Bone mineralization in children and adolescents with type 1 diabetes

OBJECTIVE: to evaluate the occurrence of osteopenia and the prognostic factors of bone mass in a pediatric group with type 1 diabetes. METHODS: the following parameters were analyzed in a group of 23 patients with type 1 diabetes aged 10.9±2.9 years: bone mineral density, serum C peptide, glycosylated hemoglobin, serum calcium, serum alkaline phosphatase, serum phosphorus and calciuria. Clinical variables included age, weight, height, body mass index, pubertal stage, insulin doses, duration of diabetes and calcium intake. Bone mineral density was evaluated in the lumbar spine and the results were expressed in deviation standard score by age and sex. Calcium intake was calculated based on feeding report, body mass index was calculated using the "Quetelet" formula and pubertal stage was defined according to the Tanner - Whitehouse criteria. Simple linear regression was used to analyze correlations between variables and the Mann - Whitney U test was used to compare groups. RESULTS: average bone mineral density was normal (-0.75±1.01 SD). However we verified that 39.1% of the patients had osteopenia. When comparing data of osteopenic patients (n = 9) to non-osteopenic patients (n =1 4), we observed that C peptide of osteopenic group was higher than that of non-osteopenic group (0.56±0.18 versus 0.29±0.20; p < 0.05). Body mass index and C peptide correlated with bone mineral density. Duration of diabetes was inversely correlated with C peptide (p < 0.01) and directly correlated with insulin doses (p < 0.01). CONCLUSION: osteopenia occurred in 39.1% of the patients with type 1 diabetes. The presence of osteopenia was related to higher levels of C peptide.