Glycemic control and bone mineral density in children and adolescents with type 1 diabetes

Background/Objective Fracture risk is increased in patients with type 1 diabetes. We aimed to evaluate bone mineral density (BMD) and to identify risk factors associated to lower BMD in Danish children and adolescents with type 1 diabetes. Methods In this cross‐sectional study BMD Z ‐score were determined by dual‐energy X‐ray absorptiometry (DXA) from a cohort of otherwise healthy children and adolescents with type 1 diabetes. Puberty Tanner stage, hemoglobin A1c (HbA1c), disease duration, and age at diabetes onset were investigated for associations to DXA results. Results We included 85 patients, 39 girls, 46 boys, with a median (range) age of 13.2 (6‐17) years; disease duration 4.2 (0.4‐15.9) years; HbA1c of the last year 61.8 (41‐106) mmol/mol. Our patients were taller and heavier than the background population. When adjusted for increased height SD and body mass index SD, no overall difference in BMD Z ‐score was found. When stratified by sex, boys had significantly increased adjusted mean BMD Z‐score, 0.38 (95% confidence interval [CI]: 0.13;0.62), girls; −0.27 (95% CI: −0.53;0.00). For the whole cohort, a negative correlation between mean latest year HbA1c and BMD Z‐score was found, adjusted ß −0.019 (95%CI: −0.034;−0.004, P = 0.01). Poor glycemic control (HbA1c > 58 mmol/mol [7.5%]) within the latest year was likewise negatively correlated with BMD Z‐score, adjusted ß −0.35 (95%CI: −0.69;−0.014, P = 0.04). Conclusions Our study suggests that elevated blood glucose has a negative effect on the bones already before adulthood in patients with type 1 diabetes, although no signs of osteoporosis were identified by DXA.