McCormack Shana E, Cousminer Diana L, Chesi Alessandra, Mitchell Jonathan A, Roy Sani M, Kalkwarf Heidi J, Lappe Joan M, Gilsanz Vicente, Oberfield Sharon E, Shepherd John A, Winer Karen K, Kelly Andrea, Grant Struan F A, Zemel Babette S
Division of Endocrinology and Diabetes, Department of Pediatrics, The Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia.
Division of Human Genetics, Department of Pediatrics, The Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia.
JAMA Pediatr. 2017 Sep 5;171(9):e171769. doi: 10.1001/jamapediatrics.2017.1769.
Prevention of osteoporosis in adulthood begins with optimizing bone health in early life. The longitudinal association between growth and bone accretion during childhood is not fully understood.
To assess the acquisition of whole-body (WB) and skeletal site-specific bone mineral content (BMC) relative to linear growth in a healthy, diverse, longitudinal cohort of children, adolescents, and young adults and to test for differences related to sex and African American race.
DESIGN, SETTING, AND PARTICIPANTS: This investigation was a mixed longitudinal study with annual assessments for up to 7 years at 5 US clinical centers. Participants were healthy children, adolescents, and young adults. The study dates were July 2002 through March 2010. The dates of the analysis were June through December 2016.
Anthropometrics, BMC, and body composition via dual-energy x-ray absorptiometry. The superimposition by translation and rotation (SITAR) analysis method was used to define the mean trajectories for height, WB lean soft tissue, appendicular lean soft tissue, and WB and skeletal site-specific BMC acquisition and to measure the age and magnitude of peak velocity for each parameter. The SITAR modeling was performed separately by sex and self-reported race.
Among 2014 healthy children, adolescents, and young adults (1022 [50.7%] female and 479 [23.8%] African American) aged 5 to 19 years at study entry, the mean age of peak height velocity was 13.1 years (95% CI, 13.0-13.2 years) in African American boys vs 13.4 years (95% CI, 13.3-13.4 years) in non-African American boys (difference, -0.3 years; 95% CI, -0.4 to -0.1 years) and 11.0 years (95% CI, 10.8-11.1 years) in African American girls vs 11.6 years (95% CI, 11.5-11.6 years) in non-African American girls (difference, -0.6 years; 95% CI, -0.7 to -0.5 years). Age of peak acquisition of WB BMC was 14.0 years (95% CI, 13.8-14.1 years) in African American boys vs 14.0 years (95% CI, 13.9-14.1 years) in non-African American boys (difference, -0.0 years; 95% CI, -0.2 to 0.2 years) and 12.1 years (95% CI, 12.0-12.3 years) in African American girls vs 12.4 years (95% CI, 12.3-12.5 years) in non-African American girls (difference, -0.3 years; 95% CI, -0.4 to -0.1 years). At age 7 years, children had acquired 69.5% to 74.5% of maximal observed height but only 29.6% to 38.1% of maximal observed WB BMC. Adolescents gained 32.7% to 35.8% of maximal observed WB BMC during the 2 years before and 2 years after peak height velocity. Another 6.9% to 10.7% of maximal observed WB BMC occurred after linear growth had ceased. In the group at highest risk for fracture, non-African American boys, peak fracture incidence occurred approximately 1 year before peak height velocity.
In this longitudinal study, height gains substantially outpaced gains in BMC during childhood, which could contribute to fracture risk. A significant proportion of bone is accrued after adult height is achieved. Therefore, late adolescence represents a potentially underrecognized window of opportunity to optimize bone mass.
成年期骨质疏松症的预防始于生命早期骨骼健康的优化。儿童时期生长与骨质积累之间的纵向关联尚未完全明确。
在一个健康、多样化的儿童、青少年和青年成年人纵向队列中，评估全身（WB）和特定骨骼部位的骨矿物质含量（BMC）相对于线性生长的获取情况，并测试与性别和非裔美国人种族相关的差异。
设计、地点和参与者：本研究为混合纵向研究，在美国5个临床中心进行了长达7年的年度评估。参与者为健康的儿童、青少年和青年成年人。研究日期为2002年7月至2010年3月。分析日期为2016年6月至12月。
通过双能X线吸收法测量人体测量学指标、BMC和身体成分。采用平移和旋转叠加（SITAR）分析方法来定义身高、WB瘦软组织、四肢瘦软组织以及WB和特定骨骼部位BMC获取的平均轨迹，并测量每个参数的峰值速度的年龄和幅度。SITAR建模按性别和自我报告的种族分别进行。
在研究开始时年龄为5至19岁的2014名健康儿童、青少年和青年成年人中（1022名[50.7%]为女性，479名[23.8%]为非裔美国人），非裔美国男孩的身高峰值速度平均年龄为13.1岁（95%CI，13.0 - 13.2岁），而非非裔美国男孩为13.4岁（95%CI，13.3 - 13.4岁）（差异为 - 0.3岁；95%CI， - 0.4至 - 0.1岁）；非裔美国女孩为11.0岁（95%CI，10.8 - 11.1岁），而非非裔美国女孩为11.6岁（95%CI，11.5 - 11.6岁）（差异为 - 0.6岁；95%CI， - 0.7至 - 0.5岁）。WB BMC获取峰值年龄在非裔美国男孩中为14.0岁（95%CI，13.8 - 14.1岁），非非裔美国男孩为14.0岁（95%CI，13.9 - 14.1岁）（差异为 - 0.0岁；95%CI， - 0.2至0.2岁）；非裔美国女孩为12.1岁（95%CI，12.0 - 12.3岁），非非裔美国女孩为12.4岁（95%CI，12.3 - 12.5岁）（差异为 - 0.3岁；95%CI， - 0.4至 - 0.1岁）。在7岁时，儿童已获得最大观察身高的69.5%至74.5%，但仅获得最大观察WB BMC的29.6%至38.1%。青少年在身高峰值速度前2年和后2年期间获得了最大观察WB BMC的32.7%至35.8%。在最大观察WB BMC中，另有6.9%至10.7%是在线性生长停止后获得的。在骨折风险最高的组（非非裔美国男孩）中，骨折发病率峰值大约出现在身高峰值速度前1年。
在这项纵向研究中，儿童期身高增长显著超过BMC增长，这可能导致骨折风险增加。相当一部分骨质是在达到成人身高后积累的。因此，青春期晚期是优化骨量的一个可能未得到充分认识的机会窗口。
