24,25-DIHYDROXYVITAMIN D: MARKER OF SALT SENSITIVITY

24,25-二羟基维生素 D：盐敏感性标志物

• 批准号: 6287708
• 负责人: Connie Marie Weaver
• 金额: $ 16.55万
• 依托单位: PURDUE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-07-01 至 2003-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6287708
• 关键词: African American; adolescence (12-20); aldosterone; biomarker; bone density; bone imaging /visualization /scanning; bone metabolism; calcium metabolism; caucasian American; dietary calcium; electrolyte balance; female; gastrointestinal nutrient absorption; hormone regulation /control mechanism; human subject; magnesium ion; nutrition related tag; potassium ion; questionnaires; racial /ethnic difference; renal tubular transport; salt intake; statistics /biometry; urinalysis

DESCRIPTION (Adapted from Applicant s Description): Optimal calcium retention is a prerequisite for building maximal peak bone mass within the genetic potential, a key to reducing risk of osteoporosis later in life. The investigators have determined that maximal calcium retention averages 423 mg/day during the period of rapid skeletal accretion in white adolescent girls at a mean dietary calcium intake of 1300 mg/day. Urinary calcium explains more than 50% of the variance in calcium retention. However, urinary sodium (i.e. sodium intake) is a major determinant of urinary calcium excretion, and the effect of sodium intake on maximal calcium retention is not known. Nor is its effect known in black adolescents who have higher bone density and lower calcium excretion than white adolescents. The primary aim of this proposal is to test the hypothesis that high dietary sodium increases the calcium intakes required for optimal calcium retention in both black and white adolescent girls. Calcium retention will be measured at two levels of dietary sodium in a randomized crossover design on one of two levels of dietary calcium intake in black and white adolescent girls during three week metabolic periods. The investigators hypothesize that the mechanisms which regulate sodium reabsorption in the renal tubules also regulate calcium retention. Increased incidence of hypertension in blacks compared to whites has been attributed to increased sodium retention. Sodium intake induced changes in calcium and sodium retention in both races will be related to changes in sodium handling (plasma renin activity, serum aldosterone, and salt sensitivity) and calcium-regulating hormones, biomarkers of bone turnover, and bone mass. These studies are expected to define optimal calcium and sodium intakes for optimizing peak bone mass in both white and black adolescents. Furthermore, they should provide an explanation for the paradox that blacks can build higher bone density, have a lower rate of bone turnover, and excrete less urinary calcium on the same sodium loads compared to whites.

描述（改编自申请人的描述）：最佳钙 保留是建立最大峰值骨质量的先决条件 遗传潜力，这是降低后来生活中骨质疏松症风险的关键。 研究人员已经确定最大钙保留平均 在白色青少年快速骨骼积聚期间423毫克/天 女孩的平均饮食钙摄入量为1300 mg/天。 尿钙 解释了钙保留方差的50％以上。 然而， 泌尿钠（即钠摄入量）是尿的主要决定因素 钙排泄，以及钠摄入量对最大钙的影响 保留尚不清楚。 在黑人青少年中，其影响也不是 比白人青少年具有更高的骨密度和更低的钙排泄。 该提议的主要目的是检验高饮食的假设 钠增加了最佳钙保留所需的钙摄入量 黑白青春期女孩。 钙保留将是 在随机跨界设计中以两个级别的饮食钠的测量 黑白青少年的两个饮食钙摄入量的两个级别之一 女孩在三周的代谢期间。 调查人员假设 调节肾小管中钠重吸收的机制 还调节钙保留。 高血压发病率增加 与白人相比，黑人归因于钠的保留率增加。 钠摄入量诱导了两个种族的钙和钠保留变化 将与钠处理的变化有关（血浆肾素活性，血清 醛固酮和盐敏感性）和钙调节激素， 骨转换的生物标志物和骨骼质量。 预计这些研究将定义最佳钙和钠摄入量 优化白人和黑色青少年的峰值骨量。 此外， 他们应该为黑人可以建立的悖论提供解释 较高的骨密度，骨转换率较低，排泄物较小 与白人相比，相同钠负荷上的尿钙。