Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China; Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA.
Department of Epidemiology, Capital Institute of Pediatrics, Beijing, China.
Bone. 2019 Apr;121:259-266. doi: 10.1016/j.bone.2019.01.027. Epub 2019 Jan 30.
Body mass plays a crucial role in the bone growth and development, but few studies have examined the association of long-term cumulative impact and trajectory patterns of childhood body mass index (BMI) with adult bone mass, and the mediation effect of adult BMI and body composition on these associations. A total of 397 Chinese adults (54.4%) who had been examined for BMI 4-8 times during childhood (6-19 years) and bone mass in adulthood (29-37 years), were included for analysis. Adult bone mineral content (BMC), areal bone mineral density (aBMD) and body composition were assessed via dual-energy x-ray absorptiometry. Childhood BMI growth curves were constructed using a random-effects mixed model. The area under the curve (AUC) was calculated to represent the long-term impact of childhood BMI. At baseline, 24.4%, 66.2%, 7.6% and 1.8% of the participants were underweight, normal weight, overweight and obese, respectively. Quadratic curve parameters of childhood BMI differed significantly between groups of adult whole body (WB) BMC, lumbar spine (LS) aBMD and femoral neck (FN) aBMD, with low BMC/aBMD groups having lower childhood BMI than the normal groups. AUC of childhood BMI was significantly and positively related to adult WB BMC and aBMD at each site, irrespective of sex. Significant mediation effects of adult BMI were shown on the association of childhood BMI AUC with adult WB BMC in males (52.0%) and FN aBMD in both sexes (males: 65.4%; females: 64.3%). Additionally, mediation effect of fat mass index was only noted on the association of childhood BMI AUC with adult WB BMC (41.3%), with a positive total indirect effect estimated at 0.118. The adult lean mass index, by contrast, mediated the childhood BMI-adult BMC/aBMD association positively at all sites in males (71.5%~89.2%) and at WB BMC in females (45.0%). These findings suggest that the impact of body weight on adult bones originates from childhood, which is mediated by concurrent BMI and body composition.
体重在骨骼生长和发育中起着至关重要的作用，但很少有研究检查儿童期体重指数（BMI）的长期累积影响和轨迹模式与成人骨量之间的关系，以及成人 BMI 和身体成分对这些关系的中介作用。共有 397 名中国成年人（54.4%）在儿童期（6-19 岁）接受了 4-8 次 BMI 检查，并在成年期（29-37 岁）接受了骨量检查，这些人被纳入分析。通过双能 X 射线吸收法评估成人骨矿物质含量（BMC）、面积骨矿物质密度（aBMD）和身体成分。使用随机效应混合模型构建儿童 BMI 生长曲线。计算曲线下面积（AUC）来表示儿童 BMI 的长期影响。在基线时，分别有 24.4%、66.2%、7.6%和 1.8%的参与者体重过轻、正常体重、超重和肥胖。不同成人全身（WB）BMC、腰椎（LS）aBMD 和股骨颈（FN）aBMD 组的儿童 BMI 二次曲线参数存在显著差异，低 BMC/aBMD 组的儿童 BMI 低于正常组。儿童 BMI AUC 与各部位的成人 WB BMC 和 aBMD 呈显著正相关，与性别无关。在男性中，成人 BMI 对儿童 BMI AUC 与成人 WB BMC 之间的关联存在显著的中介作用（52.0%），在两性中，成人 BMI 对儿童 BMI AUC 与 FN aBMD 之间的关联存在显著的中介作用（男性：65.4%；女性：64.3%）。此外，仅在儿童 BMI AUC 与成人 WB BMC 之间的关联中观察到脂肪质量指数的中介作用（41.3%），估计的正向总间接效应为 0.118。相比之下，在男性中，成人瘦体重指数在所有部位（71.5%~89.2%）和女性的 WB BMC 中（45.0%）均正向介导儿童 BMI 与成人 BMC/aBMD 之间的关联。这些发现表明，体重对成人骨骼的影响源于儿童期，这是由当前的 BMI 和身体成分介导的。
