Lumbar Bone Mineral Density at Final Height and Prevalence of Fractures in Treated Children with GH Deficiency

Lumbar bone mineral density (BMD) by dual energy x-ray absorptiometry was assessed in 46 (29 boys, 17 girls) treated patients with growth hormone deficiency (GHD) at final height, comparing the BMD results with normative data. Prevalence of fractures in patients during treatment and healthy controls (n = 100) during the corresponding time period was assessed. Lumbar BMD values at final height of fractured and fracture-free patients were compared between them. Lumbar BMD corrected for bone area was significantly (P < 0.01) reduced (boys, -0.4 +/- 0.8 Z score; girls, -0.5 +/- 0.7 Z score), but lumbar BMD corrected for bone size (BMDvolume) did not differ [P = not significant (NS); boys -0.2 +/- 1.0 Z score; girls, -0.3 +/- 1.0 Z score] from normal mean. Approximately 22% of patients had reduced lumbar BMD (Z score, -1 to -2). The fact that patients had a complete or partial GHD did not influence lumbar BMD. The prevalence of fractured patients did not differ (P = NS) from that of controls [n = 7 (15.2%) and n = 24 (24.0%), respectively; odds ratio, 1.837]. Lumbar BMDvolume of fractured patients was significantly (P < 0.02) lower than that of fracture-free (n = 39) patients (boys, 0.310 +/- 0.005 and 0.351 +/- 0.032 g/cm(3), respectively; girls, 0.326 +/- 0.027 and 0.382 +/- 0.036 g/cm(3), respectively). The percentage of the fractured patients with lumbar BMDvolume less than 1 SD of normal mean was significantly (P < 0.0001) higher than that of fracture-free patients [n = 6 (85.7%) and n = 4 (10.3%), respectively; odds ratio, 26.092). The fractured patients also showed reduced lumbar BMD corrected for bone area and BMDvolume at the time of fractures (-1.6 +/- 0.4 and -1.5 +/- 0.2 Z score, respectively). The results show that treated patients with GHD have normal mean values of lumbar BMDvolume at final height, but some patients have reduced lumbar BMD (Z score <1) with an increased susceptibility to fractures.