Pediatric Diabetes 2011: 12: 536 – 546 doi: 10.1111/j.1399-5448.2010.00739.x All rights reserved © 2011 John Wiley & Sons A/S Pediatric Diabetes Original Article Parathormone – 25(OH)-vitamin D axis and bone status in children and adolescents with type 1 diabetes mellitus Hamed EA, Abu Faddan NH, Adb Elhafeez HA, Sayed D. Parathormone – 25(OH)-vitamin D axis and bone status in children and adolescents with type 1 diabetes mellitus. Pediatric Diabetes 2011: 12: 536 – 546. Background: Skeletal involvement in patients with type 1 diabetes mellitus (T1DM) has complex pathogenesis and despite numerous researches on this problem, many questions remain unanswered. Objective: This study aimed to assess bone status by measurement parathormone (PTH), 25-hydroxy vitamin D [25(OH)D] serum levels in children and adolescents with T1DM and its relation to insulin-like growth factor-1 (IGF-1), disease duration, puberty stage, and metabolic control. Patients and methods: This study included 36 children and adolescents with T1DM and 15 apparently healthy controls. Serum levels of 25(OH)D, PTH, IGF-1 measured using enzyme-linked immunosorbent assay (ELISA), while glycosylated hemoglobin (HbA1c), calcium (Ca), inorganic phosphorus (PO 4 ) using autoanalyzer. Bone quality assessed using dual energy X-ray absorptiometry (DEXA). Results: Diabetic patients showed significant increase in PO 4 and PTH levels, while significant decrease in Ca, IGF-1, and 25(OH)D serum levels. As much as 52.8% of patients showed reduced 25(OH)D, and 30.65% showed elevated PTH serum levels. In diabetic patients, abnormal bone status (osteopenia-osteoporosis) found mostly in total body (94.40%) then lumber-spine (88.90%), ribs (88.90%), pelvis (86.10%), thoracic-spine (80.60%), arms (80.60%) and legs (77.80%), while head bones showed no abnormalities. Long diabetic duration had negative; meanwhile PTH, onset age, and puberty age had positive impact on bone status. Conclusions: Children and adolescent with T1DM have abnormal bone status mostly in axial skeleton which may be contributed to impairment of formation of 25(OH)D and IGF-1. Physical activity, calcium and vitamin D supplement seem important in T1DM. Elevated serum PTH level in diabetic patients is not uncommon and its positive correlation with bone status needs further investigations. Enas A Hamed a , Nagla H Abu Faddan b , Hebh A Adb Elhafeez c and Douaa Sayed d a Department of Physiology, Faculty of Medicine, Assiut University, Assiut, P. O. Box 71526, Egypt; b Department of Pediatrics, Pediatric Assiut University Hospital, Assiut, P. O. Box 71526, Egypt; c Department of Clinical Pathology, Assiut University Hospital, Assiut, P. O. Box 71526, Egypt; and d Department of Clinical Pathology, South Egypt Cancer Institute, Assiut University, Assiut, P. O. Box 71526, Egypt Key words: bone status – 25(OH)D – IGF-1 – PTH – TIDM Corresponding author: Assist. Prof. Enas A Hamed, MD, Department of Physiology, Faculty of Medicine, Assiut University, Assiut, P. O. Box 71526, Egypt. Tel: +2 0164743592; fax: +2 088 2333327; e-mail: eah3a2010@yahoo.com Submitted 22 July 2010. Accepted for publication 6 October 2010 The prevalence of type 1 diabetes mellitus (T1DM) in childhood is increasing with a worldwide annual increase estimated at 3% (range 2–5%) (1). T1DM has negative effects on bone health and leads to an increase in fracture risk among middle aged and older individuals (2). However, there is still some debate about the effect of diabetes on bone status during childhood and adolescence (3, 4). Moreover, there is no general agreement on the relative importance of several diabetes – specific characteristics, such as age of onset, diabetic duration, glycemic control, and insulin regimen on bone health (5). Puberty has a key role in bone development. Skeletal mass approximately doubles at the end of adolescence (6). The pubertal phase is characteristically associated with a reduction in insulin sensitivity, which is known to be more severe in patients with T1DM, and might negatively influence growth and height gain (7). Identifying risk factors that predispose to a low bone mineral density (BMD) in diabetic patients is therefore desirable. 536