Background: Children with PNS may be at risk for metabolic bone disease because of biochemical derangement caused by the renal disease as well as steroid therapy. Few studied have been done for the evaluation of the magnitude of osteopenia in children with nephrotic syndrome but the results were conflicting.
Objectives: This study was conducted to highlight the prevalence as well as the contributing factors responsible for the development of osteopenia in children with primary nephortic syndrome (PNS).
Methods: Measurement of bone mineral density (BMD) in the lumbar spine region (L2-L4) using dual energy x-ray absorprometry (DEXA) was done in 42 patients with PNS (28 males and 14 females, aged 3 to 15 years) and 352 healthy age –and sex –matched Egyptian Children. Serum levels of osteocalcin, bone specific alkaline phosphatase (BAP), parathyroid hormone (PTH) and 25-OH cholecalciferol (25-HCC) and urinary dexoypyridinoline (Dpd) were measured in 14 patients out of the studied children and 12 healthy age-and sex-matched controls.
Results: Osteopenia was observed in 13 patients (30.9%), 7 of them had non-severe osteopenia (Z-score between -1 and -2.5) and 6 had severe osteopenia (Z-score more negative than -2.5). Compared to controls patients showed significantly lower 25-HCC [median = 17.5, range 11 -33.3, vs 66, range 61-69 ng/ml; p = 0.0001] and higher urinary Dpd [median = 81.1, range 76.5-174.9 vs 47.1, range 29.0-58.1 nmol/I; p = 0.001]. No significant differences were observed in serum osteocalcin, BAP and PTH between patients and controls. A significant negative correlation was observed between Z-score and the number of relapses (r = -0.35, p = 0.02). No correlation was observed between Z-score and total dose of corticosteroid, age or sex (p ˃ 0.05).
Conclusions: Osteopenia is evident in about one third of children with PNS. This osteopenia is associated with increased evidence of bone resorptive markers and normal osteoblastic markers and is related to the number of relapses. These patients may get benefits from vitamin D supplementation and bone anti-resorptive medications.