Lewis Richard D, Laing Emma M
Department of Foods and Nutrition, The University of Georgia, Room 279 Dawson Hall, Athens, GA 30602, USA.
Department of Foods and Nutrition, The University of Georgia, Room 279 Dawson Hall, Athens, GA 30602, USA.
Mol Cell Endocrinol. 2015 Jul 15;410:11-8. doi: 10.1016/j.mce.2015.03.017. Epub 2015 Mar 26.
A significant number of children and adolescents worldwide have low serum 25(OH)D values relative to the 2010 Institute of Medicine criteria. Since approximately 90% of adult bone mineral content (BMC) is accrued by the end of adolescence, and approximately 40% of adult BMC accumulated during the 4 years surrounding peak BMC velocity, low circulating 25(OH)D during this time may attenuate gains in adolescent bone strength. Reduced bone mineralization and strength during pubertal growth tracks into adulthood and could lead to an increased risk of skeletal fractures. Observational studies examining the relationships between vitamin D and bone are conflicting and few randomized controlled trials (RCTs) have been conducted in children and adolescents. Four of these RCTs, however, provide moderate support for the role of vitamin D supplementation on BMC accrual in adolescent females with baseline serum concentrations <50 nmol/L. Though the daily vitamin D doses employed in these trials ranged from 200 to 3000 IU per day, it is not clear if a dose-response effect exists. Specific maturational stages were associated with optimal bone responses in each of these trials, but they were not consistent across studies. Furthermore, data on male children and among ethnicities other than white and Asian youth were limited in these studies and therefore reduce the generalizability of the findings. Finally, the evidence linking vitamin D supplementation to improved muscle gains and function, important variables to consider in bone health investigations during growth, might imply indirect effects of supplementation on bone. In conclusion, future RCTs are warranted that address the mechanisms by which vitamin D improves bone mineralization in adolescents, including trials that address the impact of vitamin D on muscle function.
相对于2010年美国医学研究所的标准，全球有相当数量的儿童和青少年血清25(OH)D值较低。由于大约90%的成人骨矿物质含量（BMC）在青春期结束时就已积累完成，并且大约40%的成人BMC是在BMC增长速度峰值前后的4年期间积累的，因此在此期间循环25(OH)D水平较低可能会削弱青少年骨骼强度的增加。青春期生长过程中骨矿化和强度的降低会持续到成年期，并可能导致骨骼骨折风险增加。观察性研究中关于维生素D与骨骼之间关系的结果相互矛盾，而且针对儿童和青少年进行的随机对照试验（RCT）很少。然而，其中四项RCT为维生素D补充剂对基线血清浓度<50 nmol/L的青春期女性BMC积累的作用提供了适度支持。尽管这些试验中使用的每日维生素D剂量范围为每天200至3000国际单位，但尚不清楚是否存在剂量反应效应。在这些试验中的每一项中，特定的成熟阶段都与最佳的骨骼反应相关，但各研究之间并不一致。此外，这些研究中关于男童以及白人、亚洲青年以外其他种族的数据有限，因此降低了研究结果的普遍性。最后，将维生素D补充剂与肌肉增加和功能改善联系起来的证据，而肌肉增加和功能是生长期间骨骼健康调查中需要考虑的重要变量，这可能意味着补充剂对骨骼有间接影响。总之，未来有必要进行RCT来研究维生素D改善青少年骨矿化的机制，包括研究维生素D对肌肉功能影响的试验。
