Mervi K Mäyränpää, Inari S Tamminen, Heikki Kröger, Outi Mäkitie
In children the diagnosis of osteoporosis is based on fracture history and DXA-derived BMD. Bone biopsy is an invasive but accurate method to study bone characteristics. In this study we evaluated bone biopsy findings and their correlation with non-invasive measures of bone health. Transiliac bone biopsy was performed on 24 consecutive children (17 boys, median age 12 years, range 6-16 years) evaluated for suspected primary osteoporosis. Biopsy findings were compared with normative data and correlated with clinical, radiological, biochemical, and densitometric findings. The patients had sustained altogether 64 non-vertebral fractures (median 2.5) from low- or moderate-energy traumas, and 14 patients (58%) had vertebral fractures. The median lumbar spine BMD Z-score was –1.2 (range -3.1 to +1.0). Hypovitaminosis D was present in 58%. Histomorphometry showed low bone volume in 7 patients and normal bone volume in 17. Bone turnover was high in 7, low in 7, and normal in 10 patients. Histomorphometric findings correlated poorly with fracture history, serum bone turnover markers and DXA findings. Vitamin D deficiency and low lumbar BMD were associated with high bone turnover in the biopsy. These findings underscore the difficulties in diagnosing pediatric osteoporosis. Bone histomorphometry gives additional information and may be useful when considering bisphosphonate treatment in children with suspected primary osteoporosis.