Lars Sävendahl

Consensus Statement: Global Consensus Recommendations on Prevention and Management of Nutritional Rickets

BACKGROUND Vitamin D and calcium deficiencies are common worldwide, causing nutritional rickets and osteomalacia, which have a major impact on health, growth, and development of infants, children, and adolescents; the consequences can be lethal or can last into adulthood. The goals of this evidence-based consensus document are to provide health care professionals with guidance for prevention, diagnosis, and management of nutritional rickets and to provide policy makers with a framework to work toward its eradication. EVIDENCE A systematic literature search examining the definition, diagnosis, treatment, and prevention of nutritional rickets in children was conducted. Evidence-based recommendations were developed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system that describe the strength of the recommendation and the quality of supporting evidence. PROCESS Thirty-three nominated experts in pediatric endocrinology, pediatrics, nutrition, epidemiology, public health, and health economics evaluated the evidence on specific questions within five working groups. The consensus group, representing 11 international scientific organizations, participated in a multiday conference in May 2014 to reach a global evidence-based consensus. RESULTS This consensus document defines nutritional rickets and its diagnostic criteria and describes the clinical management of rickets and osteomalacia. Risk factors, particularly in mothers and infants, are ranked, and specific prevention recommendations including food fortification and supplementation are offered for both the clinical and public health contexts. CONCLUSION Rickets, osteomalacia, and vitamin D and calcium deficiencies are preventable global public health problems in infants, children, and adolescents. Implementation of international rickets prevention programs, including supplementation and food fortification, is urgently required.

Global Consensus Recommendations on Prevention and Management of Nutritional Rickets

Background: Vitamin D and calcium deficiencies are common worldwide, causing nutritional rickets and osteomalacia, which have a major impact on health, growth, and development of infants, children, and adolescents; the consequences can be lethal or can last into adulthood. The goals of this evidence-based consensus document are to provide health care professionals with guidance for prevention, diagnosis, and management of nutritional rickets and to provide policy makers with a framework to work toward its eradication. Evidence: A systematic literature search examining the definition, diagnosis, treatment, and prevention of nutritional rickets in children was conducted. Evidence-based recommendations were developed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system that describes the strength of the recommendation and the quality of supporting evidence. Process: Thirty-three nominated experts in pediatric endocrinology, pediatrics, nutrition, epidemiology, public health, and health economics evaluated the evidence on specific questions within five working groups. The consensus group, representing 11 international scientific organizations, participated in a multiday conference in May 2014 to reach a global evidence-based consensus. Results: This consensus document defines nutritional rickets and its diagnostic criteria and describes the clinical management of rickets and osteomalacia. Risk factors, particularly in mothers and infants, are ranked, and specific prevention recommendations including food fortification and supplementation are offered for both the clinical and public health contexts. Conclusion: Rickets, osteomalacia, and vitamin D and calcium deficiencies are preventable global public health problems in infants, children, and adolescents. Implementation of international rickets prevention programs, including supplementation and food fortification, is urgently required.

Interleukin-1β and TNF-α Act in Synergy to Inhibit Longitudinal Growth in Fetal Rat Metatarsal Bones†

We hypothesized that pro‐inflammatory cytokines can act locally in the growth plate to impair longitudinal growth. In a model of cultured fetal rat metatarsal bones, we found that IL‐1β and TNF‐α act in synergy to inhibit longitudinal growth, an effect linked to decreased proliferation and increased apoptosis of growth plate chondrocytes. IGF‐I could partially reverse all these effects.

Long-term mortality and causes of death in isolated GHD, ISS, and SGA patients treated with recombinant growth hormone during childhood in Belgium, The Netherlands, and Sweden: preliminary report of 3 countries participating in the EU SAGhE study

CONTEXT The long-term mortality in adults treated with recombinant GH during childhood has been poorly investigated. Recently released data from the French part of the European Union Safety and Appropriateness of GH treatments in Europe (EU SAGhE) study have raised concerns on the long-term safety of GH treatment. OBJECTIVE To report preliminary data on long-term vital status and causes of death in patients with isolated GH deficiency or idiopathic short stature or born small for gestational age treated with GH during childhood, in Belgium, The Netherlands, and Sweden. DESIGN Data were retrieved from national registries of GH-treated patients and vital status from National Population Registries. Causes of death were retrieved from a National Cause of Death Register (Sweden), Federal and Regional Death Registries (Belgium), or individual patient records (The Netherlands). PATIENTS All patients diagnosed with isolated GH deficiency or idiopathic short stature or born small for gestational age started on recombinant GH during childhood from 1985-1997 and who had attained 18 yr of age by the end of 2010 were included. Vital status was available for approximately 98% of these 2,543 patients, corresponding to 46,556 person-years of observation. MAIN OUTCOME MEASURE Vital status, causes of death, age at death, year of death, duration of GH treatment, and mean GH dose during treatment were assessed. RESULTS Among 21 deaths identified, 12 were due to accidents, four were suicides, and one patient each died from pneumonia, endocrine dysfunction, primary cardiomyopathy, deficiency of humoral immunity, and coagulation defect. CONCLUSIONS In these cohorts, the majority of deaths (76%) were caused by accidents or suicides. Importantly, none of the patients died from cancer or from a cardiovascular disease.

Osteoblast-derived WNT16 represses osteoclastogenesis and prevents cortical bone fragility fractures.

The WNT16 locus is a major determinant of cortical bone thickness and nonvertebral fracture risk in humans. The disability, mortality and costs caused by osteoporosis-induced nonvertebral fractures are enormous. We demonstrate here that Wnt16-deficient mice develop spontaneous fractures as a result of low cortical thickness and high cortical porosity. In contrast, trabecular bone volume is not altered in these mice. Mechanistic studies revealed that WNT16 is osteoblast derived and inhibits human and mouse osteoclastogenesis both directly by acting on osteoclast progenitors and indirectly by increasing expression of osteoprotegerin (Opg) in osteoblasts. The signaling pathway activated by WNT16 in osteoclast progenitors is noncanonical, whereas the pathway activated in osteoblasts is both canonical and noncanonical. Conditional Wnt16 inactivation revealed that osteoblast-lineage cells are the principal source of WNT16, and its targeted deletion in osteoblasts increases fracture susceptibility. Thus, osteoblast-derived WNT16 is a previously unreported key regulator of osteoclastogenesis and fracture susceptibility. These findings open new avenues for the specific prevention or treatment of nonvertebral fractures, a substantial unmet medical need.

The role of the G protein-coupled receptor GPR30 in the effects of estrogen in ovariectomized mice

In vitro studies suggest that the membrane G protein-coupled receptor GPR30 is a functional estrogen receptor (ER). The aim of the present study was to determine the possible in vivo role of GPR30 as a functional ER primarily for the regulation of skeletal parameters, including bone mass and longitudinal bone growth, but also for some other well-known estrogen-regulated parameters, including uterine weight, thymus weight, and fat mass. Three-month-old ovariectomized (OVX) GPR30-deficient mice (GPR30(-/-)) and wild-type (WT) mice were treated with either vehicle or increasing doses of estradiol (E(2); 0, 30, 70, 160, or 830 ng.mouse(-1).day(-1)). Body composition [bone mineral density (BMD), fat mass, and lean mass] was analyzed by dual-energy-X ray absorptiometry, while the cortical and trabecular bone compartments were analyzed by peripheral quantitative computerized tomography. Quantitative histological analyses were performed in the distal femur growth plate. Bone marrow cellularity and distribution were analyzed using a fluorescence-activated cell sorter. The estrogenic responses on most of the investigated parameters, including increase in bone mass (total body BMD, spine BMD, trabecular BMD, and cortical bone thickness), increase in uterine weight, thymic atrophy, fat mass reduction, and increase in bone marrow cellularity, were similar for all of the investigated E(2) doses in WT and GPR30(-/-) mice. On the other hand, E(2) treatment reduced longitudinal bone growth, reflected by decreased femur length and distal femur growth plate height, in the WT mice but not in the GPR30(-/-) mice compared with vehicle-treated mice. These in vivo findings demonstrate that GPR30 is not required for normal estrogenic responses on several major well-known estrogen-regulated parameters. In contrast, GPR30 is required for a normal estrogenic response in the growth plate.

Estrogen Receptor-β Inhibits Skeletal Growth and Has the Capacity to Mediate Growth Plate Fusion in Female Mice†

To determine the long‐term role of ERβ in the regulation of longitudinal bone growth, appendicular and axial skeletal growth was followed and compared in female ERβ−/−, ERα−/−, and ERα−/−β−/− mice. Our results show that ERβ inhibits appendicular and axial skeletal growth and has the capacity to induce fusion of the growth plates.

Hormonal Regulation of Growth Plate Cartilage

Longitudinal bone growth occurs in the growth plate through a process called endochondral bone formation, a process where resting zone chondrocytes are recruited to start active proliferation and then undergo differentiation, followed by apoptosis and later mineralization. The balance between proliferation and differentiation is a crucial regulatory step controlled by various growth factors/hormones acting in both endocrine and paracrine/autocrine ways. From studies of individuals with aromatase deficiency and a boy with defective oestrogen receptor (ER)-alpha it has become clear that oestrogen action is indispensable for normal pubertal growth and growth plate fusion. Both oestrogen receptors, ER-alpha and ER-beta, are expressed in the growth plate in boys and girls throughout pubertal development. Any functional role of ER-beta has not yet been defined in the human growth plate. Increased understanding about the effects of oestrogen and the interactions between oestrogens and other endocrine factors within the growth plate is important for the development of new treatment strategies in different disorders affecting longitudinal bone growth. As new specific modulators of oestrogen receptors are developed, these could offer more specific ways to modulate longitudinal growth and growth plate fusion.

Growth failure in early life: An important manifestation of Turner syndrome

The goals of this study were to test the hypothesis that girls with Turner syndrome (TS) experience growth failure early in life and to establish model-based normative growth charts for 0- to 8-year-old American girls with TS. Full-term girls with TS who had 5 or more measurements of height obtained during their first 10 years of life prior to initiation of growth hormone, estrogen and/or androgen therapy were eligible for this study. A nonlinear mixed-effects model comprising the first two components of the infancy-childhood-puberty (ICP) model of growth was fitted to the longitudinal height measurements and compared with those of healthy American girls. Height measurements (n = 1,146) from 112 girls with TS (45,X: 57.1%; 45,X/46,XX: 12.5%; 46,X, iso(X): 4.5%, and other: 25.9%) were analyzed. Mean height SDS fell from –0.68 at birth to –1.60 at 1 year, –1.80 at 2 years and –1.95 at 3 years. When compared to controls (676 girls, 4,537 measurements), girls with TS grew more slowly due to three principal factors: a slow growth rate of the infancy component, a slow growth rate at the onset of the childhood component, and delayed onset of the childhood component. Traditional concepts of growth failure in TS should be revised. Physicians should consider the diagnosis of TS in any girl with unexplained failure to thrive or short stature, even in the first 3 years of life.

Additive Protective Effects of Estrogen and Androgen Treatment on Trabecular Bone in Ovariectomized Rats

Both ER and AR activation regulates trabecular bone mass. We show that combined estrogen and androgen treatment results in additive protection of trabecular bone in OVX rats. This may in part be attributable to the effect of AR activation to attenuate the inhibitory effect of ER activation on bone formation.