[Evolution of bone mass in children and adolescents with type 1 diabetes mellitus]

Higher levels of s-RANKL and osteoprotegerin in children and adolescents with type 1 diabetes mellitus may indicate increased osteoclast signaling and predisposition to lower bone mass: a multivariate cross-sectional analysis

Simultaneous lower bone mineral density, metabolic bone markers, parathyroid hormone (PTH), magnesium, insulin-like growth factor 1 (IGF1), and higher levels of total soluble receptor activator of nuclear factor-kappa B ligand (s-RANKL), osteoprotegerin (OPG), and alkaline phosphatase (ALP) are indicative of lower osteoblast and increased osteoclast signaling in children and adolescents with type 1 diabetes mellitus, predisposing to adult osteopenia and osteoporosis.

INTRODUCTION

Type 1 diabetes mellitus (T1DM) is a risk factor for reduced bone mass, disrupting several bone metabolic pathways. We aimed at identifying association patterns between bone metabolic markers, particularly OPG, s-RANKL, and bone mineral density (BMD) in T1DM children and adolescents, in order to study possible underlying pathophysiologic mechanisms of bone loss.

METHODS

We evaluated 40 children and adolescents with T1DM (mean ± SD age 13.04 ± 3.53 years, T1DM duration 5.15 ± 3.33 years) and 40 healthy age- and gender-matched controls (aged12.99 ± 3.3 years). OPG, s-RANKL, osteocalcin, C-telopeptide cross-links (CTX), IGF1, electrolytes, PTH, and total 25(OH)D were measured, and total body along with lumbar spine BMD were evaluated with dual energy X-ray absorptiometry (DXA). Multivariate regression and factor analysis were performed after classic inference.

RESULTS

Patients had significantly lower BMD, with lower bone turnover markers, PTH, magnesium, and IGF1 than controls, indicating lower osteoblast signaling. Higher levels of total s-RANKL, OPG, and total ALP were observed in patients, with log(s-RANKL) and OPG correlation found only in controls, possibly indicating increased osteoclast signaling in patients. Coupling of bone resorption and formation was observed in both groups. Multivariate regression confirmed simultaneous lower bone turnover, IGF1, magnesium, and higher total s-RANKL, OPG, and ALP in patients, while factor analysis indicated possible activation of RANK/RANKL/OPG system in patients and its association with magnesium and IGF1. Patients with longer disease duration or worse metabolic control had lower BMD.

CONCLUSIONS

T1DM children and adolescents have impaired bone metabolism which seems to be multifactorial. Reduced osteoblast and increased osteoclast signaling, resulting from multiple simultaneous disturbances, could lead to reduced peak bone accrual in early adulthood, predisposing to adult osteopenia and osteoporosis.

Fatores socioeconômicos, demográficos, nutricionais e de atividade física no controle glicêmico de adolescentes portadores de diabetes melito tipo 1

OBJETIVO: Identificar a associação de condições socioeconômicas, demográficas, nutricionais e de atividade física sobre o controle glicêmico de adolescentes portadores de DM1. SUJEITOS E MÉTODOS: Estudo transversal com 71 adolescentes com diagnóstico clínico de diabetes tipo 1. Foram obtidos dados socioeconômicos, demográficos e antropométricos. O controle glicêmico foi classificado pelo índice de hemoglobina glicada (A1C). Foram aplicados quatro recordatórios de 24 horas de consumo alimentar e de atividade física. RESULTADOS: A A1C foi inadequada para a maioria dos adolescentes. A menor escolaridade do cuidador influenciou para o controle glicêmico inadequado. Pacientes com menor dose de insulina apresentaram melhor controle glicêmico. A alimentação observada foi hipoglicídica e hiperlipídica. A maioria dos pacientes era sedentária. CONCLUSÃO: Fatores relacionados à educação, à insulina e à alimentação influenciaram no controle glicêmico.

Bone status in adolescents with type 1 diabetes

AIMS

The aim of the study was to investigate the potential negative impact of type 1 diabetes on bone status of adolescents. Bone status in adolescents with type 1 diabetes was assessed by means of quantitative ultrasound (QUS) and the influence of metabolic control and other disease-related and growth variables was analysed.

METHODS

Group I consisted of 99 pubertal (Tanner > or = 2) adolescents (49 female), aged 14.3 +/- 2.5 years, diabetes duration 4.6 +/- 2.3 years. Controls (group II) were 297 children, matched by sex and age, from a healthy population. The influence of glycated haemoglobin (current: HbA(1c)D; last year's mean: HbA(1c)Y; whole duration mean: HbA(1c)T), diabetes duration, percentage of life with disease and daily insulin requirement (DIR) on amplitude dependent speed of sound (Ad-SoS) at distal phalanges was studied.

RESULTS

In comparison to the control group, adolescents with type 1 diabetes presented significantly higher BMI SDS (0.82 [95% CI 0.54, 1.10] vs -0.06 [95% CI -0.16, 0.04] p < 0.001) and lower Ad-SoS SDS (-0.34 [95% CI -0.57, -0.11] vs -0.03 [95% CI -0.15, 0.08], p < 0.05). No correlation between Ad-SoS SDS and sex, DIR or diabetes duration was observed. The lower Ad-SoS SDS reflects reduced bone status, and the reduction was significantly more marked in those patients whose HbA(1c)T was higher than 7.0% when compared with those whose HbA(1c)T was lower.

CONCLUSIONS

Bone status of adolescents with type 1 diabetes mellitus assessed with QUS differs from that of healthy peers and is dependent on long-term metabolic control.