Pop L C, Sukumar D, Schneider S H, Schlussel Y, Stahl T, Gordon C, Wang X, Papathomas T V, Shapses S A
Department of Nutritional Sciences, Rutgers University, 96 Lipman Drive, New Brunswick, NJ, 08901-8525, USA.
Department of Nutritional Sciences, Drexel University, Philadelphia, PA, USA.
Osteoporos Int. 2017 Jan;28(1):377-388. doi: 10.1007/s00198-016-3735-z. Epub 2016 Aug 17.
The effects of higher than recommended vitamin D doses on bone mineral density (BMD) and quality are not known. In this study, higher intakes, in postmenopausal women undergoing weight control over 1 year, had no effect on areal or volumetric BMD but prevented the deterioration in cortical bone geometry.
Studies examining how bone responds to a standard dose of vitamin D supplementation have been inconsistent. In addition, the effects of higher doses on BMD and quality are not known. Postmenopausal women undergoing weight control to improve health outcomes are particularly at risk for bone loss and might benefit from supplemental vitamin D intake above the recommended allowance.
This 1-year-long, randomized, double-blind controlled study addresses whether vitamin D supplementation, in healthy overweight/obese older women, affects BMD and bone structural parameters. In addition, bone turnover and serum total, free, and bioavailable 25-hydroxyvitamin D (25OHD) responses to one of three daily levels of vitamin D (600, 2000, 4000 IU) with 1.2 Ca g/day during weight control were examined.
Fifty-eight women (age, 58 ± 6 years; body mass index, 30.2 ± 3.8 kg/m, serum 25OHD, 27.3 ± 4.4 ng/mL) were randomized to treatment. After 1 year, serum 25OHD concentrations increased to 26.5 ± 4.4, 35.9 ± 4.5, and 41.5 ± 6.9 ng/mL, in groups 600, 2000, and 4000 IU, respectively, and differed between groups (p < 0.01). Weight change was similar between groups (-3.0 ± 4.1 %). Cortical (Ct) thickness of the tibia changed by -1.5 ± 5.1 %, +0.6 ± 3.2 %, and +2.0 ± 4.5 % in groups 600, 2000, and 4000 IU, respectively, and each group was significantly different from each other (p < 0.05).
The decline in Ct thickness was prevented with higher vitamin D supplementation, but there were no other significant changes due to treatment over 1 year. Whether these findings translate to changes in biomechanical properties leading to reduced fracture risk should be addressed in future studies.
高于推荐剂量的维生素D对骨矿物质密度（BMD）和骨质的影响尚不清楚。在本研究中，对绝经后女性进行为期1年的体重控制，较高的维生素D摄入量对面积骨密度或体积骨密度没有影响，但可防止皮质骨几何结构的恶化。
研究骨对标准剂量维生素D补充剂反应的研究结果并不一致。此外，高剂量对骨密度和骨质的影响尚不清楚。为改善健康状况而进行体重控制的绝经后女性尤其有骨质流失的风险，补充高于推荐剂量的维生素D可能有益。
这项为期1年的随机双盲对照研究探讨了健康超重/肥胖老年女性补充维生素D是否会影响骨密度和骨结构参数。此外，还研究了在体重控制期间，骨转换以及血清总25-羟基维生素D（25OHD）、游离25OHD和生物可利用25OHD对三种每日维生素D水平（600、2000、4000国际单位）之一与每日1.2克钙的反应。
58名女性（年龄58±6岁；体重指数30.2±3.8kg/m²；血清25OHD 27.3±4.4ng/mL）被随机分组接受治疗。1年后，600、2000和4000国际单位组的血清25OHD浓度分别升至26.5±4.4、35.9±4.5和41.5±6.9ng/mL，组间存在差异（p<0.01）。各组间体重变化相似（-3.0±4.1%）。600、2000和4000国际单位组胫骨皮质（Ct）厚度分别变化-1.5±5.1%、+0.6±3.2%和+2.0±4.5%，每组之间差异显著（p<0.05）。
补充较高剂量的维生素D可防止Ct厚度下降，但1年的治疗未导致其他显著变化。这些发现是否会转化为生物力学性能的改变从而降低骨折风险，有待未来研究解决。
