Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA.
J Bone Miner Res. 2010 Jul;25(7):1527-35. doi: 10.1002/jbmr.43.
Black adults have higher bone mass than whites in the United States, but it is not clear when black children gain bone mineral faster than white children. We performed a cohort study to compare the growth velocity of total-body bone mineral content (TBMC) between black and white children of the same sex at different ages and stages of sexual maturity. TBMC and total-body area were measured in a cohort of 188 black and white boys and girls aged 5 to 15 years annually for up to 4 years. Rates of change in TBMC and area were found to vary with age and with Tanner stage. For both TBMC and area, growth velocities between black and white children differed significantly across Tanner stages. Age-specific velocities were higher in black children during prepuberty and initial entry into puberty but reversed in subsequent Tanner stages. Despite earlier entry into each Tanner stage, black children spent only an average of only 0.2 year longer in Tanner stages II through IV, and total gain in TBMC from age 5 to 15 was not higher in whites. In conclusion, the higher bone mass in black adults compared with whites cannot be attributed to faster accrual during puberty. It is due to black children's higher rate of bone mineral accrual in prepuberty and plausibly in postpuberty. Most of the racial difference in TBMC velocity can be explained by growth in size.
美国的黑人成年人的骨量比白人高，但目前尚不清楚黑人儿童的骨矿物质积累速度何时比白人儿童快。我们进行了一项队列研究，比较了不同性别、不同性成熟阶段的同年龄黑人儿童和白人儿童的全身骨矿物质含量（TBMC）的生长速度。我们对 188 名年龄在 5 至 15 岁的黑人和白人男孩和女孩进行了队列研究，每年测量一次 TBMC 和全身面积，最长达 4 年。结果发现，TBMC 和面积的变化率随年龄和 Tanner 阶段而变化。对于 TBMC 和面积，黑人和白人儿童之间的生长速度在 Tanner 阶段存在显著差异。在青春期前和青春期初期，黑人儿童的特定年龄速度较高，但在随后的 Tanner 阶段则相反。尽管黑人儿童更早进入每个 Tanner 阶段，但他们在 Tanner 阶段 II 到 IV 期间只平均多花了 0.2 年的时间，而且从 5 岁到 15 岁，白人儿童的 TBMC 总增长量并没有更高。总之，与白人相比，黑人成年人更高的骨量不能归因于青春期更快的积累。这是由于黑人儿童在青春期前和可能在青春期后具有更高的骨矿物质积累率。TBMC 速度的大部分种族差异可以用生长大小来解释。
