Impact of vitamin D supplementation on cardiometabolic risk in schoolchildren

描述(申请人提供)：维生素D缺乏与心血管疾病的发展有关，据估计，目前有600万儿童缺乏维生素D。由于许多儿童很难达到美国儿科学会提出的每天400国际单位的新建议摄入量，许多人建议补充维生素D是必要的。维生素D缺乏症在北纬地区更加普遍，在一些皮肤颜色较深的少数群体中，以及在超重或肥胖的人群中。在这些人群中，可能需要更高的补充剂量来维持最佳的血清水平，并防止心血管风险。这项拟议工作的总体目标是确定居住在北纬(42Z以上)的儿童的适当维生素D补充需求，以维持25-羟基维生素D[25(OH)D]的最佳血清水平，并将心脏代谢风险降至最低。我们还将首次在随机对照试验中调查停止补充后血清25(OH)D和心脏代谢危险因素的变化。从初冬开始，来自美国东北部肥胖率较高的社会经济贫困和种族多元化社区的四年级八年级儿童将被随机分配到每天400国际单位、1000国际单位或2000国际单位的六个月中。血清25(OH)D和心脏代谢危险因素(血脂和血糖)将在补充前的基线、3个月和6个月，然后在停止补充6个月后再次测量。肥胖、体力活动、维生素D的饮食摄入量和阳光暴晒也将在这些时间段进行评估。这项工作的结果将为制定关于补充维生素D以维持最佳25(OH)D水平和降低心脏代谢风险的循证建议和指南提供信息。如果补充维生素D有可能改善儿童时期的心脏代谢风险，那么我们最终将能够降低儿童在成年后患心血管疾病的风险。

DESCRIPTION (provided by applicant): Vitamin D deficiency has been linked to the development of cardiovascular disease and it is estimated that six million children are currently vitamin D deficient. As it is difficult for many children to consume the new recommended intake of 400 IU/d set forth by the American Academy of Pediatrics, many have suggested that vitamin D supplementation is necessary. Vitamin D deficiency is even more common in northern latitudes, amongst some minority groups with darker skin pigmentation, and in those who are overweight or obese. In these groups, higher supplemental doses may be needed to maintain optimal serum levels and to prevent cardiovascular risk. The overall objective of the proposed work is to determine the appropriate vitamin D supplementation requirements for children living at northern latitudes (above 42Z) to maintain optimal serum levels of 25-hydroxyvitamin D [25(OH)D] and minimize cardiometabolic risk. We will also investigate for the first time in a randomized controlled trial what happens to serum 25(OH)D and cardiometabolic risk factors after supplementation is discontinued. Fourth-eight grade children from socioeconomically disadvantaged and racially diverse communities with high obesity rates in the northeastern U.S. will be randomized to 400 IU, 1000 IU, or 2000 IU/d for six months starting in the early winter. Serum 25(OH)D and cardiometabolic risk factors (blood lipids and glucose) will be measured at baseline prior to supplementation, at 3- and 6-months, and then again 6 months following the discontinuation of supplementation. Adiposity, physical activity, dietary intake of vitamin D, and sun exposure will also be assessed at these times. Results of this work will inform the development of evidence-based recommendations and guidelines regarding vitamin D supplementation to maintain optimal 25(OH)D levels and to reduce cardiometabolic risk. If vitamin D repletion has the potential to improve the cardiometabolic risk profile during childhood, then we will ultimately be able to lower a child's risk of developing cardiovascular disease in adulthood.