Role of hemoglobin A1c, duration and puberty on bone mineral density in diabetic children

Background: The aim of the present was to determine bone mineral density (BMD) in type 1 diabetic children and the roles of hemoglobin A(1c), disease duration and pubertal stage on BMD changes. Methods: Fifty-eight patients were investigated: 16 had been newly diagnosed (Diabetes(New)) and 42 were already on follow up (Diabetes(Follow up)). BMD of the lumbar vertebrae, HbA1c(HbA1c(last)), Ca, P, Mg were measured. Mean HbA1c of the previous year (HbA1c(1year)), the whole duration of diabetes (HbA1c(whole)), and diabetic impact index (HbA1c(whole) x diabetes duration) were calculated in the Diabetes(Follow up) group. Results: Mean BMD-Z score (-0.61 +/- 0.99 g/cm(2)) of the whole group was significantly lower than zero. Osteopenia was present in 14 (24.1%), and osteoporosis in three (5.2%). HbA1c(whole) was the most important determinant effecting BMD-Z (r = -0.35, P < 0.05) with the cut-off for osteopenia and osteoporosis being 9.8% and 12.1%, respectively. The cut-off of diabetes duration for osteopenia was 3.6 years and it was more predictive for osteopenia compared to HbA1c(whole). In the Diabetes(New) group, the BMD-Z score of the early pubertal group was significantly lower than those in other pubertal groups. Conclusion: BMD is affected in diabetic children, and HbA1c(whole) and diabetes duration are the most important determinants. Pubertal stage is another determinant of BMD, especially in newly diagnosed patients.