Effect of Vitamin D and Calcium on Bone in Pediatric HIV

描述（由申请人提供）：我们最近观察到，与健康儿童相比，生活在美国东北部城市环境中的感染艾滋病毒的儿童骨量减少。由于儿童期和青春期是骨骼发育的关键时期，而且人们普遍认为，儿童期和青春期的最佳骨量增加可能会预防以后的骨质疏松症，这一观察结果对艾滋病毒感染儿童未来骨质疏松症和骨折的风险具有严重影响。虽然高活性抗逆转录病毒治疗（HAART）与成人骨骼脱矿的病因有关，但仍有可能是其他对骨骼健康重要的因素，如维生素D缺乏，可能导致或加剧艾滋病毒感染儿童的骨质流失。在这方面，我们发现一小群感染艾滋病毒的儿童中有50%缺乏或体内维生素D储存不足，通过血清25-羟基维生素D水平低于20 ng/ml来测量。该建议的中心假设是，在接受HAART治疗的艾滋病毒感染儿童中，维生素D缺乏和不足的患病率增加，并与这些儿童观察到的骨量减少有关。我们还假设补充维生素D和推荐的每日补钙量将改善这些患者的骨矿物质积累，就像在健康个体中一样。我们将在1中检验这些假设。一项比较艾滋病毒感染与健康儿童和青少年艾滋病毒感染、维生素D状况和骨量之间关系的横断面研究。一项为期两年的随机对照临床试验，在艾滋病毒感染的儿童和青少年中，将维生素D和钙补充剂对骨量累积的影响与安慰剂进行比较。

DESCRIPTION (provided by applicant): We have recently observed that HIV-infected children, living in an urban setting in the northeastern United States, have decreased bone mass compared to healthy children. As childhood and adolescence are the critical periods during life for skeletal development and, as it is widely recognized that optimal bone mass accretion during childhood and adolescence may prevent osteoporosis later in life, this observation has serious implications for future risk of osteoporosis and fractures in HIV-infected children. While Highly Active Antiretroviral Treatment (HAART) has been implicated in the etiology of the skeletal demineralization in adults, it remains possible that other factors important for skeletal health, such as vitamin D deficiency, could contribute to or exacerbate bone loss in HIV-infected children. In this regard, we have found that 50% of a small group of HIV-infected children have deficient or insufficient body stores of vitamin D, as measured by serum 25-hydroxyvitamin D levels below 20 ng/ml. The central hypotheses of this proposal are that the prevalence of vitamin D deficiency and insufficiency is increased in HIV-infected children receiving HAART and is related to the decreased bone mass observed in these children. We also hypothesize that supplementation with vitamin D and the recommended daily allowance of calcium will improve bone mineral accrual in these patients, as it does in healthy individuals. We will test these hypotheses in 1. a crosssectional study comparing HIV-infected and healthy children and adolescents with respect to relationships between HIV-infection, vitamin D status, and bone mass, and in 2. a two-year randomized, controlled clinical trial in which the effects of vitamin D and calcium supplementation on bone mass accrual are compared to placebo in HIV-infected children and adolescents.