Department of Nutrition Science, Purdue University, West Lafayette, Indiana.
Department of Medicine, Indiana University, Indianapolis, Indiana.
J Clin Endocrinol Metab. 2019 Mar 1;104(3):892-899. doi: 10.1210/jc.2018-00353.
Insulin resistance is an adverse health outcome that accompanies obesity. Fat mass is negatively associated with the bone mass after adjustment for confounders. Insulin resistance might be an intermediary in this relationship.
To determine whether insulin resistance is an intermediary in the relationship between adiposity and bone mass in adolescents.
Cross-sectional secondary analysis of baseline data from a previous randomized trial.
University research facility.
A total of 240 adolescents (68% female), aged 7 to 15 years.
Using dual energy x-ray absorptiometry, bone mineral content (BMC), areal bone mineral density, lean mass, and fat mass were measured. Skeletal sites of interest included the total body and lumbar spine (LS). Waist circumference was measured using an anthropometric tape measure. Insulin and glucose were measured in fasting sera, and the homeostasis model assessment of insulin resistance (HOMA-IR) was calculated. Path analysis was performed to determine whether the relationship between adiposity and bone was mediated through insulin resistance.
Fat mass (r = 0.467; P < 0.001) and waist circumference (r = 0.487; P < 0.001) correlated positively with HOMA-IR. Controlling for race, sex, maturation, lean mass, and height, fat mass, waist circumference, and HOMA-IR were negatively associated with LS BMC and total body areal bone mineral density (P < 0.05 for all). Additionally, path models for fat mass (95% CI, -5.893 to -0.956) and waist circumference (95% CI, -15.473 to -2.124) showed a negative relationship with LS BMC via HOMA-IR.
These results support an intermediary role of insulin resistance in the relationship between adiposity and LS bone mass.
胰岛素抵抗是肥胖伴随的一种不良健康后果。在调整混杂因素后，脂肪量与骨量呈负相关。胰岛素抵抗可能是这种关系的中间环节。
确定胰岛素抵抗是否是青少年肥胖与骨量之间关系的中间环节。
对先前随机试验的基线数据进行的横断面二次分析。
大学研究机构。
共 240 名青少年（68%为女性），年龄 7 至 15 岁。
使用双能 X 射线吸收法测量骨矿物质含量（BMC）、面积骨矿物质密度、瘦体重和脂肪量。感兴趣的骨骼部位包括全身和腰椎（LS）。使用人体测量带测量腰围。空腹血清中测量胰岛素和葡萄糖，并计算胰岛素抵抗的稳态模型评估（HOMA-IR）。路径分析用于确定肥胖与骨之间的关系是否通过胰岛素抵抗介导。
脂肪量（r = 0.467；P < 0.001）和腰围（r = 0.487；P < 0.001）与 HOMA-IR 呈正相关。在控制种族、性别、成熟度、瘦体重和身高后，脂肪量、腰围和 HOMA-IR 与 LS BMC 和全身面积骨矿物质密度呈负相关（所有 P < 0.05）。此外，脂肪量（95%CI，-5.893 至-0.956）和腰围（95%CI，-15.473 至-2.124）的路径模型显示，HOMA-IR 与 LS BMC 呈负相关。
这些结果支持胰岛素抵抗在肥胖与 LS 骨量之间关系中起中间作用。
