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.

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 (PO₄) using autoanalyzer. Bone quality assessed using dual energy X‐ray absorptiometry (DEXA).

Results: Diabetic patients showed significant increase in PO₄ 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.