The relationship between different metabolic phenotypes and bone indices in Chinese children and adolescents aged 12-18 years old

Data regarding different metabolic phenotypes and bone markers including bone mineral content (BMC) and osteocalcin (OCN) among children and adolescents are very limited. Hence, the purpose of this investigation was to explore the relationship between different metabolic phenotypes and BMC or OCN among Chinese children and adolescents. This cross-sectional study included 1,328 children and adolescents aged between 12 and 18 years who were selected from four schools in Yinchuan city from 2018 to 2020 by stratified cluster random sampling. Subjects were divided into four groups according to BMI and metabolic status, as follows: metabolically healthy obesity (MHO), metabolically unhealthy obesity (MUO), metabolically unhealthy normal weight (MUNW), and metabolically healthy normal weight (MHNW). The MHNW, MUNW, MHO, and MUO phenotypes in boys were 48.4%, 30.5%, 6.7%, and 14.4%, respectively, and were 47.8%, 33.6%, 6.6%, and 12.1% in girls, respectively. The MHO and MUO phenotypes had higher BMC than the MHNW or MUNW phenotype (all p < 0.05), and the MUO phenotype with BMC was significantly higher than MHO group in boys (p < 0.05). We discovered a significant positive correlation between BMC and the MHO (OR = 8.82, 95% CI = 2.04-38.16), MUO phenotypes (OR = 13.53, 95% CI = 4.10-44.70), while no association was found between OCN and metabolic phenotypes in neither boys nor girls. Overweight/obese children and adolescents had higher BMC, and there existed sex differences in the effect of metabolic status on BMC among them. OCN was not supposed to be an index of bone health in this study.