The effects of age and obesity on postprandial dynamics of serum testosterone levels in men.

Objective: Guidelines recommend using fasting samples to evaluate testosterone (T) levels in men, as free and total T levels decrease postprandially. However, it is not clear whether these dynamics are affected by age or obesity. This could be relevant given the obesity epidemic, ageing population and the barrier for screening which fasting could impose.

Bi-allelic Loss-of-Function Mutations in the NPR-C Receptor Result in Enhanced Growth and Connective Tissue Abnormalities.

The natriuretic peptide signaling pathway has been implicated in many cellular processes, including endochondral ossification and bone growth. More precisely, different mutations in the NPR-B receptor and the CNP ligand have been identified in individuals with either short or tall stature. In this study we show that the NPR-C receptor (encoded by NPR3) is also important for the regulation of linear bone growth.

Proandrogenic and Antiandrogenic Progestins in Transgender Youth: Differential Effects on Body Composition and Bone Metabolism.

Context: Progestins can be used to attenuate endogenous hormonal effects in late-pubertal transgender (trans) adolescents (Tanner stage B4/5 and G4/5). Currently, no data are available on the effects of progestins on the development of bone mass or body composition in trans youth.

Objective: To study prospectively the evolution of body composition and bone mass in late-pubertal trans adolescents using the proandrogenic or antiandrogenic progestins lynestrenol (L) and cyproterone acetate (CA), respectively.

Three year functional changes and long-term mortality hazard in community-dwelling older men.

Background: Low levels of physical function have been associated with higher mortality hazard in older persons. However, few studies have investigated the association between functional changes and subsequent mortality. This study aimed to examine whether 3-year functional changes independently predict subsequent all-cause mortality.

Validation of the FNIH sarcopenia criteria and SOF frailty index as predictors of long-term mortality in ambulatory older men.

Objective: we aimed to evaluate the Foundation for the National Institutes of Health (FNIH) criteria for weakness and low muscle mass and the Study of Osteoporotic Fractures (SOF) frailty index for prediction of long-term, all-cause mortality.

Design: community-based cohort study.

Setting: semi-rural community of Merelbeke (Belgium).

Cross-sex hormone therapy in trans persons is safe and effective at short-time follow-up: results from the European network for the investigation of gender incongruence.

Introduction: Data on the effects of cross-sex hormone therapy (CHT) are limited due to the low prevalence of gender dysphoria, small number of subjects treated at each center, lack of prospective studies, and wide variations in treatment modalities.

Aim: The aim of this study is to report the short-term effects of CHT on hormonal and clinical changes, side effects, and adverse events in trans men (female-to-male gender dysphoric persons) and trans women (male-to-female gender dysphoric persons).

Methods: This was a multicenter 1-year prospective study in 53 trans men and 53 trans women.

Short- and long-term clinical skin effects of testosterone treatment in trans men.

Introduction: Our knowledge concerning the effects of testosterone (T) therapy on the skin of trans men (female-to-male transsexuals) is scarce.

Aim: The aim of this study was to evaluate the short- and long-term clinical effects of T treatment on the skin of trans men.

Methods: We conducted a prospective intervention study in 20 hormone naive trans men and a cross-sectional study in 50 trans men with an average of 10 years on T therapy.

Heredity and lifestyle in the determination of between-subject variation in thyroid hormone levels in euthyroid men.

Objective: Variation in thyroid hormone (TH) concentrations between subjects is greater than in a single subject over a prolonged period of time, suggesting an individual set point for thyroid function. We have previously shown that TH levels within normal range are associated with clinical indices such as bone mass, BMI, and heart rate. The aim of this study on young men was therefore to gain insight into the determinants of variation in TH levels among healthy subjects.

Associations between single nucleotide polymorphisms in thyroid hormone transporter genes (MCT8, MCT10 and OATP1C1) and circulating thyroid hormones.

Background: Thyroid hormone (TH) action takes place intracellularly; therefore, transport across the plasma membrane by specific TH transporters, such as MCT8, MCT10 and OATP1C1, is necessary. Several single nucleotide polymorphisms (SNPs) in these genes were reported to be associated with TH concentrations; however, results have been inconsistent.

Methods: Six SNPs in TH transporter genes (rs5937843-G/T and rs6647476-T/C in MCT8, rs14399-C/A in MCT10, rs10444412-C/T, rs10770704-C/T and rs36010656-C/A in OATP1C1) were genotyped in 2 cohorts; one consisting of 2416 men and women aged 35-55 yrs (Asklepios), and the other of 941 men aged 25-45 yrs (Siblos), using KASPar technology.

Long-term evaluation of donor-site morbidity after radial forearm flap phalloplasty for transsexual men.

Introduction: Phalloplasty using the radial forearm flap is currently the most frequently used technique to create the neophallus in transsexual men (formerly described as female-to-male transsexual persons). Although it is considered the gold standard, its main disadvantage is the eventual donor-site morbidity in a young, healthy patient population.

Aim: The study aims to examine the long-term effects of radial forearm flap phalloplasty in transsexual men and to evaluate aesthetic outcome, scar acceptance, bone health, and daily functioning.

Physical function measurements predict mortality in ambulatory older men.

Background: To assess and compare the predictive value of physical function measurements (PFMs) for all-cause mortality in older men and to evaluate the Timed Up and Go test (TUG) as a predictor in subjects with underlying comorbidity.

Design: Observational study of a population-based sample of 352 ambulatory older men aged 71-86 at study baseline. The Rapid disability rating scale-2, 36-Item short form health survey, Grip strength, Five times sit-to-stand test, Standing balance, and TUG were determined at baseline.

Body composition and metabolic parameters are associated with variation in thyroid hormone levels among euthyroid young men.

Objective: Thyroid disorders affect metabolism and body composition. Existing literature has been conflicting on whether this is also the case for thyroid hormone levels within the euthyroid range. Therefore, we have investigated the relationship between thyroid hormone concentrations and body composition together with metabolic parameters in a population of healthy euthyroid men.

Comparative bone status assessment by dual energy X-ray absorptiometry, peripheral quantitative computed tomography and quantitative ultrasound in adolescents and young adults with cystic fibrosis.

Purpose: Quantitative ultrasound bone sonometry (QUS) might be a promising screening method for cystic fibrosis (CF)-related bone disease, given its absence of radiation exposure, portability of the equipment and low cost.The value of axial transmission forearm QUS in detecting osteopenia in CF was therefore studied.

Methods: We investigated the application of QUS in the evaluation of bone status in a group of 64 adolescents (>12 years) and young adults (<40 years) with CF in a comparison with a dual X-ray absorptiometry (DXA) of the whole body and peripheral quantitative computed tomography (pQCT) of the radius at 4% and 66% sites.

Quality of life and sexual health after sex reassignment surgery in transsexual men.

Introduction: Although sexual health after genital surgery is an important outcome factor for many transsexual persons, little attention has been attributed to this subject.

Aims: To provide data on quality of life and sexual health after sex reassignment surgery (SRS) in transsexual men.

Methods: A single-center, cross-sectional study in 49 transsexual men (mean age 37 years) after long-term testosterone therapy and on average 8 years after SRS.

Bivariate association analysis in selected samples: application to a GWAS of two bone mineral density phenotypes in males with high or low BMD.

Our specific aims were to evaluate the power of bivariate analysis and to compare its performance with traditional univariate analysis in samples of unrelated subjects under varying sampling selection designs. Bivariate association analysis was based on the seemingly unrelated regression (SUR) model that allows different genetic models for different traits. We conducted extensive simulations for the case of two correlated quantitative phenotypes, with the quantitative trait locus making equal or unequal contributions to each phenotype.

Anthropometric and skeletal phenotype in men with idiopathic osteoporosis and their sons is consistent with deficient estrogen action during maturation.

Context: Pathophysiology of deficient bone mass acquisition in male idiopathic osteoporosis (IO) remains poorly understood.

Objective: Our objective was to investigate volumetric and geometric parameters of the appendicular skeleton, biochemical markers, and anthropometrics in men with IO.

Design, Setting, And Participants: Our cross-sectional study included 107 men diagnosed with idiopathic low bone mass, 23 of their adult sons, and 130 age-matched controls.

Prevalence of low bone mass in relation to estrogen treatment and body composition in male-to-female transsexual persons.

Bone health is a parameter of interest in the daily follow-up of male-to-female (M --> F) transsexual persons both before and after sex reassignment surgery (SRS) due to an intensely changing hormonal milieu. We have studied body composition, areal, geometric, and volumetric bone parameters, using DXA and peripheral quantitative computed tomography at different sites in 50 M --> F transsexual persons, at least 3 yr after the start of the hormonal treatment and 1 yr after SRS. In this cross-sectional study, hormone levels and markers of bone metabolism were assessed using immunoassays.

Body composition, volumetric and areal bone parameters in male-to-female transsexual persons.

Context: Male-to-female (M-->F) transsexual persons undergo extreme changes in gonadal hormone concentrations, both by pharmacological and surgical interventions. Given the importance of sex steroids for developing and maintaining bone mass, bone health is a matter of concern in daily management of these patients.

Objective: To provide data on bone metabolism, geometry and volumetric bone mineral density in M-->F transsexual persons.

Polymorphisms of the SHBG gene contribute to the interindividual variation of sex steroid hormone blood levels in young, middle-aged and elderly men.

Objective: In men there is a large interindividual variation of SHBG levels and consequently of testosterone (T) and E(2) levels. Family and twin studies suggested a strong genetic contribution, besides metabolic and hormonal influences. The aim of this study was to examine the influence of a missense mutation in exon 8 (Asp327Asn) and a (TAAAA)(n)-repeat in the promoter region of the SHBG gene, on SHBG and sex steroid serum concentrations in a population of healthy men.

Genome-wide linkage screen of bone mineral density (BMD) in European pedigrees ascertained through a male relative with low BMD values: evidence for quantitative trait loci on 17q21-23, 11q12-13, 13q12-14, and 22q11.

Context: Bone mass is under strong genetic control, with heritability estimates greater than 50% and is likely determined by complex interactions between genetic and environmental factors.

Objective: The objective of the study was to localize genes contributing to bone mineral density (BMD) variation.

Design: An autosomal genome-wide scan for BMD at the lumbar spine and femoral neck was conducted with variance components linkage methods.