Abstract
Aim: To investigate the relationship of forearm length (FL) or height to bone parameters of the forearm of a normal pediatric population in comparison to individuals with osteogenesis imperfecta (OI). Methods: Data on FL, height and peripheral quantitative computed tomography measurements of the forearm were collected from participants of the DONALD study (140 males and 156 females; age 5–19 years) and from 73 patients with OI (53 males; mean age ± SD: 11.7 ± 3.3 years). Bone mineral content (BMC) was transformed into standard deviation score (SDS) according to height or FL. Results: Height and Tanner stages significantly predicted FL in males (R2adjusted = 0.960) and females (R2adjusted = 0.934). Height was a stronger predictor of FL than Tanner stages. Compared to controls, patients with OI were characterized by lower BMC-SDSFL and lower BMC-SDSheight (–0.37 ± 1.77 vs. 0.00 ± 0.97, p = 0.002, and –0.15 ± 5.0 vs. –0.02 ± 1.01, p = 0.011, respectively). BMC-SDSFL was not significantly lower than BMC-SDSheight in controls, and also not lower in patients with OI (p = 0.865 and p = 0.809). The height/FL ratio was significantly decreased in patients with OI (mean ± SD: 6.34 ± 0.38 vs. 6.45 ± 0.21, p = 0.001) compared with controls. Conclusion: Because of disproportional growth, BMC may be overestimated in OI patients.