BACKGROUND We aimed to establish age- and gender-specific reference ranges for concentrations of the bone markers osteocalcin (OC), procollagen type 1 N-propeptides (PINP) and carboxy-terminal cross-linking telopeptide of type 1 collagen (CTX-I) as well as for the calciotropic hormones 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone (PTH) in healthy infants, children and adolescents. In addition, the effect of age, gender, puberty and body mass index (BMI) on bone markers was investigated. METHODS 2416 healthy subjects (5714 blood withdrawals), aged 3 months to 17 years, were included to estimate the age- and gender-dependence of reference ranges. Subsequently, measured values of the biomarkers were transformed to standard deviation scores (SDS) and their associations with age, gender and puberty were analyzed. Bone marker-SDS values of the reference cohort were compared with an obese cohort (n = 317 and 489 blood withdrawals) to analyze the effect of BMI. RESULTS OC, PINP and CTX-I showed a distinct age- and gender-dependence with peak levels at 10 to 11 years (girls, Tanner 3) and 13 years (boys, Tanner 3-4). Children with obesity had significantly lower SDS levels for OC (-0.44), PINP (-0.27), CTX-I (-0.33), 25(OH)D (-0.43) and higher SDS levels for PTH (+0.44) than the reference cohort. CONCLUSIONS OC, PINP and CTX-I vary with age, gender and pubertal stage. The body weight status has to be considered in the interpretation of pediatric OC, PINP, CTX-I, 25(OH)D and PTH levels. Consequences of childhood obesity on bone health should be carefully investigated in long-term studies.

中文翻译：

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肥胖儿童和青少年的血清骨转换标志物和 25-羟基维生素 D 降低，但甲状旁腺激素浓度增加——结果来自新的儿科参考范围

背景我们旨在为骨标志物骨钙素 (OC)、1 型前胶原 N-前肽 (PINP) 和 1 型胶原的羧基末端交联端肽 (CTX-I) 的浓度建立年龄和性别特异性参考范围以及健康婴儿、儿童和青少年中的促钙激素 25-羟基维生素 D [25(OH)D] 和甲状旁腺激素 (PTH)。此外，还研究了年龄、性别、青春期和体重指数 (BMI) 对骨标志物的影响。方法 2416 名健康受试者（5714 次抽血），年龄在 3 个月到 17 岁之间，被纳入以估计参考范围的年龄和性别依赖性。随后，将生物标志物的测量值转换为标准差评分 (SDS)，并分析它们与年龄、性别和青春期的关联。将参考队列的骨标志物-SDS 值与肥胖队列（n = 317 和 489 次采血）进行比较，以分析 BMI 的影响。结果 OC、PINP 和 CTX-I 显示出明显的年龄和性别依赖性，峰值水平在 10 至 11 岁（女孩，Tanner 3）和 13 岁（男孩，Tanner 3-4）。与肥胖儿童相比，肥胖儿童 OC (-0.44)、PINP (-0.27)、CTX-I (-0.33)、25(OH)D (-0.43) 的 SDS 水平显着降低，PTH (+0.44) 的 SDS 水平更高参考队列。结论 OC、PINP 和 CTX-I 随年龄、性别和青春期阶段而变化。在解释儿科 OC、PINP、CTX-I、25(OH)D 和 PTH 水平时，必须考虑体重状态。应在长期研究中仔细研究儿童肥胖对骨骼健康的影响。