Prevalence of low bone mass among adolescents with nontransfusion-dependent hemoglobin E/ß-thalassemia and its relationship with anemia severity.

BACKGROUND: Low bone mass is common among adolescents with transfusion-dependent ß-thalassemia despite adequate transfusion and iron chelation. However, there are few reports regarding bone mineral density (BMD) among adolescents with nontransfusion-dependent thalassemia (NTDT). Indeed, only BMD data in patients with nontransfusion-dependent (NTD) ß-thalassemia intermedia have been reported. No previous study has investigated BMD among adolescents with NTD hemoglobin (Hb) E/ß-thalassemia. OBJECTIVE: To determine the prevalence of low bone mass among adolescents with NTD Hb E/ß-thalassemia and factors relating to low bone mass. METHODS: We investigated BMD of lumbar spine (L2-L4; BMDLS) and total body (BMDTB), as measured by dual-energy X-ray absorptiometry, in 22 adolescents (aged 13.2-20 years) with NTD Hb E/ß-thalassemia. RESULTS: Low bone mass was found to be 18.2% and 22.7% at the lumbar spine (BMDLS Z-score adjusted for bone age and height age) and 13.6% and 9.1% at the total body (BMDTB Z-score adjusted for bone age and height age). Patients with mean Hb level <8 g/dl were more likely to have low bone mass (BMDLS and BMDTB Z-scores adjusted for bone age) compared to those with Hb level ≥ 8 g/dl. Mean Hb level correlated with BMDLS and BMDTB Z-scores adjusted for bone age. CONCLUSION: We demonstrated that a low Hb level was associated with low bone mass among adolescents with NTD Hb E/ß-thalassemia. A significant proportion of low bone mass among these patients highlights the importance of appropriate management, including red cell transfusion, vitamin D and calcium supplementation for improved long-term bone health.

Reference values of bone mineral density of proximal femur for Southeast Asian children and adolescents.

Bone mineral density (BMD) of the proximal femur helps evaluate bone density in children with reduced mechanical loading of the lower extremities. This study provides the first reference values of bone mineral density of proximal femur according to age and sex for Southeast Asian children and adolescents.   OBJECTIVES: The study aimed to (1) establish normative data of BMD of the proximal femur (femoral neck and total hip), measured by dual-energy X-ray absorptiometry (DXA), for healthy Thai children aged 5 to 18 years and (2) ascertain the relationships between BMD, growth, and puberty. METHODS: Proximal femur scans of 170 boys and 191 girls obtained from DXA (Lunar Prodigy Pro, GE, and software enCORE version 7.53) were un-analyzed and then re-analyzed with the upgraded software enCORE version 17 SP2 for BMD assessment. The bone mineral apparent density of the femoral neck (FNBMAD) was calculated. RESULTS: Sex and Tanner stage-specific BMD normative data were generated. BMD values of the femoral neck and total hip increased with age and pubertal progression. FNBMAD values were not markedly influenced by age and puberty. Using multiple linear regression analysis, age and weight affected FNBMD and total hip BMD in boys and girls, but height and Tanner stage only influenced girls. Age did not significantly influence FNBMAD in either sex. Tanner stage weakly influenced FNBMAD only in boys. CONCLUSIONS: We established normative reference data for BMD of the proximal femur measured by DXA in Thai children aged 5 to 18 years. Our reference data will help clinicians and researchers assess and interpret the BMD of the proximal femur for Southeast Asian children.

Effect of gender, diabetes duration, inflammatory cytokines, and vitamin D level on bone mineral density among Thai children and adolescents with type 1 diabetes.

INTRODUCTION: Type 1 diabetes mellitus (T1DM) is considered a risk factor for osteoporosis in adults; however, studies in bone mineral density (BMD) in children with T1DM reported conflicting results. The aim of this study was to compare BMD between T1DM youth and healthy controls, and to identify factors that affect BMD in T1DM youth. METHODS: One hundred T1DM youths and 100 healthy controls (both groups aged 5-20 years) were recruited. BMD of total body, lumbar (L2-4), femoral neck, and total hip were assessed using dual energy X-ray absorptiometry. Blood investigations, including hemoglobin A1c (HbA1c), 25-hydroxyvitamin D, and inflammatory cytokines, were performed. RESULTS: Forty-four boys and 56 girls with T1DM were enrolled [mean age 14.5 ±â€¯2.7 years, median (IQR) duration of T1DM 5.80 (2.97-9.07) years, and mean HbA1c entire duration 9.2 ±â€¯1.4%]. T1DM girls had a lower height Z-score than control girls (p < 0.05), and 25-hydroxyvitamin D level was higher in T1DM youth than in controls (p < 0.001). After adjusting for pubertal status, height Z-score, and 25-hydroxyvitamin D, T1DM youth had a significantly lower lumbar BMD Z-score and femoral neck BMD than controls (p = 0.027 and p = 0.025, respectively). We also found that T1DM boys had a significantly lower lumbar BMD Z-score (p = 0.028), femoral neck BMD (p = 0.004), and total hip BMD (p = 0.016) than control boys. In contrast, these significant differences were not found in T1DM girls. Factors affecting BMD were different between T1DM boys and girls, and among different BMD sites. IL-13 was positively correlated with BMD in the total cohort and among girls. In boys - IL-2 and 25-hydroxyvitamin D were positively associated with BMD, and duration of diabetes was found to negatively affect BMD. CONCLUSION: Deleterious effect of T1DM on BMD is gender specific. The longer the duration of T1DM, the greater the deficit in BMD found among boys with T1DM.