Abstract: Objective To investigate the relationships among bone mineral density,body composition and bone metabolism related factors in normal and obese children and adolescents such as serum 25-hydroxyvitamin D [25-(OH)D],serum alkaline phosphatase(ALP),blood calcium,blood phosphorus,in order to provide reference for clinical assessment. Methods Children aged 6 to 15 years in health examination clinic and obese children′s clinic in Nanjing Children′s Hospital Affiliated to Nanjing Medical University were enrolled in this study from August 2017 to September 2018. Bone density was measured using an ultrasonic bone density meter,meanwhile the body composition and various factors related to bone metabolism were measured. Results Totally 1 138 children were enrolled in this study,of whom 606 were in normal body weight group and 532 were in the overweight and obesity group.The detection rate of insufficient bone density was 22.5%(14.7% in normal group and 31.4% in obesity group).And the average bone mineral density in the obesity group was significantly lower than that in normal group (P<0.001).Correlation analysis showed that bone mineral density was negatively correlated with body mass index (BMI) in the normal group (P<0.001),and was positively correlated with 25-(OH)D level (P=0.001).The bone mineral density of obese children was negatively related to BMI,waist-to-height ratio (W/H),percentage of fat mass (FM%) (P<0.001),and was positively related to skeletal muscle% (P=0.008) and 25-(OH)D level(P=0.001).However,bone mineral density was not associated with serum levels of ALP,calcium or phosphorus in normal or obese children (P>0.05). Conclusions Insufficient 25-(OH)D level and obesity,especially abdominal obesity,have impact on the increase of bone density.Serum calcium,phosphorus and ALP levels are not related to bone mineral density in children.

Key words: obesity, bone density, body composition, 25-hydroxyvitamin D, children

摘要： 目的 分析正常和肥胖儿童青少年骨密度与人体成分、骨代谢相关指标血清25-羟维生素D [25-(OH)D]、血清碱性磷酸酶(ALP)、血钙、血磷的相关性,为临床评估儿童骨骼健康提供依据。方法 选择2017年8月-2018年9月在南京医科大学附属儿童医院保健科健康体检门诊和肥胖儿童门诊就诊的6~15岁儿童为研究对象。采用超声骨密度仪检测骨密度。同时测定人体成分及骨代谢相关指标。结果 共纳入儿童1 138 例,其中正常体重组606人,超重肥胖组532人。总体骨密度不足检出率为22.5%(正常组14.7%、肥胖组31.4%);肥胖组儿童平均骨密度明显低于正常组(P<0.001)。相关分析显示,正常组儿童骨密度与体重指数(BMI)呈负相关(P<0.001),与25-(OH)D呈正相关(P=0.001)。而肥胖儿童骨密度与BMI、腰围身高比(W/H)、体脂%(FM%)均呈负相关(P<0.001),与骨骼肌%(P=0.008)、25-(OH)D水平(P=0.001)均呈正相关,无论正常或肥胖儿童,骨密度与血清ALP、钙、磷的相关性不显著(P>0.05)。结论 儿童25-(OH)D水平不足和肥胖尤其是腹型肥胖均可影响骨密度的增加;血清钙、磷、ALP与儿童骨密度无关。

关键词: 肥胖, 骨密度, 人体成分, 25-羟维生素D, 儿童