Endocrine Abstracts

After synthesis in the skin or intake with the diet, vitamin D3 is hydroxylated in the liver to 25-hydroxyvitamin D (25(OH)D), and subsequently in the kidney to 1,25-dihydroxyvitamin D (1,25(OH)2D). The major vitamin D store is the circulating 25(OH)D. The serum 25(OH)D concentration is the measurement of choice to assess the vitamin D status. It is relatively stable and not directly influenced by hormones or calcium in the diet. The half life of serum 25(OH)D is around 25 day...

Background: Oestrogen can increase bone mineral density (BMD) by decreasing bone turnover, which is mainly seen in trabecular bone. Testosterone can increase bone size, but the effect on BMD is less clear. Cross-sex hormonal treatment (CSHT) in transsexuals can therefore affect the BMD. For example, in male-to-female individuals (MtFs) a lower BMD before start of CSHT has been described in comparison to healthy control men.Objectives: To investigate the ...

Introduction: Obesity is associated with lower serum 25-hydroxyvitamin D (25(OH)D) concentrations. A major explanatory hypothesis is that vitamin D is sequestered by adipose tissue. Another hypothesis is a decreased hepatic activation by 25-hydroxylase in obese individuals. Because adipose tissue has different characteristics and functions in different parts of the body an important question is whether serum 25(OH)D is more strongly related to visceral (VAT), hepatic, or total...

Introduction: The current guidelines state that the goals of growth hormone (GH) therapy should be an appropriate clinical response and avoidance of side effects. The target level for IGF1 is commonly the upper half of the reference range, although no published studies offer specific guidance in this regard. Therefore, the aim of the present study is to investigate associations between IGF1 levels within the reference range and several efficacy and safety measures of GH treatm...

Background: Concerns about the effects of gender affirming hormonal treatment (HT) on bone mineral density (BMD) exists, particularly for transmen with decreasing estrogen levels. HT in transpersons affects BMD on short term, but long-term follow-up studies are lacking. Therefore this study aimed to investigate the change in BMD during the first 10 years of HT in adult transwomen and transmen, in order to determine whether it is necessary to assess BMD during HT.<p class="...

Background: Several studies have reported an association between serum 25-hydroxyvitamin D (25(OH)D) concentrations and pulmonary function in the general population. However, results remain conflicting. In addition, the underlying mechanisms by which vitamin D affects pulmonary function are unknown.Objective: To assess the relationship of vitamin D status with pulmonary function and whether this relationship is mediated by physical function and/or inflam...

Introduction: Although vitamin D is well known for its function in calcium homeostasis and bone mineralisation, several studies have shown an effect on physical function and muscle strength. Also, vitamin D has been associated with pulmonary function and the incidence of airway infections. As vitamin D deficiency is highly prevalent in COPD-patients, supplementation might have a beneficial effect in these patients.Objective: To assess the effect of vitam...

Objective: Epidemiological evidence for a link between serum IGF1 concentration and cardiovascular disease in the general population and in patients with GH deficiency or hypersecretion has been demonstrated. However, the underlying mechanisms remain unresolved. We investigated associations between IGF1 levels within the reference range and different measures of cardiovascular function and risk factors in substituted GH deficient adults within a randomized clinical trial.<...

Introduction: Estrogen has positive effects on bone mineral density (BMD), in particular in trabecular bone through inhibition of bone resorption. Testosterone increases bone size, but the effect on BMD is less clear. Cross-sex hormonal treatment (CSHT) in transgender individuals can affect BMD. Therefore, the aim of this study is to investigate effects of CSHT on BMD during the first year of treatment in male-to-female (MtFs) and female-to-male (FtMs) transgender persons....

Sclerostin is a major negative regulator of osteoblastic activity at tissue level. Serum sclerostin levels have been associated with bone mineral density and increased fracture risk. However, the relation between serum levels and expression on tissue levels is unknown. The aim of this study was to investigate this relationship. We used serum samples and bone biopsies from 26 patients that were available from a large randomised clinical trial, investigating with the effect of r...