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Prevention of Vitamin D Deficiency in Breastfed Infants

母乳喂养婴儿维生素 D 缺乏症的预防

基本信息

批准号：
7633393
负责人：
EKHARD E ZIEGLER
金额：
$ 41.79万
依托单位：
UNIVERSITY OF IOWA
依托单位国家：
美国
项目类别：
财政年份：
2006
资助国家：
美国
起止时间：
2006-09-15 至 2011-06-30
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): Vitamin D deficiency occurs among breastfed infants in all parts of the U.S. but is particularly common among infants with dark skin pigmentation and infants living in the northern parts of the U.S. where synthesis of vitamin D in the skin is diminished or absent during winter. The prevalence of vitamin D deficiency, including its severest form, rickets, is on the rise, probably because of the increase in breastfeeding. Vitamin D supplementation can prevent vitamin D deficiency. Current recommendations are to provide a daily supplement of 200 IU of vitamin D. However, it is not established that this dose prevents vitamin D deficiency reliably. Nor is it known how effective higher doses are and what the optimal dose is for infants. The objective of the proposed study is to establish in definitive fashion the effectiveness, or lack thereof, of three vitamin D dosages in the prevention of vitamin D deficiency in breastfed infants. The study will also examine an array of functional indicators of vitamin D sufficiency in the hope of establishing the optimal amount of vitamin D that infants need in order to remain in good health. Infants to whom this applies include infants with dark skin regardless of season and Caucasian infants living at northern latitudes during winter. Breastfed infants will be recruited at 1 month of age and will be assigned at random to receive a daily supplement of either 200 lU/day or 400 lU/day or 600 lU/day from 1 to 9 months of age. They will receive no supplemental formula until age 9 months. This will be a double blind study. Infants will be seen monthly and blood will be drawn by heel stick on seven occasions for determination of 25-OHD and of functional indicators of vitamin D status. Ultraviolet exposure will be estimated also. Bone mineral content will be determined once (in March or April, i.e., at the end of winter). The other endpoints will be measured on multiple occasions. The primary endpoint will be vitamin D status, i.e., plasma concentration of 25-OHD, with deficiency defined as concentration <15 ng/ml. We hypothesize that regular administration of 400 IU and 600 IU of vitamin D each day will prevent vitamin D deficiency reliably but that administration of 200 lU/day will be less than completely effective. Functional indicators of vitamin status will increase with increasing doses of supplemental vitamin D. The study has considerable public health importance because of the importance of preventing vitamin D deficiency not only in its severe form, rickets, but also in its milder forms.

描述（由申请人提供）：维生素D缺乏症发生在美国所有地区的母乳喂养婴儿中，但在皮肤色素沉着较深的婴儿和生活在美国北方地区的婴儿中尤其常见，在这些地区，皮肤中的维生素D合成在冬季减少或缺乏。维生素D缺乏症，包括最常见的佝偻病的发病率正在上升，这可能是由于母乳喂养的增加。补充维生素D可以预防维生素D缺乏症。目前的建议是每天补充200 IU的维生素D。然而，这一剂量不能可靠地预防维生素D缺乏症。也不知道更高剂量的有效性以及婴儿的最佳剂量是多少。本研究的目的是确定三种维生素D剂量在预防母乳喂养婴儿维生素D缺乏症中的有效性或缺乏。该研究还将检查一系列维生素D充足的功能指标，希望确定婴儿保持健康所需的维生素D的最佳量。这适用于皮肤黝黑的婴儿（无论季节如何）和冬季生活在北方纬度的高加索婴儿。母乳喂养的婴儿将在1个月大时招募，并将被随机分配从1至9个月大接受200 IU/天或400 IU/天或600 IU/天的每日补充。他们在9个月大之前不会得到补充配方奶粉。这将是一项双盲研究。婴儿将每月接受一次检查，并将在七个场合通过足跟采血，以确定25-OHD和维生素D状态的功能指标。还将估计紫外线暴露。骨矿物质含量将测定一次（3月或4月，即，在冬天结束时）。其他终点将在多个场合进行测量。主要终点将是维生素D状态，即，25-OHD的血浆浓度，不足定义为浓度<15 ng/ml。我们假设，每天定期服用400 IU和600 IU维生素D可以可靠地预防维生素D缺乏症，但服用200 IU/天则不完全有效。维生素状态的功能指标将随着补充维生素D剂量的增加而增加。这项研究具有相当大的公共卫生重要性，因为预防维生素D缺乏症的重要性不仅在其严重的形式，佝偻病，而且在其温和的形式。