ABSTRACT
BACKGROUND AND AIM: Adults with type 1 diabetes (T1D) have increased risk of bone fractures and decreased bone mineral density (BMD). Alterations in bone turnover have been suggested as the link between T1D and the impaired bone health. Furthermore, bone turnover has been suggested to have beneficial effects on glucose metabolism. This study aimed at describing bone turnover markers (BTM), and the relationship with glycemic control, in children and adolescents with T1D. METHODS: A total of 173 (47% girls) children and adolescents aged 7.7 to 17.5 years with T1D for more than 1 year were included. Participants were evaluated by BMD together with measurements of selected BTM; two formation markers: osteocalcin (OCN) and procollagen type-1 amino-terminal propeptide (P1NP) and one resorption marker, C-terminal cross-linked telopeptide of type-1 collagen (CTX). BTM were converted into Z-scores utilizing new national references. RESULTS: Mean OCN Z-score (-0.68 ± 1.31), P1NP Z-score (-0.33 ± 1.03) and CTX Z-score (-0.43 ± 1.10) were all significantly lower than the reference population (P < .001). No associations were seen between BTM and T1D duration. BMD Z-score was comparable to the reference population and associated with none of individual BTMs. CTX Z-score was negatively associated with HbA1c (P = .007) independent of both exogenous and residual endogenous insulin. CONCLUSIONS: Markers of bone formation and resorption were decreased in children and adolescents with T1D. CTX Z-score associated negatively with HbA1c adjusted for insulin treatment and endogenous insulin production indicating a potential association between CTX and insulin sensitivity. The long-term consequences of decreased BTM on BMD need further attention.
Subject(s)
Biomarkers/blood , Bone Remodeling/physiology , Diabetes Mellitus, Type 1/blood , Adolescent , Adult , Biomarkers/analysis , Bone Density/physiology , Child , Child, Preschool , Cohort Studies , Collagen Type I/blood , Diabetes Mellitus, Type 1/metabolism , Diabetes Mellitus, Type 1/physiopathology , Down-Regulation , Female , Glycemic Control , Humans , Male , Osteocalcin/blood , Peptide Fragments/blood , Peptides/blood , Procollagen/blood , Young AdultABSTRACT
AIMS: Adults with type 1 diabetes mellitus (T1D) have decreased bone mineral density (BMD). Our study aimed at determining BMD and the association to metabolic control in children and adolescents with T1D. METHODS: 244 patients (113 girls) with a median age of 14.3 years and T1D duration of 1-16 years were included. A dual-energy X-ray absorptiometry scan assessed BMD Z-scores excluding the head (total body less head, TBLH). TBLH-BMD were then investigated for associations to diabetes relevant variables such as HbA1c, insulin treatment, anthropometry and physical activity. RESULTS: In all participants the TBLH-BMD Z-score (0.22 ± 0.96) was significantly higher than the references. Separated by sex, TBLH-BMD Z-score in boys (0.11 ± 0.84) was no different from healthy peers whereas TBLH-BMD Z-score was significantly higher in girls (0.36 ± 1.09). The higher TBLH-BMD Z-score in girls were explained by higher BMI Z-scores. Participants with assumed final height (based on age) had an average TBLH-BMD Z-score of 0.78 ± 1.06, significantly higher than references independent of gender, HbA1c, height- and weight Z-scores. Multiple regression analyses showed that TBLH BMD Z-score associated negatively to HbA1c (P = 0.003), pump treatment (P = 0.019) and screen-time (P = 0.005) and positively to weight Z-score (P < 0.001). Physical activity, sex and puberty did not significantly associate to TBLH-BMD Z-score. CONCLUSION: Unlike adults with T1D, BMD is not decreased in children and adolescents with T1D and even elevated after attained final height. As HbA1c negatively associates to BMD, decreased BMD may progress over time. Whether changes in microarchitecture or bone metabolism precede changes in BMD needs further investigation.
