Brookes Denise S K, Briody Julie N, Davies Peter S W, Hill Rebecca J
*Faculty of Medicine and Biological Sciences, Children's Nutrition Research Centre, The University of Queensland†School of Medicine, The University of Queensland, Brisbane‡The Children's Hospital at Westmead, Sydney, Australia.
J Pediatr Gastroenterol Nutr. 2016 Jul;63(1):113-7. doi: 10.1097/MPG.0000000000001135.
Young individuals with Crohn disease (CD) are at risk of poor bone mineral density (BMD) and reduced lean tissue mass (LTM). The importance of LTM for maintaining skeletal health, in both incident and established CD, is evidenced. We used dual-energy x-ray absorptiometry assessment to identify areal BMD and LTM in individuals with CD.
In 57 patients with CD (15F; 12.99-14.16 years) anthropometric, disease activity, bone age assessment, and total body dual-energy x-ray absorptiometry measurements were acquired. A 4-step algorithm was used to assess simultaneous bone and body composition data: areal BMD and height z scores, and LTM for height and bone mineral content (BMC) for LTM z scores were calculated. Low z score cut-off values were defined as ≤1 standard deviations below the population means.
The CD cohort showed: low areal BMD z scores (P = 0.00); and low LTM for height (P = 0.00) according to defined cut-off values. BMC appeared to be adapting for the lower amount of LTM. Correcting for bone age eliminated the low areal BMD z scores. As expected, LTM for height and BMC for LTM z scores remained unchanged.
We present a useful clinical algorithm to show significant LTM for height deficits, regardless of chronological or bone age, in this CD cohort. BMC seemed to adapt to the reduced LTM, indicating clinically "normal" areal BMD for age when considered for height. The ongoing deficits in LTM may, however, create chronic long-term consequences for bone health. Improving LTM should be a focus of clinical treatment in individuals with CD.
患有克罗恩病（CD）的年轻人存在骨矿物质密度（BMD）低和瘦组织质量（LTM）降低的风险。LTM对新发和已确诊CD患者维持骨骼健康的重要性已得到证实。我们使用双能X线吸收法评估来确定CD患者的面积骨密度和LTM。
对57例CD患者（15名女性；年龄12.99 - 14.16岁）进行人体测量、疾病活动度、骨龄评估及全身双能X线吸收法测量。采用一种四步算法来评估骨骼和身体成分数据：计算面积骨密度和身高z评分，以及身高的LTM和LTM的骨矿物质含量（BMC）的z评分。低z评分临界值定义为低于人群均值1个标准差以上。
根据定义的临界值，CD队列显示：面积骨密度z评分低（P = 0.00）；身高的LTM低（P = 0.00）。BMC似乎在适应较低的LTM量。校正骨龄后消除了低面积骨密度z评分。正如预期的那样，身高的LTM和LTM的BMC的z评分保持不变。
我们提出了一种有用的临床算法，以显示该CD队列中无论实际年龄或骨龄如何，身高的LTM均显著降低。BMC似乎适应了降低的LTM，表明考虑身高时年龄的面积骨密度在临床上“正常”。然而，LTM的持续降低可能会对骨骼健康产生慢性长期影响。改善LTM应成为CD患者临床治疗的重点。
