Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, PO Box 14155-6117, Tehran, Iran.
Eur J Endocrinol. 2013 Oct 1;169(5):597-604. doi: 10.1530/EJE-13-0068. Print 2013 Nov.
Guidelines on the need for dose adaptation of vitamin D3 supplementation according to baseline serum 25(OH)D are inconclusive. The effects of increasing doses of vitamin D3 at lower baseline serum 25(OH)D values on the serum 25(OH)D after 4.2 and 11 months were determined in an observational study.
A prospective observational study.
Out of 1481 consecutive women and men with a recent clinical fracture, 707 had a baseline 25(OH)D level <50 nmol/l and were supplemented with increasing doses of vitamin D3 (400, 800, 1700, and ≥3500 IU/day) according to the lower baseline 25(OH)D. Final analysis was restricted to the 221 participants who had full follow-up data available for 11 months.
Serum 25(OH)D ≥50 nmol/l was achieved in 57-76% of patients after 4.2 months and in 73-79% after 11 months. These percentages were similar for all doses (P=0.06 and P=0.91 respectively). The mean achieved 25(OH)D was similar for all dose groups (56.1-64.0 nmol/l after 4.2 months and 60.2-76.3 nmol/l after 11 months). With multivariate analysis, the increase in 25(OH)D (17±32.0 after 4.2 months and 24.3±34.0 nmol/l after 11 months) was dependent on the baseline 25(OH)D (P<0.001), not on supplementation dose, season, age, BMI, or gender.
The increase in serum 25(OH)D was significantly larger with higher vitamin D3 supplementation doses. However, this dose-effect response was mainly explained by the baseline 25(OH)D, not the supplementation dose, with a greater magnitude of response at lower baseline 25(OH)D concentrations. In 21-27% of patients, serum 25(OH)D3 levels did not reach 50 nmol/l after 11 months, at any dose. Further studies are needed to identify possible causes of suboptimal response such as non-compliance, undiagnosed malabsorption syndromes, or variability in cholecalciferol content of the vitamin D supplements.
根据基线血清 25（OH）D 水平，制定维生素 D3 补充剂量调整指南的必要性尚不清楚。本研究通过观察性研究，旨在评估在基线血清 25（OH）D 水平较低的情况下，增加维生素 D3 剂量对 4.2 个月和 11 个月后血清 25（OH）D 的影响。
前瞻性观察性研究。
对最近有临床骨折的 1481 名女性和男性患者进行研究，其中 707 名患者基线 25（OH）D 水平<50 nmol/l，根据较低的基线 25（OH）D 水平，给予不同剂量的维生素 D3（400、800、1700 和≥3500 IU/天）进行补充。最终分析仅限于 221 名患者，他们在 11 个月内有完整的随访数据。
4.2 个月后，57-76%的患者血清 25（OH）D≥50 nmol/l，11 个月后，73-79%的患者血清 25（OH）D≥50 nmol/l。所有剂量组的百分比相似（P=0.06 和 P=0.91）。所有剂量组的平均 25（OH）D 水平相似（4.2 个月后为 56.1-64.0 nmol/l，11 个月后为 60.2-76.3 nmol/l）。多变量分析显示，25（OH）D 的增加（4.2 个月后增加 17±32.0 nmol/l，11 个月后增加 24.3±34.0 nmol/l）与基线 25（OH）D 相关（P<0.001），与补充剂量、季节、年龄、BMI 或性别无关。
血清 25（OH）D 的增加与较高剂量的维生素 D3 补充显著相关。然而，这种剂量效应反应主要由基线 25（OH）D 决定，而不是补充剂量，在较低的基线 25（OH）D 浓度下，反应幅度更大。在任何剂量下，仍有 21-27%的患者在 11 个月后血清 25（OH）D3 水平未达到 50 nmol/l。需要进一步研究以确定非依从性、未诊断的吸收不良综合征或维生素 D 补充剂中胆钙化醇含量的差异等可能导致治疗反应不理想的原因。
