all participants. The low testosterone group showed statistically significantly higher pain (P=0.047), unpleasantness (P=0.047), anxiety (P=0.015), and fear ratings (P=0.01) than the high testosterone group. Fear rating increased as pain rating rose and as testosterone level decreased (P<0.001). When participants received noxious stimulation, the pACC and OFC were more highly activated in the low testosterone group compared to the high testosterone group. Activation of S1, a region related to pain intensity, did not differ between both groups. Compared to the high testosterone group, the low testosterone group had significant activation in the pACC and OFC, regions that represent pain-related unpleasantness, but not in S1 that represents pain intensity, leading to higher pain ratings. These findings emphasize the importance of considering the effects of testosterone levels when treating patients.

Effects of Testosterone Level on Lower Urinary Tract Symptoms.

Lower urinary tract symptoms (LUTS) are common in older men and are frequently associated with benign prostatic hyperplasia (BPH). The relationship between BPH and endogenous total testosterone (TT) levels has been widely studied. The aim of this post hoc analysis was to determine the association between LUTS and endogenous TT levels in a subset of men participating in the 2013 Prostate Cancer Awareness Week, a U.S. community-based prostate cancer screening program. Men completed the International Prostate Symptom Score (I-PSS) questionnaire, prostate size was estimated by a digital rectal examination, and serum TT and prostate-specific antigen levels were measured. Mean TT levels (ng/dl) did not significantly correlate with prostate size category (r = +.03, p = .69): normal, 419.2 (n = 106); enlarged, 394.7 (n = 71); abnormal, 416.4 (n = 7); and abnormal/suspicious, 515.2 (n = 19). Mean TT levels (ng/dl) did not significantly correlate with I-PSS category (r = -.06, p = .40): none, 468.5 (n = 15); mild, 414.0 (n = 138); moderate, 397.4 (n = 66); and severe, 437.9 (n = 7). Mean TT levels (ng/dl) did not significantly correlate with I-PSS quality of life rating (r = -.13, p = .055): delighted, 474.5 (n = 43); pleased, 424.6 (n = 65); mostly satisfied, 361.2 (n = 63); mixed, 448.2 (n = 29); mostly dissatisfied, 337.2 (n = 17); and unhappy, 435.8 (n = 6). Adjustment for prostate size or prostate-specific antigen levels yielded similar findings. In conclusion, endogenous TT levels did not correlate with LUTS or prostate size, and these findings support the saturation theory in which TT is not able to induce further androgen-stimulated prostate tissue growth due to receptor saturation. Any worsening of LUTS following testosterone replacement therapy in hypogonadal men may be related to stimulation of prostatic cells previously deprived of testosterone.

Klinefelter syndrome has increased brain responses to auditory stimuli and motor output, but not to visual stimuli or Stroop adaptation.

Klinefelter syndrome (47, XXY) (KS) is a genetic syndrome characterized by the presence of an extra X chromosome and low level of testosterone, resulting in a number of neurocognitive abnormalities, yet little is known about brain function. This study investigated the fMRI-BOLD response from KS relative to a group of Controls to basic motor, perceptual, executive and adaptation tasks. Participants (N: KS = 49; Controls = 49) responded to whether the words “GREEN” or “RED” were displayed in green or red (incongruent versus congruent colors). One of the colors was presented three times as often as the other, making it possible to study both congruency and adaptation effects independently. Auditory stimuli saying “GREEN” or “RED” had the same distribution, making it possible to study effects of perceptual modality as well as Frequency effects across modalities. We found that KS had an increased response to motor output in primary motor cortex and an increased response to auditory stimuli in auditory cortices, but no difference in primary visual cortices. KS displayed a diminished response to written visual stimuli in secondary visual regions near the Visual Word Form Area, consistent with the widespread dyslexia in the group. No neural differences were found in inhibitory control (Stroop) or in adaptation to differences in stimulus frequencies. Across groups we found a strong positive correlation between age and BOLD response in the brain's motor network with no difference between groups. No effects of testosterone level or brain volume were found. In sum, the present findings suggest that auditory and motor systems in KS are selectively affected, perhaps as a compensatory strategy, and that this is not a systemic effect as it is not seen in the visual system.

The interaction of serum testosterone levels and androgen receptor CAG repeat polymorphism on the risk of erectile dysfunction in aging Taiwanese men.

Testosterone has been found to play important roles in men's sexual function. However, the effects of testosterone can be modulated by androgen receptor (AR) CAG repeat polymorphism. It could also contribute to the risk of erectile dysfunction (ED). The aim of this study is to evaluate the interaction of serum testosterone levels and AR CAG repeat polymorphism on the risk of ED in aging Taiwanese men. This cross-sectional data of Taiwanese men older than 40 years were collected from a free health screening held between August 2010 and August 2011 in Kaohsiung city, Taiwan. All participants completed a health questionnaires included five-item version of the International Index of Erectile Function (IIEF-5) and the International Prostate Symptoms Score, received a detailed physical examination and provided 20 cm3 whole blood samples for biochemical and genetic evaluation. The IIEF-5 was used to evaluate ED. Serum albumin, total testosterone (TT), and sex hormone-binding globulin levels were measured. Free testosterone level was calculated. AR gene CAG repeat polymorphism was determined by direct sequencing. Finally, 478 men with the mean age of 55.7 ± 4.8 years were included. When TT levels were above 330 ng/dL, the effect of testosterone level on erectile function seemed to reach a plateau and a significantly negative correlation between AR CAG repeat length and the score of IIEF-5 was found (r = -0.119, p = 0.034). After adjusting for other covariates, the longer AR CAG repeat length was still an independent risk factor for ED in subjects with TT above 330 ng/dL (p = 0.006), but not in TT of 330 ng/dL or below. In conclusion, both serum testosterone levels and AR CAG repeat polymorphism can influence erectile function concomitantly. In subjects with normal TT concentration, those with longer AR CAG repeat lengths have a higher risk of developing ED.

The effect of testosterone levels on Vo2 max in type 2 diabetic patients

Aim: Testosterone levels correlate not only with insulin sensitivity but also with genetic (OXPHOS gene expression) and functional markers of mitochondrial function (VO2max). A decrease of lean body mass and increase in fat mass are observed in hypogonadal men compared with ageand BMI-matched controls. we are to investigate factors associated with low testosterone levels in type 2 diabetic patients, and the effect of testosterone level on body composition and VO2max (exercise capacity). Method: 30 type 2 diabetic patients who’s bood sampling including Total and free testosteronewas donebetween6AMand9 AM.Measuredmetabolic parameterswereHgbA1C, 24hUrine Protein and C-peptide, fasing glucose and insulin for HOMA-IR calculation, lipid profile.Whole body compositionwasmeasuredbyDEXA. VO2max was obtained using an incremental work conducted with a bicycle ergometer combined by continuous analysis of expired gas and minute ventilation. Results: Hypogonadal men had a significantly lower VO2max (ml/kg/min) than eugonadal Men (27.1 vs 30.9: P<0.05). Age had a significant negative relation with testosterone and free testosterone levels. Total fat mass, central fat mass, lean body mass was not signicantly associated with testosterone levels. Total and free testosterone levels did not have any positive effect on insulin resistance index and lipid profile. Rather than total testosterone levels, free testosterone level has amore powerful biologic effect on exercise capacity (VO2max). Conclusion: Age is a sole significant predictor of total and free testosterone levels. Both Total and Free testosterone is not significantly associated with body coposition in type 2 DM. Free testosterone has a more significant biological effect on VO2max. Because significant number of patients had a long disease duration and most patients had been taking medication and/or subcutaneous insulin, HOMA-IR was not significantly associated with VO2max and Testosterone levels.

Effects of gender, cytokine gene polymorphisms and environmental factors on inflammatory responses.

Previous studies have indicated that cytokine gene polymorphisms of Indigenous Australians were predominantly associated with strong pro-inflammatory responses. We tested the hypothesis that cells of donors with genetic profiles of inflammatory cytokine single nucleotide polymorphisms (SNPs) similar to Indigenous Australians produce higher pro-inflammatory responses. PBMCs from 14 donors with genetic profiles for a high risk of strong pro-inflammatory responses and 14 with low-risk profiles were stimulated with endotoxin and effects of gender, IFN-γ, cigarette smoke extract (CSE) and testosterone on cytokine responses analysed. Cytokines were calculated from standard curves (Luminex 2.3 software). No significant differences were associated with SNP profile alone. Lower pro-inflammatory responses were observed for cells from males with low- or high-risk profiles. For cells from females with high-risk profiles, anti-inflammatory IL-10 responses were significantly reduced. There was no effect of testosterone levels on responses from males. For females, results from IFN-γ-treated cells showed positive correlations between testosterone levels and IL-1β responses to endotoxin for both risk groups and TNF-α for the high-risk group. If interactions observed among CSE, IFN-γ, genetic background and testosterone reflect those in vivo, these might contribute to increased incidences of hospitalisations for infectious diseases among Indigenous women.

Effects of testosterone levels on functional recovery with rehabilitation in stroke patients.

The effects of testosterone on functional recovery in stroke patients have not previously been studied. The purpose of the study was to determine the effects of pre-rehabilitation serum testosterone levels on functional recovery in male stroke patients. In total, 111 male stroke patients admitted to our department were enrolled in the study (age: 74 ± 10 years, days from stroke onset: 36 ± 14 days). Serum concentration of free testosterone (Free-T) was measured upon admission. Patients were also evaluated using the Functional Independence Measure (FIM) at admission and discharge. The main outcome variable was FIM at discharge. Correlations between Free-T and FIM were evaluated using Spearman's rank-order correlation coefficients. We performed multivariate linear regression analysis to assess the effects of testosterone on functional outcome with adjustment for patient background variables. In addition, we added a subgroup analysis based on age. The average Free-T serum concentration was 4.7 ± 1.7 pg/ml. There was a significant positive correlation between Free-T and discharge FIM. The multivariate linear regression model showed that Free-T concentration was significantly associated with FIM at discharge (β = 0.09; P = 0.01). In the subgroup analysis, Free-T had significant association with discharge FIM only in patients under 76 years old (β = 0.24; P < 0.001). Our data suggest that serum Free-T levels have a positive effect for discharge FIM in male stroke patients.

Autism and the Technical Mind

The author discusses research into the rate of autistic children born to parents with technical jobs such as engineering. The concept of assortative mating is described, and mate selection in humans, the genetics of autism, and the psychological factors of autism are discussed. Systemizing behavior in autistic children, the mechanical abilities of children with Asperger's syndrome, and the relationship between mathematics ability and autism rates are discussed. The author researched the children of people who work in Silicon Valley in California and Bangalore, India, where there is a concentration of computer researchers, as well as the effect of testosterone levels in pregnant women. INSET: IN BRIEF.

Endogenous Testosterone Levels, Physical Performance, and Fall Risk in Older Men

Gonadal steroid levels decline with age in men. Whether low testosterone levels affect the development of common age-related disorders, including physical functioning and falling, is unclear. This longitudinal, observational follow-up study sought to determine whether low testosterone levels are associated with physical performance and fall risk in older men. A total of 2587 community-based men aged 65 to 99 years were selected using a stratified random sampling scheme from a study cohort of 5995 volunteers. Bioavailable testosterone and estradiol levels and physical performance measures were determined from baseline. Incident falls were ascertained every 4 months during 4 years of follow-up. Generalized estimating equations were used to estimate risk ratios for the relation of sex steroids to falls. Fifty-six percent of the men reported at least 1 fall; many fell frequently. Lower bioavailable testosterone levels were associated with increased fall risk. Men with testosterone levels in the lowest quartile had a 40% higher fall risk than those in the highest quartile. The effect of low testosterone levels was most apparent in younger men (65-69 years) (relative risk, 1.8; 95% confidence interval, 1.2-2.7); testosterone level was not associated with falls in the oldest men (>/=80 years). Lower testosterone concentrations were associated with reduced physical performance. However, the association between low testosterone levels and fall risk persisted despite adjustment for performance. Falls were common among older men. Fall risk was higher in men with lower bioavailable testosterone levels. The effect of testosterone level was independent of poorer physical performance, suggesting that the effect of testosterone on fall risk may be mediated by other androgen actions.