多发性骨折儿童的骨密度和骨代谢评估

Michałus Izabela, Chlebna-Sokół Danuta, Rusińska Agnieszka, Jakubowska-Pietkiewicz Elzbieta, Kulińska-Szukalska Katarzyna

Department of Propedeutics of Paediatrics, Medical University of Lodz.

Ortop Traumatol Rehabil. 2008 Nov-Dec;10(6):602-12.

BACKGROUND

The aim of the study was to carry out a comprehensive analysis of determinants of multiple bone fractures in children with regard to densitometric indices and markers of bone metabolism.

MATERIAL AND METHODS

The study involved 112 children aged 5-18 years, including 81 patients with a history of at least 3 bone fractures and 31 healthy patients in a control group. Total body and spinal DXA densitometry of the skeleton (DPX-L apparatus, Lunar) was carried out in all children. Laboratory assays comprised the determination of calcium, phosphorus, magnesium (in the serum and 24-hour urine collection), parathormone, liver metabolite of vitamin D, osteocalcin, bone alkaline phosphatase, and N-terminal cross-linked telopeptide of collagen type I (NTx).

RESULTS

Mean values of DXA Z-score, both in total body and in spinal scans, were significantly lower in children with multiple fractures as compared to controls. In children with multiple fractures, there was a higher prevalence of hypercalciuria, hypermagnesuria and hyperphosphaturia. Decreased levels of the liver metabolite of vitamin D were observed in 20/81 (24.7%) patients in this group and in 6/31 controls. Other findings included a higher level of NTx in 38/75 (50.7%) patients with fractures, an increased activity of bone alkaline phosphatase in 29, and of osteocalcin in 12 patients. In this group, there was a significant negative correlation between biochemical bone turnover markers and low bone mass. Also, lower DXA Z-scores were found in children with higher urinary calcium excretion.

CONCLUSIONS

Decreased bone mineral density was the most frequent risk factor for bone fractures in children; it was found in about 2/3 of the patients with multiple bone fractures. 2. Accelerated bone turnover, and, particularly, increased bone resorption, indicates a derangement of bone metabolism in children with multiple fractures. 3. Repeated fractures during the body growth period are an indication for a quantitative evaluation of bone mass, calcium-phosphate metabolism and bone turnover markers.

背景

本研究旨在针对骨密度指标和骨代谢标志物，对儿童多发性骨折的决定因素进行全面分析。

材料与方法

本研究纳入了112名5至18岁的儿童，其中包括81名有至少3次骨折病史的患者以及31名作为对照组的健康患者。对所有儿童进行了全身和脊柱的双能X线吸收法骨密度测定（DPX-L仪器，Lunar）。实验室检测包括测定钙、磷、镁（血清及24小时尿样）、甲状旁腺激素、维生素D的肝脏代谢产物、骨钙素、骨碱性磷酸酶以及I型胶原N端交联肽（NTx）。

结果

与对照组相比，多发性骨折儿童的全身和脊柱扫描双能X线吸收法Z值均值显著更低。多发性骨折儿童中，高钙尿症、高镁尿症和高磷尿症的患病率更高。该组20/81（24.7%）的患者以及6/31的对照组患者中观察到维生素D的肝脏代谢产物水平降低。其他发现包括38/75（50.7%）的骨折患者NTx水平更高，29名患者骨碱性磷酸酶活性增加，12名患者骨钙素增加。在该组中，生化骨转换标志物与低骨量之间存在显著的负相关。此外，尿钙排泄较高的儿童双能X线吸收法Z值更低。