TREATMENT OF CALCIUM DEFICIENCY IN YOUNG WOMEN

科学家们普遍认为，峰值骨量直接关系到 在以后的生活中可能会出现骨折。 强壮的骨架 因此，在生命早期，应该有助于防止将来发生脆性骨折 几十年 虽然成年人的身高在18岁时达到， 整合可以持续几年，纵向， 我们实验室最近的一项观察性研究证实， 直到30岁才停止。 在这项研究中， 在健康的年轻女性中， 饮食中的蛋白质（蛋白质增加尿中钙的流失）。 （而1989年RDA的摄入量将产生膳食钙与蛋白质的比值， 26 mg/g的比例，20多岁女性受试者的主要摄入量 平均仅约12 mg/g）。 通过补钙， 在30岁之前很可能代表了一个更早抵消的独特机会， 自我限制膳食钙。 拟议的研究旨在审查这一机会， 这是我们早期观察性研究的后续。 我们建议一个为期三年， 一项双盲、安慰剂对照的随机临床试验， mg/d，以碳酸盐计，分次给药，随餐服用）或相同的外观 安慰剂 受试者将是年龄在19至24岁的不吸烟的年轻女性， 一般健康状况良好，其膳食钙与蛋白质的比例 (as通过7天食物日记评估）不超过12 mg/g。 目的是 通过排除更可能是钙的受试者来增加特异性- 吃饱了 在随机分配至治疗前，将对样本进行分层 根据基线全身骨矿物质含量（高于和低于 TBBM为1500 g/m高度）。 将入组238例受试者，以确保 160完结 TBBM和局部骨量的变化率 （脊柱，髋关节和前臂）将在整个研究期间确定每个受试者的 12至36个月（以避免重塑的影响） 短暂的，可能误导的早期治疗效果）。 拟议 这项研究将是第一个关于钙对骨骼影响的对照试验 设计为（i）避免重塑瞬态，（ii）考虑 蛋白质摄入的重要性，（iii）测试基线骨的影响 （iv）使用顺应性的客观量度（粪便钙密度）， 以及（v）检查这个重要年龄组的钙补充情况。

Scientists widely agree that peak bone mass relates directly to the likelihood of osteoporotic fractures later in life. A strong skeleton early in life should, then, help to prevent fragility fractures in future decades. Although full adult height is reached by age 18, skeletal consolidation can continue for several years, and a longitudinal, observational study from our laboratory recently confirmed that bone gain not stop until about age 30. In that study, the rate of gain in bone mass among healthy young women was directly related to the ratio of calcium-to- protein in their diets (protein increases loss of calcium in urine). (Whereas intakes at the 1989 RDAs would yield a dietary calcium-to-protein ratio of 26 mg/g, prevailing intakes among female subjects in their 20s average only about 12 mg/g.) Through calcium supplementation, the decade before age 30 may well represent a unique opportunity to offset earlier, self-imposed restriction of dietary calcium. The proposed study has been designed to examine that opportunity in a follow-up to our earlier observational study. We propose a three-year, double-blind, placebo-controlled randomized clinical trial of calcium (1500 mg/d as carbonate, in divided doses with meals) or an identical appearing placebo. The subjects will be non-smoking young women, aged 19 to 24 at entry and in good general health, whose dietary calcium-to-protein ratio (as assessed by 7-day food diary) does not exceed 12 mg/g. The purpose is to increase specificity by excluding subjects more likely to be calcium- replete. Before randomization to treatment, the sample will be stratified according to baseline total-body bone mineral content (above and below a TBBM of 1500 g/m height). 238 subjects will be enrolled to assure that at least 160 finish. Rates of change in TBBM and in regional bone mass (spine, hip, and forearm) will be determined for each subject over the period from 12 to 36 months (to avoid the influence of the remodeling transient, a potentially misleading early treatment effect). The proposed study will be the first controlled trial of calcium effects on bone designed to (i) avoid the remodeling transient, (ii) consider the importance of protein intake, (iii) test the influence of baseline bone mass, (iv) use an objective measure of compliance (fecal calcium density), and (v) examine calcium supplementation in this important age group.