[Osteopenia in children with juvenile idiopathic arthritis].

UNLABELLED: The aim of the study was to evaluate the presence and etiopathogenesis of osteopenia in 41 children with Juvenile Idiopathic Arthritis (JIA).

METHODS

Bone status was evaluated by quantitative ultrasound using a Sunlight Omnisense 7000s Ultrasound Bone Sonometer. Measurements were performed at the distal radius and midshaft tibia. Results were obtained as Speed of sound (SOS) and Z-score. We used standardised clinical evaluation (modified Giannini's criteria, CHAQ). ESR, Fibrinogen, serum calcium, magnesium, alkaline phosphatase, protein electrophoresis, 25-OH vitamin D (RIA) and urinary Hydroxyproline were obtained in all patients. Osteopenia was present in 15 (36.5%) patients. Statistical analysis was performed with SPSS 13.0.

RESULTS

Age, sex, age at onset, disease duration, life standards and duration of corticotherapy and methotrexate treatment were not related to osteopenia in our study. The disease activity, evaluated by clinical criteria, ESR and Fibrinogen, was strongly associated with osteopenia (p<0.001). Nutritional status was an independent risk factor for osteopenia (p<0.001). Low serum calcium (p=0.034), magnesium (p=0.010), 25-OH vitamin D (p=0.091) and alkaline phosphatase (p=0.31) were more frequent in patients with osteopenia. Hydroxyproline was increased in all patients with osteopenia (p<0.001).

CONCLUSIONS

Osteopenia was a frequent (36.5%) complication of JIA in our study. The disease activity and nutritional status were the most important risk factors for osteopenia. The increase of bone reabsorption was the main pathogenic mechanism of osteopenia in our study. Calcium and magnesium deficits were related to osteopenia. Decrease of bone synthesis was not associated with osteopenia in the present study.