Bone mineral density in diabetic children and adolescents: a follow-up study

To establish whether T1DM can affect bone mineral density (BMD) in children and adolescents.

We performed a cross-sectional and longitudinal study of 57 diabetic children and adolescents and 57 normal controls. Total body and lumbar BMD and bone mineral content (BMC) were assessed by DXA (Lunar DPX) and volumetric transformation was calculated using the Katzman formula for total body BMD (BMAD) and using the Kroger formula for Lumbar BMD (L2L4BMDvol). BMC, BMAD, BMDspine, and L2L4BMDvol were adjusted for confounding factors such as age, gender, BMI, height, weight, and pubertal stage.

BMDspine in the control group increased by 0.006 (g/cm(2))/year; while in the 39 diabetic patients longitudinally studied, it dropped by 0.006 (g/cm(2))/year during a follow-up period of 51 +/- 27 months. The average time spent weekly doing physical activity resulted in T1DM group directly correlated to BCM (P < 0.001) and inversely correlated with BMDspine (P < 0.05) and L2L4BMDvol (P < 0.01). L2L4BMDvol resulted significantly correlated with previous BMD spine (R = 0.63; P < 0.0001) and BMC evaluation (R = 0.42; P < 0.01) but not with BMAD. A second lumbar DXA evaluation performed in 38 patients after 1.00 +/- 0.16 years confirmed a small but significant decrease of 1.6% per year in L2L4BMDvol. The percentage of variation of L2L4BMDvol between the two evaluations was not correlated with the level of metabolic control, insulin requirement, and duration of the disease. Patients with complications showed similar L2L4BMDvol to patients without complications.

Diabetic children and adolescents show a slight negative pattern of spine mineralization, which does not depend on metabolic control and microvascular complications.