关键词: 肥胖, 骨密度, 人体成分, 25-羟维生素D, 儿童

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