Annemieke M. Boot

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 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.

Peak bone mineral density, lean body mass and fractures

BACKGROUND During childhood and adolescence, bone mass and lean body mass (LBM) increase till a plateau is reached. In this longitudinal and cross-sectional study, the age of reaching the plateau was evaluated for lumbar spine and total body bone mass measurements and lean body mass. The association between fractures and bone mineral density (BMD) was studied. PATIENTS AND METHODS We included 501 healthy participants, 141 males and 360 females, aged 13-29 years. Of these 90 had participated in a previous longitudinal study of 444 participants, aged 4-20 years (for the first measurement) and 198 participants, aged 8-25 years (for a second measurement). BMD and body composition were measured with dual energy X-ray absorptiometry (DXA). Volumetric BMD (bone mineral apparent density, BMAD) was calculated. All the data were used to determine the age of reaching the plateau. RESULTS The plateau for lumbar spine BMD, BMAD, total body BMD, bone mineral content and LBM was reached between 18 and 20 years of age in females and between 18 and 23 years in males. The prevalence of fractures was 37% in males and 28% in females. Total body BMD Z-score was significantly lower in all participants who had had a fracture (p<0.05), whereas lumbar spine BMD and BMAD was only significantly lower in females who had had fractures (p=0.007 and p<0.001, respectively). Mean lumbar spine BMAD Z-score at the previous measurement was significantly lower in the participants who had a first fracture between the last two measurements (p=0.04). CONCLUSION Peak BMD and peak LBM were attained between 18 and 20 years in females and between 18 and 23 years in males in this study using longitudinal and cross sectional data in the age range of 4 to 30 years. A significantly lower total body BMD was seen in participants who had had a fracture and a lower lumbar spine BMD and BMAD in females who had had a fracture. Lumbar spine BMAD Z-score seems to be a good predictor for future fractures.

Long-Term Effects of Growth Hormone Therapy on Bone Mineral Density, Body Composition, and Serum Lipid Levels in Growth Hormone Deficient Children: A 6-Year Follow-Up Study

Aim: To study the effects of growth hormone (GH) deficiency (GHD) and GH replacement therapy (GHRx) on bone mineral density (BMD) and body composition. Methods: 59 GHD children participated (age range 0.4–16.9 years); the follow-up period was 6 years. Lumbar spine BMD (BMD_LS), total-body BMD (BMD_TB), and body composition were measured prospectively using dual-energy X-ray absorptiometry. Results: Mean BMD_LSand BMD_TB were significantly reduced at the time of the diagnosis. The bone mineral apparent density of the lumbar spine (BMAD_LS) was reduced to a lesser degree. The BMAD_LS increased to normal values after 1 year; BMD_LS and BMD_TB normalized 1 year later. At the time of the diagnosis, the lean body mass was reduced and steadily increased during GHRx. Percentage of body fat was increased at baseline and normalized within 6 months. The severity of GHD was not associated with the BMD at diagnosis or the response to GHRx. Conclusion: Areal BMD_LS and BMD_TB and, to a lesser extent, BMAD_LS are decreased in GHD children, but normalize within 1–2 years.

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.

Successful Long-Term Growth Hormone Therapy in a Girl with Haploinsufficiency of the Insulin-Like Growth Factor-I Receptor due to a Terminal 15q26.2->qter Deletion Detected by Multiplex Ligation Probe Amplification

CONTEXT Microscopically visible heterozygous terminal 15q deletions encompassing the IGF1R gene are rare and usually associated with intrauterine growth retardation and short stature. The incidence of submicroscopic deletions is unknown, as is the effect of GH therapy in this condition. OBJECTIVE The objective of the study was to describe the use of a novel genetic technique [multiplex ligation probe amplification (MLPA)] to detect haploinsufficiency of the IGF1R gene in a patient suspected of an IGF1R gene defect and evaluate the effect of long-term GH therapy. PATIENT A 15-yr-old adolescent, born small for gestational age, showed persistent postnatal growth retardation, microcephaly, and elevated IGF-I levels. She had been treated with GH since the age of 5 yr. METHODS MLPA and array comparative genomic hybridization (aCGH) were performed to examine gene copy number changes. Dermal fibroblast cultures were used for functional analysis. RESULTS With MLPA, a deletion of one copy of the IGF1R gene was detected, defined by aCGH as a loss of 15q26.2->qter. IGF1R mRNA expression was decreased in fibroblasts. IGF-I binding and type 1 IGF receptor protein expression as well as activation of type 1 IGF receptor autophosphorylation and protein kinase B/Akt by IGF-I tended to be lower, but this did not reach statistical significance. GH treatment resulted in a good growth response and a normal adult height. CONCLUSIONS MLPA and aCGH are useful tools to detect submicroscopic deletions of the IGF1R gene in patients born small for gestational age with persistent growth failure. The phenotype resembles that of a heterozygous inactivating IGF1R mutation. Long-term GH therapy causes growth acceleration in childhood and a normal adult height.

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.

Epidemiology of low bone mineral density and fractures in children with severe cerebral palsy: a systematic review.

Aim  Children with severe cerebral palsy (CP) are at risk for developing low bone mineral density (BMD) and low‐impact fractures. The aim of this study was to provide a systematic literature review of the epidemiology of fractures and low BMD in children with severe CP, with an emphasis on risk factors. Gross Motor Function Classification System (GMFCS) levels IV and V were criteria for severe cerebral palsy.

Idiopathic infantile arterial calcification: clinical presentation, therapy and long-term follow-up

Idiopathic infantile arterial calcification (IIAC) is a rare disease characterised by extensive depositions of hydroxyapatite in the internal elastic lamina of medium-sized and large arteries, frequently accompanied by periarticular calcifications. We report on three patients with various presenting signs and symptoms. Diagnostic imaging techniques and therapy with bisphosphonates will be discussed. For the first time long-term follow-up of up to 25 years will be reported.

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.