Dose response to vitamin D supplementation in African Americans: results of a 4-arm, randomized, placebo-controlled trial.
Dose response to vitamin D supplementation in African Americans: results of a 4-arm, randomized, placebo-controlled trial.
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DOI：
10.3945/ajcn.113.067777
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发表时间：
2014-03
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影响因子：
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通讯作者：
K. Ng;Jamil B. Scott;B. Drake;A. Chan;B. Hollis;P. Chandler;G. Bennett;E. Giovannucci;Elizabeth Gonzalez-Suarez;J. Meyerhardt;K. Emmons;C. Fuchs
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文献类型：
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作者：
K. Ng;Jamil B. Scott;B. Drake;A. Chan;B. Hollis;P. Chandler;G. Bennett;E. Giovannucci;Elizabeth Gonzalez-Suarez;J. Meyerhardt;K. Emmons;C. Fuchs
相关研究表明，非洲裔美国人中较低的循环25-羟基维生素D [25（OH）D]可能是该人群心血管疾病和癌症发病率较高的部分原因。尽管如此，在非裔美国人中，维生素D补充和25（OH）D浓度之间的关系仍然不确定。目的我们的主要目的是确定维生素D和血浆25（OH）D之间的剂量-反应关系。研究设计：在2007年至2010年的3个冬季期间，在马萨诸塞州波士顿共招募了328名非洲裔美国人，随机分配接受安慰剂或1000、2000或4000 IU维生素D治疗3个月。受试者完成了社会人口统计学和饮食问卷调查，并在基线和3个月和6个月抽取血浆样本。结果：随机分配接受安慰剂或1000、2000或4000 IU/d的受试者，基线时血浆25（OH）D浓度中位数分别为15.1、16.2、13.9和15.7 ng/mL（P = 0.63）。3个月时，补充组之间的中位血浆25（OH）D浓度差异显著，分别为13.7、29.7、34.8和45.9 ng/mL（P < 0.001）。在≥ 97.5%的受试者中，估计需要1640 IU维生素D/d才能将血浆25（OH）D浓度升高至≥ 20 ng/mL，而在≥ 80%的受试者中，需要4000 IU/d的剂量才能达到≥ 33 ng/mL的浓度。在一部分参与者中没有观察到显著的高钙血症。结论在非裔美国人中，估计需要1640 IU维生素D/d才能达到医学研究所推荐的血浆25（OH）D浓度，而需要4000 IU/d才能达到预期的浓度，以降低癌症和心血管疾病的风险在前瞻性观察性研究中。这些结果可能有助于为未来的疾病预防试验提供信息。
BACKGROUND Association studies have suggested that lower circulating 25-hydroxyvitamin D [25(OH)D] in African Americans may partially underlie higher rates of cardiovascular disease and cancer in this population. Nonetheless, the relation between vitamin D supplementation and 25(OH)D concentrations in African Americans remains undefined. OBJECTIVE Our primary objective was to determine the dose-response relation between vitamin D and plasma 25(OH)D. DESIGN A total of 328 African Americans in Boston, MA, were enrolled over 3 winters from 2007 to 2010 and randomly assigned to receive a placebo or 1000, 2000, or 4000 IU vitamin D₃/d for 3 mo. Subjects completed sociodemographic and dietary questionnaires, and plasma samples were drawn at baseline and 3 and 6 mo. RESULTS Median plasma 25(OH)D concentrations at baseline were 15.1, 16.2, 13.9, and 15.7 ng/mL for subjects randomly assigned to receive the placebo or 1000, 2000, or 4000 IU/d, respectively (P = 0.63). The median plasma 25(OH)D concentration at 3 mo differed significantly between supplementation arms at 13.7, 29.7, 34.8, and 45.9 ng/mL, respectively (P < 0.001). An estimated 1640 IU vitamin D₃/d was needed to raise the plasma 25(OH)D concentration to ≥ 20 ng/mL in ≥ 97.5% of participants, whereas a dose of 4000 IU/d was needed to achieve concentrations ≥ 33 ng/mL in ≥ 80% of subjects. No significant hypercalcemia was seen in a subset of participants. CONCLUSIONS Within African Americans, an estimated 1640 IU vitamin D₃/d was required to achieve concentrations of plasma 25(OH)D recommended by the Institute of Medicine, whereas 4000 IU/d was needed to reach concentrations predicted to reduce cancer and cardiovascular disease risk in prospective observational studies. These results may be helpful for informing future trials of disease prevention.