Öhlund Inger, Lind Torbjörn, Hernell Olle, Silfverdal Sven-Arne, Karlsland Åkeson Pia
Department of Clinical Sciences, Pediatrics, Umeå University, Umeå, Sweden; and
Department of Clinical Sciences, Pediatrics, Umeå University, Umeå, Sweden; and.
Am J Clin Nutr. 2017 Jul;106(1):105-112. doi: 10.3945/ajcn.116.147108. Epub 2017 Jun 14.
Dark skin and low exposure to sunlight increase the risk of vitamin D insufficiency in children. The aim of the study was to evaluate the amount of vitamin D needed to ascertain that most children >4 y of age attain sufficient serum 25-hydroxyvitamin D [S-25(OH)D; i.e., ≥50 nmol/L] during winter regardless of latitude and skin color. In a longitudinal, double-blind, randomized, food-based intervention study, 5- to 7-y-old children from northern (63°N) and southern (55°N) Sweden with fair ( = 108) and dark ( = 98) skin were included. Children, stratified by skin color by using Fitzpatrick's definition, were randomly assigned to receive milk-based vitamin D supplements that provided 2 (placebo), 10, or 25 μg/d during 3 winter months. Mean daily vitamin D intake increased from 6 to 17 μg and 26 μg in the intervention groups supplemented with 10 and 25 μg, respectively. In the intention-to-treat analysis, 90.2% (95% CI: 81.1%, 99.3%) of fair-skinned children randomly assigned to supplementation of 10 μg/d attained sufficient concentrations, whereas 25 μg/d was needed in dark-skinned children to reach sufficiency in 95.1% (95% CI: 88.5%, 100%). In children adherent to the study product, 97% (95% CI: 91.3%, 100%) and 87.9% (95% CI: 76.8%, 99%) of fair- and dark-skinned children, respectively, achieved sufficient concentrations if supplemented with 10 μg/d. By using 95% prediction intervals for 30 and 50 nmol S-25(OH)D/L, intakes of 6 and 20 μg/d are required in fair-skinned children, whereas 14 and 28 μg/d are required in children with dark skin. Children with fair and dark skin require vitamin D intakes of 20 and 28 μg/d, respectively, to maintain S-25(OH)D ≥50 nmol/L, whereas intakes of 6 and 14 μg/d, respectively, are required to maintain concentrations ≥30 nmol/L during winter. This trial was registered at clinicaltrials.gov as NCT01741324.
肤色较深以及日照不足会增加儿童维生素D缺乏的风险。本研究旨在评估为确保大多数4岁以上儿童在冬季无论纬度和肤色如何都能达到足够的血清25-羟基维生素D [S-25(OH)D；即≥50 nmol/L] 所需的维生素D量。在一项纵向、双盲、随机、基于食物的干预研究中，纳入了来自瑞典北部（北纬63°）和南部（北纬55°）的5至7岁儿童，其中肤色浅的儿童有108名，肤色深的儿童有98名。根据Fitzpatrick定义按肤色分层的儿童被随机分配接受以牛奶为基础的维生素D补充剂，在3个冬季月份中每日分别提供2 μg（安慰剂）、10 μg或25 μg。在补充10 μg和25 μg的干预组中，平均每日维生素D摄入量分别从6 μg增加到17 μg和26 μg。在意向性分析中，随机分配接受每日补充10 μg的肤色浅的儿童中，90.2%（95% CI：81.1%，99.3%）达到了足够的浓度，而肤色深的儿童需要每日补充25 μg才能使95.1%（95% CI：88.5%，100%）的儿童达到充足水平。在坚持服用研究产品的儿童中，如果每日补充10 μg，肤色浅和肤色深的儿童分别有97%（95% CI：91.3%，100%）和87.9%（95% CI：76.8%，99%）达到了足够的浓度。通过使用30和50 nmol S-25(OH)D/L的95%预测区间，肤色浅的儿童分别需要每日摄入6 μg和20 μg，而肤色深的儿童分别需要每日摄入14 μg和28 μg。肤色浅和肤色深的儿童分别需要每日摄入20 μg和28 μg的维生素D以维持S-25(OH)D≥50 nmol/L，而在冬季分别需要每日摄入6 μg和14 μg以维持浓度≥30 nmol/L。该试验已在clinicaltrials.gov上注册，注册号为NCT01741324。
