BACKGROUND AND OBJECTIVES: New US Down syndrome (DS) BMI growth charts were recently published, but their utility in identifying children with excess adiposity or increased cardiometabolic risk (CMR) remains unknown. We sought to compare the ability of the Centers for Disease Control and Prevention (CDC) BMI 85th percentile and DS-specific BMI 85th percentile to identify excess adiposity in children with DS.

Context Type 1 diabetes (T1D) is associated with an increased fracture risk across the life course. The effects on bone accrual early in the disease are unknown. Objective To characterize changes in bone density and structure over the year following diagnosis of T1D and to identify contributors to impaired bone accrual. Design Prospective cohort study. Setting Academic children’s hospital. Participants Thirty-six children, ages 7 to 17 years, enrolled at diagnosis of T1D. Outcomes Whole body and regional dual-energy X-ray absorptiometry and tibia peripheral quantitative computed tomography obtained at baseline and 12 months. The primary outcome was bone accrual assessed by bone mineral content (BMC) and areal bone mineral density (aBMD) velocity z score. Results Participants had low total body less head (TBLH) BMC (z = −0.46 ± 0.76), femoral neck aBMD (z = −0.57 ± 0.99), and tibia cortical volumetric BMD (z = −0.44 ± 1.11) at diagnosis, compared with reference data, P < 0.05. TBLH BMC velocity in the year following diagnosis was lower in participants with poor (hemoglobin A1c ≥7.5%) vs good (hemoglobin A1c <7.5%) glycemic control at 12 months, z = −0.36 ± 0.84 vs 0.58 ± 0.71, P = 0.003. TBLH BMC velocity was correlated with gains in tibia cortical area (R = 0.71, P = 0.003) and periosteal circumference (R = 0.67, P = 0.007) z scores in participants with good, but not poor control. Conclusions Our results suggest that the adverse effects of T1D on BMD develop early in the disease. Bone accrual following diagnosis was impaired in participants with poor glycemic control and appeared to be mediated by diminished bone formation on the periosteal surface.

Background The relationship of lipoprotein particle subclasses to visceral adipose tissue area (VAT-area) in obese children has not been examined previously. Objectives The study aims were to compare the relationships of VAT-area, homeostatic model assessment of insulin resistance (HOMA-IR), and body mass index (BMI) with lipids and lipoprotein subclasses in obese adolescents, and to determine if these relationships vary by sex. Methods This cross-sectional study of obese adolescents (BMI≥95th percentile), ages 12-18y, measured VAT-area by dual energy x-ray absorptiometry (DXA), BMI, fasting lipids, lipoprotein subclasses, and HOMA-IR. Linear regression models evaluated the associations of VAT-area, HOMA-IR, and BMI with lipid cardiometabolic risk factors. Sex-stratified analyses further explored these associations. Results Included were 127 adolescents (age=14.4±1.5 years; 53.5% female; 88.2% African-American), mean BMI=34.0±5.1 kg/m2. VAT-area was negatively associated with LDL particle (−P) size (β=−0.28, p=0.0001), HDL-P size (β=−0.33, p<0.0001) and large HDL-P concentration (β=−0.29, p<0.0001), and positively associated with small LDL-P concentration (β=0.23, p=0.0005) and small HDL-P concentration (β=0.25, p=0.05). When VAT-area, HOMA-IR, and BMI associations were compared, VAT-area had the strongest associations with most of the lipoprotein subclasses. After sex-stratification, the associations of VAT-area with HDL cholesterol, LDL-P size, and large LDL-P concentration were significant only for females (all p<0.05). Conclusions In a cohort of largely African-American obese adolescents, VAT-area was associated with a more atherogenic lipoprotein subclass profile. When compared to HOMA-IR and BMI, VAT-area had the strongest associations with most lipoprotein subclasses. The relationships between VAT-area and certain lipoprotein subclasses are significantly different in males versus females.

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