TREATMENT OF CALCIUM DEFICIENCY IN YOUNG WOMEN

科学家们普遍认为，峰值骨量与 晚年骨质疏松性骨折的可能性。结实的骨骼 那么，生命早期应该有助于防止未来的脆性骨折 几十年。虽然成年人的身高在18岁时就会完全达到，但骨骼 整合可以持续几年，纵向的， 我们实验室最近的观察研究证实，骨量增加 一直到30岁左右才停止。在那项研究中，骨量的增加率 在健康的年轻女性中，与钙与钙的比率直接相关 他们饮食中的蛋白质(蛋白质会增加尿钙的损失)。 (而RDA的摄入量会产生膳食中的钙与蛋白质之比 26毫克/克，20多岁女性受试者的普遍摄入量 平均只有12毫克/克。)通过补钙，十年 在30岁之前可能代表着一个独特的机会来更早地抵消， 自我限制饮食中的钙。 拟议的研究旨在通过一项 我们早期观察性研究的后续行动。我们提议一项为期三年的 钙的双盲、安慰剂对照随机临床试验(1500 Mg/d，碳酸盐，随餐分次服用)或出现相同的 安慰剂。受试者将是不吸烟的年轻女性，年龄在19岁至24岁之间 进入并总体健康状况良好，其饮食中钙与蛋白质的比例 (根据7天饮食日记评估)不超过12毫克/克。其目的是 通过排除更有可能是钙的受试者来增加特异性- 满满的。在随机分组进行治疗之前，样本将被分层 根据基线全身骨矿含量(高于和低于a 1500g/m高度的TBBM)。将招收238名科目，以确保在 至少完成160次。全身骨量和局部骨量的变化率 (脊椎、臀部和前臂)将在 为期12至36个月(以避免改建的影响 暂时性的，潜在误导性的早期治疗效果)。建议数 这项研究将是钙对骨骼影响的第一次对照试验 旨在(I)避免改建瞬变，(Ii)考虑 蛋白质摄入量的重要性，(Iii)测试基线骨骼的影响 质量，(4)使用符合情况的客观衡量标准(粪便钙密度)， 以及(V)检查这一重要年龄段的补钙情况。

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.