Kinyamu H K, Gallagher J C, Rafferty K A, Balhorn K E
Bone Metabolism Unit, Creighton University School of Medicine, Omaha 68131, USA.
Am J Clin Nutr. 1998 Feb;67(2):342-8. doi: 10.1093/ajcn/67.2.342.
In this study, the effect of dietary calcium and vitamin D on serum parathyroid hormone and vitamin D metabolites was measured in 376 free-living women aged 65-77 y. Mean calcium intake in both groups was close to the recommended dietary allowance of 800 mg/d. Mean vitamin D intake in the 245 women not taking vitamin D supplements was 3.53 microg/d (141 IU/d), which is below the recommended dietary allowance of 5 microg/d (200 IU/d). To test the hypothesis that vitamin D is more important than calcium in reducing serum parathyroid hormone, the source of dietary calcium intake was subdivided into milk, which is fortified with vitamin D, and nonmilk sources. The serum parathyroid hormone concentration was inversely correlated with calcium intake derived from milk (r = -0.20, P < 0.01) but not from nonmilk sources (r = -0.06). Furthermore, serum calcidiol correlated with milk calcium intake (r = 0.35, P < 0.001) but not with nonmilk calcium intake (r = 0.10). Multivariate analysis showed a significant effect of season on serum calcidiol but not on serum parathyroid hormone. Serum parathyroid hormone was inversely correlated with serum calcidiol (r = -0.33, P < 0.001) and the regression predicted that mean serum parathyroid hormone would be reduced in the elderly to concentrations considered normal in the young when serum calcidiol is 122 nmol/L (49 ng/mL); this would require a much higher recommended dietary allowance for vitamin D than 5 microg/d (200 IU/d).
在本研究中，对376名年龄在65至77岁的自由生活女性测量了膳食钙和维生素D对血清甲状旁腺激素及维生素D代谢产物的影响。两组的平均钙摄入量均接近每日800毫克的膳食推荐摄入量。在245名未服用维生素D补充剂的女性中，平均维生素D摄入量为每日3.53微克（141国际单位），低于每日5微克（200国际单位）的膳食推荐摄入量。为了检验在降低血清甲状旁腺激素方面维生素D比钙更重要这一假设，将膳食钙摄入来源细分为添加了维生素D的牛奶及非牛奶来源。血清甲状旁腺激素浓度与来自牛奶的钙摄入量呈负相关（r = -0.20，P < 0.01），但与非牛奶来源的钙摄入量无关（r = -0.06）。此外，血清骨化二醇与牛奶钙摄入量相关（r = 0.35，P < 0.001），但与非牛奶钙摄入量无关（r = 0.10）。多变量分析显示季节对血清骨化二醇有显著影响，但对血清甲状旁腺激素无显著影响。血清甲状旁腺激素与血清骨化二醇呈负相关（r = -0.33，P < 0.001），回归分析预测，当血清骨化二醇为122纳摩尔/升（49纳克/毫升）时，老年人的血清甲状旁腺激素平均水平将降至年轻人的正常水平；这将需要比每日5微克（200国际单位）高得多的维生素D膳食推荐摄入量。
