Disease Manifestations and Complications in Dutch X-Linked Hypophosphatemia Patients

X-linked hypophosphatemia (XLH) is the most common monogenetic cause of chronic hypophosphatemia, characterized by rickets and osteomalacia. Disease manifestations and treatment of XLH patients in the Netherlands are currently unknown. Characteristics of XLH patients participating in the Dutch observational registry for genetic hypophosphatemia and acquired renal phosphate wasting were analyzed. Eighty XLH patients, including 29 children, were included. Genetic testing, performed in 78.8% of patients, showed a PHEX mutation in 96.8%. Median (range) Z-score for height was - 2.5 (- 5.5; 1.0) in adults and - 1.4 (- 3.7; 1.0) in children. Many patients were overweight or obese: 64.3% of adults and 37.0% of children. All children received XLH-related medication e.g., active vitamin D, phosphate supplementation or burosumab, while 8 adults used no medication. Lower age at start of XLH-related treatment was associated with higher height at inclusion. Hearing loss was reported in 6.9% of children and 31.4% of adults. Knee deformities were observed in 75.0% of all patients and osteoarthritis in 51.0% of adult patients. Nephrocalcinosis was observed in 62.1% of children and 33.3% of adults. Earlier start of XLH-related treatment was associated with higher risk of nephrocalcinosis and detection at younger age. Hyperparathyroidism longer than six months was reported in 37.9% of children and 35.3% of adults. This nationwide study confirms the high prevalence of adiposity, hearing loss, bone deformities, osteoarthritis, nephrocalcinosis and hyperparathyroidism in Dutch XLH patients. Early start of XLH-related treatment appears to be beneficial for longitudinal growth but may increase development of nephrocalcinosis.

Body mass index at diagnosis of a childhood brain tumor; a reflection of hypothalamic-pituitary dysfunction or lifestyle?

PURPOSE

Childhood brain tumor survivors (CBTS) are at risk of becoming overweight, which has been shown to be associated with hypothalamic-pituitary (HP) dysfunction during follow-up. Body mass index (BMI) at diagnosis is related to BMI at follow-up. It is uncertain, however, whether aberrant BMI at brain tumor diagnosis reflects early hypothalamic dysfunction or rather reflects genetic and sociodemographic characteristics. We aimed to examine whether BMI at childhood brain tumor diagnosis is associated with HP dysfunction at diagnosis or its development during follow-up.

METHODS

The association of BMI at diagnosis of a childhood brain tumor to HP dysfunction at diagnosis or during follow-up was examined in a Dutch cohort of 685 CBTS, excluding children with craniopharyngioma or a pituitary tumor. Individual patient data were retrospectively extracted from patient charts.

RESULTS

Of 685 CTBS, 4.7% were underweight, 14.2% were overweight, and 3.8% were obese at diagnosis. Being overweight or obese at diagnosis was not associated with anterior pituitary deficiency or diabetes insipidus at diagnosis or during follow-up. In children with suprasellar tumors, being obese at diagnosis was associated with central precocious puberty.

CONCLUSION

Overweight or obesity at diagnosis of a childhood brain tumor seems not to be associated with pituitary deficiencies. These results suggest that genetics and lifestyle may be more important etiologic factors for higher BMI at diagnosis in these children than hypothalamic dysfunction. To improve the long-term outcome of CBTS with regards to overweight and obesity, more attention should be given to lifestyle already at the time of brain tumor treatment.

Prevalence and risk factors of hypothalamic-pituitary dysfunction in infant and toddler childhood brain tumor survivors

OBJECTIVE

Childhood brain tumor survivors (CBTS) are at risk to develop hypothalamic-pituitary (HP) dysfunction (HPD). The risk for HPD may vary between different age groups due to maturation of the brain and differences in oncologic treatment protocols. Specific studies on HPD in infant brain tumor survivors (infant-BTS, 0-1 years at diagnosis) or toddler brain tumor survivors (toddler-BTS, ≥1-3 years) have not been performed.

PATIENTS AND METHODS

A retrospective nationwide cohort study in CBTS was performed. Prevalence and risk factors for HPD were compared between infant-, toddler-, and older-BTS. Subgroup analysis was performed for all non-irradiated CBTS (n = 460).

RESULTS

In total, 718 CBTS were included, with a median follow-up time of 7.9 years. Overall, despite the less frequent use of radiotherapy (RT) in infants, no differences in the prevalence of HPD were found between the three groups. RT (OR: 16.44; 95% CI: 8.93-30.27), suprasellar tumor location (OR: 44.76; 95% CI: 19.00-105.49), and younger age (OR: 1.11; 95% CI: 1.05-1.18) were associated with HP dysfunction. Infant-BTS and toddler-BTS showed more weight gain (P < 0.0001) and smaller height SDS (P = 0.001) during follow-up. In non-irradiated CBTS, infant-BTS and toddler-BTS were significantly more frequently diagnosed with TSH-, ACTH-, and ADH deficiency, compared to older-BTS.

CONCLUSION

Infant and toddler brain tumor survivors seem to be more vulnerable to develop HP dysfunction than older children. These results emphasize the importance of special infant and toddler brain tumor treatment protocols and the need for endocrine surveillance in children treated for a brain tumor at a young age.

Management and consequences of postoperative fluctuations in plasma sodium concentration after pediatric brain tumor surgery in the sellar region: a national cohort analysis

PURPOSE

Severe fluctuations in plasma sodium concentration and plasma osmolarity, including central diabetes insipidus (CDI), may have significant influence on postoperative morbidity and mortality after pediatric brain tumor surgery.The aim of this study was to describe the frequency, severity and neurological consequences of these fluctuations in pediatric brain tumor survivors.

METHODS

A retrospective, multi-institutional chart review was conducted among all children who underwent brain tumor surgery in the sellar or suprasellar region in seven university hospitals in the Netherlands between January 2004 and December 2013.

RESULTS

Postoperative CDI was observed in 67.5% of 120 included children. Fluctuations of plasma sodium concentration ≥ 10 mmol/L/24 h during the first ten postoperative days were seen in 75.3% of patients with CDI, with a maximum delta of 46 mmol/L/24 h. When compared to patients without CDI, altered mental status occurred more frequently in patients with postoperative CDI (5.1 vs. 23.5% respectively, p = 0.009). Low plasma sodium concentration was related to altered mental status and the occurrence of seizures. Frequency and severity of fluctuations in plasma sodium concentration during the first ten postoperative days were significantly higher in patients with permanent CDI at last follow-up than in patients with transient CDI or without CDI (p = 0.007).

CONCLUSION

Postoperative CDI is a common complication after pediatric brain tumor surgery in the sellar or suprasellar region. Extreme plasma sodium concentrations and large intra-day fluctuations still occur and seem to influence the postoperative neurological course. These results illustrate the need for intensive monitoring in a highly experienced center.

Bone mineral density after childhood cancer in 346 long-term adult survivors of childhood cancer

SUMMARY

More than 45 % of long-term childhood cancer survivors (CCS) were diagnosed with osteopenia. Our data suggest that greater awareness for osteopenia is warranted in long-term CCS, especially in survivors who are older than 30 years, male, and underweight and were treated with cranial-spinal radiotherapy and/or steroids.

INTRODUCTION

Osteopenia is a potential complication of childhood cancer treatment, but the magnitude of this problem in survivors is unknown. We examined (determinants of) bone mineral density (BMD) status in long-term survivors of adult childhood cancer.

METHODS

This retrospective single-centre cohort study included 346 subjects with the most common types of childhood cancer. Subjects had a median age at diagnosis of 7.0 years (range 0.1-16.8 years), a median age at follow-up of 24.5 years (range 18.0-47.6 years) and a median follow-up time of 16.7 years (range 5.6-39.9 years). Total body BMD (BMDTB) and BMD of the lumbar spine (BMDLS) were measured by dual X-ray absorptiometry. Osteopenia was defined as BMD standardized deviation score (SDS) below -1.

RESULTS

Survivors had a lower BMDTB and BMDLS (mean SDS -0.55; p<0.001 and -0.30; p<0.001, respectively) as compared to healthy peers. Osteopenia (BMDTB and/or BMDLS) was present in 45% of the survivors. Multivariate logistic regression analyses identified age at diagnosis<12 years, age>30 years at follow-up, male gender, underweight at follow-up and treatment with cranial-spinal radiotherapy or prednisone as independent prognostic factors for osteopenia.

CONCLUSIONS

This large cohort of childhood cancer survivors identified osteopenia in 45% of CCS. This indicates that greater awareness is warranted, especially in survivors who are older than 30 years, male, have underweight and were treated with cranial-spinal radiotherapy and/or steroids.

A rare cause of facial nerve palsy in children: hyperostosis corticalis generalisata (Van Buchem disease). Three new pediatric cases and a literature review

Differential diagnosis of facial nerve palsy in children is extensive. We report on three pediatric cases presenting with facial nerve palsy caused by hyperostosis corticalis generalisata (Van Buchem disease). This autosomal recessive disease is characterized by progressive bone overgrowth, with narrowing of the neuroforamina in the skull causing cranial neuropathies. These three new cases of Van Buchem disease are of interest because of exceptionally early presentation of symptoms. Furthermore, this is the first report describing bilateral papilledema in a child with Van Buchem disease. Head computerized tomography (CT) scan revealed thickened calvarium, skull base and mandible in all three children, with narrowed facial nerve canals. Bone mineral density (BMD) was markedly increased at all measured points and biochemical markers of bone formation were significantly elevated. Diagnosis of Van Buchem disease was genetically confirmed. The cases are unique in that these are the first well-documented pediatric cases of Van Buchem disease.

Fertility of tall girls treated with high-dose estrogen, a dose-response relationship

CONTEXT

High-dose estrogen treatment to reduce final height of tall girls increases their risk for infertility in later life.

OBJECTIVE

The aim was to study the effect of estrogen dose on fertility outcome of these women.

DESIGN/SETTING

We conducted a retrospective cohort study of university hospital patients.

PATIENTS

We studied 125 tall women aged 20-42 yr, of whom 52 women had been treated with 100 μg and 43 with 200 μg of ethinyl estradiol (EE) in adolescence.

MAIN OUTCOMES

Time to first pregnancy, treatment for infertility, and live birth rate were measured.

RESULTS

The time to first pregnancy was increased in treated women. Of untreated women, 80% conceived within 1 yr vs. 69% of women treated with 100 μg EE and 59% of women treated with 200 μg EE. This trend of increased time to pregnancy with increasing estrogen dose was significant (log rank trend test, P = 0.01). Compared with untreated women, fecundability was reduced in women treated with both 100 μg EE [hazard ratio = 0.42; 95% confidence interval (CI), 0.19-0.95] and 200 μg EE (hazard ratio = 0.30; 95% CI, 0.13-0.72). We also observed a significant trend in the incidence of treatment for infertility with increased estrogen dose (P = 0.04). Fecundity was affected in women treated with 200 μg EE who had reduced odds of achieving at least one live birth (odds ratio = 0.13; 95% CI, 0.02-0.81), but not in women treated with 100 μg EE.

CONCLUSIONS

We report a dose-response relationship between fertility in later life and estrogen dose used for the treatment of tall stature in adolescent girls; a higher estrogen dose is associated with increased infertility.

Genetic variation in candidate genes like the HMGA2 gene in the extremely tall

BACKGROUND/AIMS

Genetic variation in several candidate genes has been associated with short stature. Recently, a high-mobility group A2 (HMGA2) gene SNP has been robustly associated with height in the general population. Only few have attempted to study these genes in extremely tall stature. We therefore studied common genetic variation in candidate genes for height in extremely tall Dutch.

METHODS

We included 116 constitutionally tall cases with height >2 SD and 103 controls with normally distributed height <2 SD. We genotyped 10 common polymorphisms previously associated with height variation.

RESULTS

The HMGA2 gene SNP was significantly associated with tall stature. Using a logistic regression model, we calculated that carrying the HMGA2 (rs1042725) C allele significantly increased the odds of being tall (OR = 1.53, 95% CI 1.02-2.28; p = 0.03). In addition, controls with one or two copies of the C allele were significantly taller than controls carrying the TT genotype [TC: mean (SD) +0.61 (0.21) SDS; p = 0.004, and CC: +0.77 (0.25) SDS; p = 0.003].

CONCLUSION

Our study shows that a common polymorphism in the HMGA2 gene is not only associated with height variation in the general population but also plays an important role in one of the extremes of the height distribution.

Common polymorphisms in the GH/IGF-1 axis contribute to growth in extremely tall subjects

CONTEXT/OBJECTIVE

The growth hormone (GH)/insulin-like growth factor-1(IGF-1) axis is the key regulator of somatic growth in humans and its genes are plausible candidates to study the genetics of height variation. Here, we studied polymorphic variation in the GH/IGF-1 axis in the extremely tall Dutch.

METHODS

Case-control study of 166 tall cases with height >2 SDS and 206 controls with normally distributed height <2 SDS. Excluded were subjects with endocrine disorders or growth syndromes. We analyzed genomic DNA at 7 common polymorphisms in the GH-1, GH receptor (GHR), IGF-1 and IGFBP-3 genes.

RESULTS

The association of the GH-1 1663 SNP with tall stature approached statistical significance, with the T-allele more present in the tall (allele frequency (AF): 0.44 vs. 0.36; p=0.084). Moreover, haplotype frequencies at this locus were significantly different between cases and controls, with the GGT haplotype most commonly seen in cases (p=0.01). Allele frequencies of GHR polymorphisms were not different. For the IGF-1 CA-repeat we observed a higher frequency of homozygous 192-bp carriers among tall males compared to control males (AF: 0.62 vs. 0.55; p=0.02). The IGFBP-3 -202 C-allele occurred more frequently in cases than in controls (AF: 0.58 vs. 0.50; p=0.002). Within cases, those carrying one or two copies of the -202 C-allele were significantly taller than AA genotype carriers (AC, p=0.028 and CC, p=0.009). Serum IGFBP-3 levels were highest in AA genotype carriers, the -202 SNP explained 5.8% of the variation.

CONCLUSION

Polymorphic variation in the GH-1, IGF-1 and IGFBP-3 genes is associated with extremely tall stature. In particular, the IGFBP-3 -202 SNP is associated not only with being very tall but also with height variation within the tall.

Fertility and ovarian function in high-dose estrogen-treated tall women

BACKGROUND/OBJECTIVE

High-dose estrogen treatment to reduce final height of tall girls has been shown to interfere with fertility. Ovarian function has not been studied. We therefore evaluated fertility and ovarian function in tall women who did or did not receive such treatment in adolescence.

METHODS

This was a retrospective cohort study of 413 tall women aged 23-48 yr, of whom 239 women had been treated. A separate group of 126 fertile, normoovulatory volunteers aged 22-47 yr served as controls.

RESULTS

Fertility was assessed in 285 tall women (157 treated, 128 untreated) who had attempted to conceive. After adjustment for age, treated women were at increased risk of experiencing subfertility [odds ratio (OR) 2.29, 95% confidence interval (CI) 1.38-3.81] and receiving infertility treatments (OR 3.44, 95% CI 1.76-6.73). Moreover, fecundity was notably affected because treated women had significantly reduced odds of achieving at least one live birth (OR 0.26, 95% CI 0.13-0.52). Remarkably, duration of treatment was correlated with time to pregnancy (r = 0.23, P = 0.008). Ovarian function was assessed in 174 tall women (119 treated, 55 untreated). Thirty-nine women (23%) exhibited a hypergonadotropic profile. After adjusting for age category, treated women had significantly higher odds of being diagnosed with imminent ovarian failure (OR 2.83, 95% CI 1.04-7.68). Serum FSH levels in these women were significantly increased, whereas antral follicle counts and serum anti-Müllerian hormone levels were decreased.

CONCLUSION

High-dose estrogen-treated tall women are at risk of subfertility in later life. Their fecundity is significantly reduced. Treated women exhibit signs of accelerated ovarian aging with concomitant follicle pool depletion, which may be the basis of the observed subfertility.

Fatherhood in tall men treated with high-dose sex steroids during adolescence

BACKGROUND/OBJECTIVE

Sex steroid treatment to reduce final height of tall boys has been available since the 1950s. In women, it has been shown to interfere with fertility. In men, no such data are available. We therefore evaluated fertility and gonadal function in tall men who did or did not receive high-dose androgen treatment in adolescence.

METHODS

We conducted a retrospective cohort study of 116 tall men, of whom 60 had been treated. Reproductive and gonadal function was assessed by standardized interview, semen analysis, endocrine parameters, ultrasound imaging, and fatherhood. Mean age at treatment commencement was 14.2 yr, and mean follow-up was 21.2 yr.

RESULTS

Sixty-six men (36 treated and 30 untreated) had attempted to achieve fatherhood. The probability of conceiving their first pregnancy within 1 yr was similar in treated and untreated men (26 vs. 24; Breslow P=0.8). Eleven treated and 13 untreated men presented with a left-sided varicocele (P=0.5). Testicular volume, sperm quality, and serum LH, FSH, and inhibin B levels were comparable between treated and untreated men. However, treated men had significantly reduced serum T levels, adjusted for known confounders [mean (sd) 13.3 (1.8) vs. 15.2 (1.9) nmol/liter; P=0.005). In addition, testicular volume and serum inhibin B and FSH levels in treated men were significantly correlated with age at treatment commencement.

CONCLUSION

At a mean follow-up of 21 yr after high-dose androgen treatment, we conclude that fatherhood and semen quality in tall treated men are not affected. Serum testosterone levels, however, are reduced in androgen-treated men. Future research is required to determine whether declining testosterone levels may become clinically relevant for these men as they age.

Influence of birth size and body composition on bone mineral density in early adulthood: the PROGRAM study

BACKGROUND/OBJECTIVES

Low bone mineral density (BMD) may lead to osteoporosis and is associated with increased fracture risk. Associations between BMD and various factors have been reported. Our objective was to investigate whether birth size, lean body mass (LBM) and fat mass (FM) are determinants of BMD of the total body (BMD(TB)) and the lumbar spine (BMD(LS)).

METHODS

In the PROgramming factors for GRowth And Metabolism (PROGRAM) study of a cohort of 312 young adults aged 18-24 years, BMD(TB) and BMD(LS) were determined by dual-energy X-ray absorptiometry (DXA). Subsequently, differences in BMD(TB) and BMD(LS) were analysed in four subgroups: young adults born small for gestational age with short stature (SGA-S) or with catch-up growth (SGA-CU), or born appropriate for gestational age (AGA) with idiopathic short stature (ISS) or with normal stature (controls).

RESULTS

Adult weight, LBM, FM and weight gain during childhood were the main positive determinants for BMD(TB) in early adulthood, whereas birth size had no influence (adjusted R(2) = 0.50). Gender, adult weight, LBM, FM and weight gain were the significant determinants of BMD(LS). In the subgroups, after correction for age, gender and adult body size, the ISS group had a significantly lower BMD(TB) than controls but there was no difference in BMD(LS) between the subgroups.

CONCLUSIONS

Prenatal growth has no significant influence on BMD(TB) and BMD(LS) in early adulthood. Gender and postnatal growth, particularly weight gain, are the main positive determinants. To achieve a normal BMD in adulthood, healthcare workers should aim for a normal weight gain in children.

[Seizures in foreign newborns due to maternal vitamin-D deficiency]

In a Moroccan male, a Turkish female and a Sudanese male newborn who presented with seizures in the second week of life, hypocalcaemia was found. The hypocalcaemia was caused by neonatal vitamin-D deficiency as a result of maternal vitamin-D deficiency during pregnancy. The vitamin-D deficiency of the mothers was caused by the diminished exposure to sunlight as a result of wearing a veil and the dark pigmentation of the skin. The infants were cured by vitamin-D suppletion. With the increasing numbers of dark-skinned women and women who wear veils in the Dutch population, the group of pregnant women and newborns running a risk of vitamin-D deficiency is becoming larger. Therefore, the risk of hypocalcaemia and vitamin-D deficiency rickets in newborns is also increasing. In newborns with seizures, one should think of the possibility of neonatal vitamin-D deficiency, especially if the mothers belong to the group at risk.

Estrogen receptor alpha gene polymorphisms and bone mineral density in healthy children and young adults

The accretion of peak bone mass is largely under genetic control, and one of the potential candidate genes is the estrogen receptor alpha (ERalpha) gene. The association of ERalpha gene polymorphisms with bone mineral density (BMD) was investigated in a group of 147 healthy caucasian children, adolescents, and young adults (57 boys and 90 girls) in a cross-sectional and longitudinal study. The mean age was 11.3 years (4.3-19.9 years) at baseline and 15.6 years (7.6-25.3 years) at follow-up. Lumbar spine, total body BMD, and body composition were measured by dual energy X-ray absorptiometry and expressed as age- and sex-adjusted standard deviation scores (SDS). We analyzed two restriction fragment length polymorphisms, Pvull and Xbal, and haplotypes thereof. Subjects homozygous for haplotype 1 (px) (33% of the population) had 0.4 SD (standard deviation) lower lumbar spine BMD (P = 0.02) and bone mineral apparent density (BMAD) (P = 0.04) than those heterozygous or noncarriers for haplotype 1 (px) at baseline. Analysis of the follow-up data gave similar results. The association was stronger for the prepubertal than for the postpubertal subjects. Vertebral width SDS, total body BMD SDS, height SDS, body mass index SDS, lean body mass SDS, and percentage fat SDS did not significantly differ between the haplotypes. The age of menarche was not related to any of the haplotypes in girls. The present study shows that Pvull-Xbal ERalpha gene polymorphism is associated with BMD during childhood.

Digital radiogrammetry of the hand in a pediatric and adolescent Dutch Caucasian population: normative data and measurements in children with inflammatory bowel disease and juvenile chronic arthritis

We have evaluated the applicability of a new Digital X-ray Radiogrammetry (DXR) system in a Dutch Caucasian pediatric population. For this study we enrolled 535 healthy participants who all signed an informed consent form. In addition, 20 children suffering from inflammatory bowel disease (IBD) and juvenile chronic arthritis (JCA) were enrolled. Radiographs of the left hand were obtained from all participants. From the healthy population a subset of children with a history of forearm fractures were separately analyzed. Measurements consisted of DXR (X-posure; Pronosco-Sectra, Linköping, Sweden). Five hundred thirty-five subjects were enrolled in the study. Twenty-two subjects (4.3%) were discontinued (age 3-10 years), all because of a nonrecognizable radiograph by the DXR system. The short-term coefficient of variation of DXR in this population was 0.59%. Significant differences in DXR-BMD between boys and girls for the ages of 11, 12, 16, 17, and 18 years were found. There were also significant differences in DXR-BMD between the sequential Tanner stages. For 88 subjects repeat radiographs were available (mean interval 1.8 years). In all cases an increase in DXR-BMD was seen. Girls with IBD, JCA, or a history of forearm fractures and boys with IBD showed a significantly lower DXR-BMD compared with healthy controls. We show that DXR is an applicable technique in children. Also, in a small subpopulation it is possible to discriminate children with a high risk of low BMD.

Reference data for bone density and body composition measured with dual energy x ray absorptiometry in white children and young adults

AIMS

To obtain normative data on bone mineral density and body composition measured with dual energy x ray absorptiometry (DXA) from early childhood to young adulthood.

METHODS

Cross sectional results from 444 healthy white volunteers (4-20 years) in the Netherlands were combined with the results from 198 children who agreed to participate in the follow up study approximately four years later. DXA (Lunar, DPXL) of lumbar spine and total body was performed to assess bone density and body composition.

RESULTS

Bone density and lean body mass (LBM) increased with age. Maximal increase in bone density and LBM occurred around the age of 13 years in girls and approximately two years later in boys. Bone density of total body and lumbar spine showed an ongoing slight increase in the third decade. Mean fat percentage in boys remained at 10.5% throughout childhood, but increased in girls.

CONCLUSIONS

Most of the skeletal mass in lumbar spine and total body is reached before the end of the second decade, with a slight increase thereafter. This study provides reference values for bone density and body composition measured with DXA for children and young adults.

Bone density and body composition in chronic renal failure: effects of growth hormone treatment

Metabolic bone disease and growth retardation are common complications of chronic renal failure (CRF). We evaluated bone mineral density (BMD), bone metabolism, body composition and growth in children with CRF, and the effect of growth hormone treatment (GHRx) on these variables. Thirty-three prepubertal patients with CRF were enrolled including 18 children with growth retardation, who were treated with growth hormone for 2 years. Every 6 months, BMD of lumbar spine and total body, and body composition were measured by dual-energy X-ray absorptiometry. Biochemical parameters of bone turnover were assessed. Mean BMD of children with CRF did not differ from normal. During GHRx, BMD and bone mineral apparent density of lumbar spine and height SDS increased, whereas BMD of total body did not change. Lean body mass increased in the GH group. Alkaline phosphatase increased significantly in the GH group only. The other biochemical parameters of bone turnover increased in both groups, none of them correlated with the changes in BMD. No serious adverse effects of GHRx were reported. In conclusion, BMD of children with CRF did not differ from healthy children. Adequate treatment with alpha-calcidiol or the short duration of renal failure may have attributed to the absence of osteopenia in our patients. BMD of the axial skeleton and growth improved with GHRx.

Bone mineral density in children with acute lymphoblastic leukaemia

Bone mineral density (BMD) may be negatively affected by the disease or its treatment in patients with acute lymphoblastic leukaemia (ALL). Therefore, we evaluated lumbar spine and total body BMD and bone metabolism in children with ALL at diagnosis, during treatment with chemotherapy and 1 year after completion of treatment. 32 children (21 boys and 11 girls) participated in the study. 14 children started the study at diagnosis and 18 during or after the treatment period. Lumbar spine and total body BMD were measured with dual energy X-ray absorptiometry, and expressed as standard deviation scores (SDS). Blood samples were obtained to assess bone metabolism. 3 of 14 children had low lumbar spine BMD (< -2 S.D.) at diagnosis. All children had normal total body BMD. Markers of bone turnover were depressed. Total body BMD SDS decreased significantly during the first year of treatment (P < 0.001). Lumbar spine BMD SDS did not change significantly. Parameters of bone turnover increased to normal during the treatment period. Parathyroid hormone had increased significantly after 1 year (P < 0.05). Mineral homeostasis was disturbed in some patients during treatment. 4 of 9 patients had low total body BMD and 1 patient low lumbar spine BMD one year after completion of treatment. All patients had normal biochemical results at that time. In conclusion, lumbar spine BMD and bone turnover were decreased in some patients at diagnosis. Total body BMD decreased significantly during treatment and was low in 4 of the 9 patients 1 year after completion of the treatment.

Bone mineral density, bone metabolism and body composition of children with chronic renal failure, with and without growth hormone treatment

OBJECTIVE

Osteopenia has been reported in adult patients with chronic renal failure (CRF). Only a few studies have been performed in children. The objective of this study was to evaluate bone mineral density (BMD), bone turnover, body composition in children with CRF and to study the effect of GH on these variables.

DESIGN

Two groups were identified: patients with growth retardation who received GH (GH-group) and patients most of whom were not growth retarded who did not receive GH (no-GH-group). After an observation period of 6 months, the patients in the GH-group started GH treatment. Patients were studied every 6 months during 18 months.

PATIENTS

Thirty-six prepubertal patients (27 boys and 9 girls), mean age 7.9 years, with CRF participated in the study. The GH-group consisted of 17 patients of whom 14 completed one year treatment. The no-GH-group consisted of 19 patients, of whom 16 were followed for 6 months, 14 for 12 months and 13 for 18 months.

MEASUREMENTS

Lumbar spine BMD, total body BMD and body composition were assessed by dual energy X-ray absorptiometry, compared to age-and sex-matched reference values of the same population and expressed as standard deviation scores (SDS). BMD of appendicular bone was measured by quantitative microdensitometry (QMD). Blood samples were obtained to assess bone metabolism and growth factors.

RESULTS

Baseline mean lumbar spine and total body BMD SDS of all patients were not significantly different from normal. Mean lumbar spine and total body BMD SDS did not change significantly in the GH-group during GH treatment. The change of QMD at the midshaft during the first 6 months of GH treatment was significantly smaller than during the observation period (P < 0.01). Height SDS and biochemical markers of both bone formation and bone resorption increased significantly during GH treatment; 1,25-dihydroxyvitamin D remained stable. Lean tissue mass increased (P < 0.001) and percentage body fat decreased (P < 0.01) during GH treatment. BMD, the biochemical markers of bone turnover which are independent of renal function, and body composition remained stable in the no-GH-group.

CONCLUSIONS

Mean lumbar spine and total body BMD of children with chronic renal failure did not differ from healthy controls. The lack of a GH-induced increase in 1,25-dihydroxyvitamin D levels, probably due to treatment with alpha-calcidol, might be linked to the absence of a response in BMD during GH treatment in children with chronic renal failure.

Bone mineral density and nutritional status in children with chronic inflammatory bowel disease

BACKGROUND

Osteoporosis has been reported in adult patients with inflammatory bowel disease.

AIMS

To evaluate bone mineral density (BMD), nutritional status, and determinants of BMD in children with inflammatory bowel disease.

PATIENTS

Fifty five patients (34 boys and 21 girls, age range 4-18) were studied; 22 had Crohn's disease and 33 ulcerative colitis.

METHODS

Lumbar spine and total body BMD, and body composition were assessed by dual energy x ray absorptiometry (DXA). Results were expressed as standard deviation scores (SDS). Lean body mass was also assessed by bioelectrical impedance analysis (BIA). Yearly measurements during two years were performed in 21 patients.

RESULTS

The mean SDS of lumbar spine BMD and total body BMD were significantly lower than normal (-0.75 and -0.95, both p < 0.001). Height SDS and body mass index SDS were also decreased. The decrease in BMD SDS could not be explained by delay in bone maturation. The cumulative dose of prednisolone correlated negatively with lumbar spine BMD SDS (r = -0.32, p < 0.02). Body mass index SDS correlated positively with total body BMD SDS (r = 0.36, p < 0.02). Patients with Crohn's disease had significantly lower lumbar spine and total body BMD SDS than patients with ulcerative colitis, even after adjustment for cumulative dose of prednisolone. In the longitudinal data cumulative dose of prednisolone between the measurements correlated negatively with the change in lumbar spine and total body BMD SDS. Lean tissue mass measured by DXA had a strong correlation with lean body mass measured by BIA (r = 0.98).

CONCLUSIONS

Children with inflammatory bowel disease have a decreased BMD. Children with Crohn's disease have a higher risk of developing osteopaenia than children with ulcerative colitis. Corticosteroid therapy and nutritional status are important determinants of BMD in these patients.

Bone mineral density and body composition before and during treatment with gonadotropin-releasing hormone agonist in children with central precocious and early puberty

Major changes in bone mineral density (BMD) and body composition occur during puberty. In the present longitudinal study, we evaluated BMD and calculated volumetric BMD [bone mineral apparent density (BMAD)], bone metabolism, and body composition of children (32 girls and 2 boys) with central precocious and early puberty before and during treatment with GnRH agonist (GnRH). Patients were studied at baseline and during treatment for 6 months (n = 34), 1 yr (n = 33), and 2 yr (n = 16). Lumbar spine and total body BMD and body composition were measured with dual-energy x-ray absorptiometry. The variables were compared with age- and sex-matched reference values of the same population and expressed as SD score (SDS). Bone age was assessed. Serum calcium, phosphate, alkaline phosphatase, osteocalcin, the carboxyterminal propeptide of type I collagen (PICP), cross-linked telopeptide of collagen I (ICTP), 1,25 dihydroxyvitamin D and urinary hydroxyproline/creatinine, and calcium/ creatinine ratios were measured. Mean lumbar spine BMD SDS was significantly higher than zero at baseline (P < 0.02) and did not differ from normal, after 2 yr of treatment. Mean spinal BMAD SDS and total body BMD SDS were not significantly different from zero at baseline and had not changed significantly after 2 yr of treatment. During therapy, fat mass and percentage body fat SDS increased, whereas lean tissue mass SDS decreased. Mean lumbar spine BMD and BMAD and total body BMD SDS, calculated for bone age, were all lower than zero at baseline (BMD P < 0.001 and BMAD P < 0.05) and also after 2 yr treatment (respectively, P < 0.001, P < 0.05, and P < 0.01). Biochemical bone parameters were significantly higher than prepubertal values at baseline, and they decreased during treatment. In conclusion, patients with central precocious and early puberty had normal BMD for chronological age but low BMD for bone age, after 2 yr of treatment with GnRH. Bone turnover decreased during treatment. Changes in body composition resembled those seen in patients with GH deficiency.

Bone mineral density and bone metabolism of prepubertal children with asthma after long-term treatment with inhaled corticosteroids

Little is known about the effect of long-term treatment with inhaled corticosteroids (ICS) on bone mineral density (BMD) in asthmatic children. In the present cross-sectional study BMD, bone metabolism, height, body composition, and bone age were evaluated in 40 prepubertal children (21 boys) with asthma, treated with a moderate to high dose of ICS over a period of 3 to 8 years. Body composition and BMD of the lumbar spine and total body were measured by Dual Energy X-ray Absorptiometry. BMD results were compared with 148 prepubertal healthy children of the same population. Blood samples were taken for the determination of biochemical bone parameters. The asthmatic children had decreased height, lean tissue mass and fat mass, and a delay of bone maturation, indicating growth retardation. ICS-treated asthma was negatively correlated with total body BMD in a multiple regression model with adjustment for age, gender, height and weight (P = 0.01). Duration of ICS therapy correlated negatively with total body BMD when it was added to the model (P = 0.01). Lumbar spine BMD was not affected by ICS in children with ICS-treated asthma. If age of the asthmatic children was replaced by their bone age in the model, no significant correlation was found between ICS-treated asthma and total body or lumbar spine BMD. The biochemical parameters of bone metabolism were within normal limits. In conclusion, children with asthma who have used ICS daily for 3 to 8 years had lower total body BMD than healthy controls. Long-term longitudinal studies are needed to investigate whether these children attain a normal peak bone mass.

Changes in bone mineral density, body composition, and lipid metabolism during growth hormone (GH) treatment in children with GH deficiency

Adults with childhood onset GH deficiency (GHD) have reduced bone mass, increased fat mass, and disorders of lipid metabolism. The aim of the present study was to evaluate bone mineral density (BMD), bone metabolism, body composition, and lipid metabolism in GHD children before and during 2-3 yr of GH treatment (GHRx). Forty children with GHD, mean age 7.9 yr, participated in the study of bone metabolism and body composition; and an additional group of 17 GHD children, in the study of lipid metabolism. Lumbar spine BMD, total body BMD, and body composition were measured with dual-energy x-ray absorptiometry. Volumetric BMD (bone mineral apparent density, BMAD) was calculated to correct for bone size. BMD, BMAD, lean tissue mass, bone mineral content, fat mass, and percentage body fat were expressed as SD scores (SDS), in comparison with normative data of the same population. Lumbar spine BMD and BMAD and total body BMD were all decreased at baseline. All BMD variables increased significantly during GHRx, lumbar spine BMD SDS, already after 6 months of treatment. Lean tissue mass SDS increased continuously. Bone mineral content SDS started to increase after 6 months GHRx. Fat mass SDS decreased during the first 6 months of GHRx and remained stable thereafter. Biochemical parameters of bone formation and bone resorption did not differ from normal at baseline and increased during the first 6 months of GHRx. Serum 1,25 dihydroxyvitamin D increased continuously during GHRx, whereas PTH and serum calcium remained stable. Lipid profile was normal at baseline: Atherogenic index had decreased and apolipoprotein A1(Apo-A1) had increased after 3 yr of treatment. In conclusion, children with GHD have decreased bone mass. BMD, together with height and lean tissue mass, increased during GHRx. GHRx had a beneficial effect on lipid metabolism.

Determinants of body composition measured by dual-energy X-ray absorptiometry in Dutch children and adolescents

Knowledge about body composition is important in metabolic and nutritional studies. In this cross-sectional study the body composition of 403 healthy white Dutch children and adolescents was evaluated by using dual-energy X-ray absorptiometry (DXA). Possible determinants of body composition were analyzed. In 85 subjects the results of bioelectrical impedance analysis (BIA) were compared with DXA. Fat mass, lean tissue mass, and bone mineral content were greater in older boys and girls. Percentage body fat was greater in older girls but not in boys and it was higher in girls than in boys at all ages. From the age of 14 y boys had higher lean tissue mass and bone mineral content than girls. Tanner stage had a significant relation with body composition in both sexes. Percentage body fat was lower in boys in stage 4 than in stage 3 and was higher in consecutive Tanner stages in girls. After adjustment for age, Tanner stage was significantly positively related to lean tissue mass and bone mineral content in boys and girls and to percentage body fat and fat mass in girls. The profession of the parents and the education of the father had a significant negative correlation with percentage body fat and fat mass in girls (P < 0.01). Physical activity was related to lean tissue mass (P = 0.001) but not to fat mass in boys after adjustment for age. A high correlation and a small difference was found between lean body mass by BIA and lean tissue mass by DXA. Body composition in healthy Dutch children and adolescents is related to age, sex, Tanner stage, socioeconomic status, and physical activity.

Bone mineral density in children and adolescents: relation to puberty, calcium intake, and physical activity

The association of height, weight, pubertal stage, calcium intake, and physical activity with bone mineral density (BMD) was evaluated in 500 children and adolescents (205 boys and 295 girls), aged 4-20 yr. The BMD (grams per cm2) of lumbar spine and total body was measured with dual energy x-ray absorptiometry. Lumbar spine volumetric BMD was calculated to correct for bone size. BMD and volumetric BMD increased with age. During puberty, the age-dependent increment was higher. After adjustment for age, the Tanner stage was significantly associated with all three BMD variables in girls and with spinal BMD in boys. In boys, positive correlations were found between BMD and both calcium intake and physical activity after adjustment for age. Stepwise regression analysis with weight, height, Tanner stage, calcium intake, and physical activity as determinants with adjustment for age resulted in a model with Tanner stage in girls and weight in boys for all three BMD variables. The major independent determinant of BMD was the Tanner stage in girls and weight in boys.

Renal transplantation and osteoporosis

A cross sectional study assessed the bone mineral density (BMD) of 20 young adult patients who received a renal transplantation in childhood. The BMD of the lumbar spine, mainly trabecular bone, and of the total body, mainly cortical bone, were measured and expressed as an SD score. Fourteen patients (70%) had a BMD SD score of the lumbar spine below -1, of whom six patients were below -2. Fifteen patients (75%) had a BMD SD score of the total body below -1, of whom seven patients were below -2, Both trabecular and cortical bone appeared to be involved in the osteopenic process. The cumulative dose of prednisone was inversely correlated to both lumbar spine and total body BMD SD score. In a multiple regression analysis the cumulative dose of prednisone appeared to be the only factor with a significant effect on BMD SD score. Most young adult patients who had received a renal transplantation in childhood had moderate to severe osteopenia. Corticosteroid treatment played a major part in the development of osteopenia in these patients.