South African Medical Research Council/Wits Developmental Pathways for Health Research Unit, Department of Paediatrics, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
J Bone Miner Res. 2017 Sep;32(9):1926-1934. doi: 10.1002/jbmr.3179. Epub 2017 Jul 5.
To monitor the drift of the periosteal and endocortical surfaces during metacarpal growth longitudinally, radiogrammetry was carried out on hand-wrist X-rays of 572 children from the Birth to Twenty Bone Health Cohort annually from ages 9 to 21 years. This is the largest collection of longitudinal X-rays in African children. The second metacarpal bone length, bone width, and medullary width were measured using digital vernier calipers on a total of 4730 X-rays. Superimposition by Translation and Rotation (SITAR) was used to obtain age at peak metacarpal length velocity (PLV). Bone width and medullary width were modeled using SITAR against both chronological age and age from PLV. In black and white females, tempo and velocity of metacarpal length growth was synchronized. Black males, however, attained PLV 7 months later than white males (p < 0.0001). Compared to white males, black males had a longer second metacarpal (p < 0.05), and greater bone width size (p < 0.02), tempo (p < 0.0009), and velocity (p < 0.0001). Medullary width growth velocity in black participants peaked 2 years prior to attainment of PLV and exceeded that of their white peers (p < 0.0001) in whom it peaked 6 to 12 months post-PLV attainment. Black adolescents therefore had wider bones with relatively thinner cortices and wider medullary cavities than their white peers. Ethnic and sex differences also occurred in the timing of medullary width contraction that accompanied expansion in bone width and cortical thickness. In black males, medullary width contraction commenced approximately 3 years later than in black females, whereas in white males this occurred a year later than in white females. The ethnic and sex differences in bone acquisition reported in this study may differentially affect bone mass in later life. © 2017 American Society for Bone and Mineral Research.
为了监测掌骨生长过程中骨膜和内皮质表面的漂移，我们每年对来自出生至二十岁骨骼健康队列（Birth to Twenty Bone Health Cohort）的 572 名儿童的手和腕部 X 射线进行放射测量，从 9 岁到 21 岁。这是非洲儿童最大的纵向 X 射线集合。我们使用数字游标卡尺总共测量了 4730 张 X 射线片中第二掌骨的长度、宽度和髓腔宽度。使用平移和旋转叠加（Translation and Rotation Superimposition，SITAR）来获得峰值掌骨长度生长速度（Peak Metacarpal Length Velocity，PLV）的年龄。使用 SITAR 根据年龄和 PLV 来构建骨宽度和髓腔宽度模型。在黑人女性中，掌骨长度生长的时间和速度是同步的。然而，黑人男性达到 PLV 的时间比白人男性晚 7 个月（p<0.0001）。与白人男性相比，黑人男性的第二掌骨更长（p<0.05），骨宽度更大（p<0.02），时间更快（p<0.0009），速度也更快（p<0.0001）。黑人参与者的髓腔宽度生长速度在达到 PLV 前 2 年达到峰值，超过了他们的白人同龄人（p<0.0001），白人同龄人的峰值出现在达到 PLV 后 6 至 12 个月。因此，黑人青少年的骨骼比白人同龄人更宽，皮质相对更薄，髓腔更宽。髓腔宽度收缩的时间也存在种族和性别差异，髓腔宽度收缩伴随着骨宽度和皮质厚度的扩张。在黑人男性中，髓腔宽度收缩开始的时间比黑人女性晚大约 3 年，而在白人男性中，开始的时间比白人女性晚 1 年。本研究报告的种族和性别差异在骨骼获取方面可能会对以后的生活中的骨量产生不同的影响。
