Bone mineral density in children with neurofibromatosis 1

Aim: Our aim was to detect the status of bone mineral density (BMD) in children with NF1, and thus to help the management of the skeletal complications of NF1. Methods: Dual-energy X-ray absorptiometry (DEXA) was performed in lumbar spine, total body, proximal femur and forearm in 31 children (3.1-18 years) with NF1. Correlations among the BMD values of four regions were calculated statistically. Z-scores of lumbar- and total body-BMD were also evaluated in 24 patients at and older than 5 years. Results: Eleven children had skeletal findings, including mild scoliosis in 5 patients. No case with total body-Z score <=-2 was detected. Lumbar-Z score was lower than -2 in 3 out of 24 cases. Patients with any skeletal involvement of NF1 were likely to have a lumbar-BMD lower than -2 in comparison with patients with no skeletal finding (odds ratio 4; 95% CI 0.01-4.62). Proximal femur-BMD values (g/cm(2)), yet forearm-BMDs, were correlated with both lumbar- and total body-BMD, regardless of skeletal involvements of NF1. Conclusions: Our findings suggest that lumbar- or proximal femur-DEXA, rather than forearm- or total body-DEXA, could reveal significantly decreased BMD in children with NF1, especially in those with skeletal involvement of NF1.