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Bone Abstracts (2017) 6 P017 | DOI: 10.1530/boneabs.6.P017

ICCBH2017 Poster Presentations (1) (209 abstracts)

Bone mineral density in children and adolescents with neurofibromatosis type I: mineralization during growth and pubertal development

Giulia Rodari 1 , Giulietta Scuvera 2 , Fabio M Ulivieri 3 , Francesca Menni 2 , Veronica Saletti 4 , Silvia Esposito 4 , Eriselda Profka 1 , Silvia Bergamaschi 1 , Cristina Eller Vainicher 1 , Maura Arosio 1 , Susanna Esposito 2, & Claudia Giavoli 1

1Endocrinology and Metabolic Diseases Unit, Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy; 2Pediatric Highly Intensive Care Unit, Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy; 3Bone Metabolic Unit, Division of Nuclear Medicine, Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, Milan, Italy; 4Developmental Neurology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy; 5Pediatric Clinic, Università degli Studi di Perugia, Perugia, Italy.

Objectives: The present study aims at evaluating bone mineral density (BMD) in a population of children with Neurofibromatosis type I (NF1), with particular focus on changes occurring during growth and pubertal development, trying to understand the magnitude and timing of onset of BMD impairment in this multisystemic and progressive disease, the latter poorly defined so far.

Methods: Bone metabolic markers (total calcium, phosphorus, bone alkaline phosphatase, parathyroid hormone, 25OH vitamin D, urinary calcium/creatinine ratio) and bone mineral status (by dual energy X-ray absorptiometry scans of the total body and lumbar spine with morphometric analysis) were assessed in fifty children (33 males; mean age ± S.D., 11.6±4 years). Bone mineral apparent density (BMAD) and trabecular bone score of the lumbar spine were also obtained.

Results: In our cohort areal BMD (aBMD) Z-score was below the mean in 88% of patients at lumbar spine (LS, 70% after correction for bone size) and in 86% considering total body (TB) scans. However, aBMD Z-score was <−2 in 14% (12% after correction for bone size) and 12% patients at LS and TB, respectively. Though BMD at all sites was higher in older and pubertal patients, LS aBMD Z-score (r=−0.54, P<0.0001), LS BMAD Z-score (r=−0.53, P<0.0001) and TB Z-score (r=−0.39, P=0.005) showed a negative correlation with growth and pubertal development (P=0.007, P=0.02, P=0.01, respectively), as suggesting that patients failed to gain as much as expected for age. Hypovitaminosis D was highly prevalent, as 98% patients had 25OHD concentrations below 30 ng/mL (75 nmol/L) and 18% less than 12 ng/ml (30 nmol/l). No statistically significant correlation between biochemical and densitometric data was found.

Conclusion: Bone mineral density impairment seems to become more evident with growth and pubertal development in NF1 patients, thus identifying childhood as the best timing frame to implement prevention strategies to allow a correct bone accrual and reduce future fractures risk. Trabecular bone score, providing information on bone quality even in the absence of age and gender adjusted normative data, could be useful during longitudinal follow-up for better characterizing bone impairment in these patients.

Disclosure: The authors declared no competing interests.

Volume 6

8th International Conference on Children's Bone Health


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