Maalouf Joyce, Nabulsi Mona, Vieth Reinhold, Kimball Samantha, El-Rassi Rola, Mahfoud Ziyad, El-Hajj Fuleihan Ghada
Calcium Metabolism and Osteoporosis Program, American University of Beirut-Medical Center, Bliss Street, Beirut, Lebanon.
J Clin Endocrinol Metab. 2008 Jul;93(7):2693-701. doi: 10.1210/jc.2007-2530. Epub 2008 Apr 29.
Hypovitaminosis D is prevalent in youth worldwide, but the safety of vitamin D at doses exceeding 200 IU/d is unknown in this age group. We assessed the safety of high doses of vitamin D(3) administered to apparently healthy schoolchildren.
To assess short-term safety, 25 subjects randomly received placebo or vitamin D(3) at doses of 14,000 IU/wk for 8 wk. To assess long-term safety, 340 subjects randomly received placebo, vitamin D(3) as 1,400 IU/wk or 14,000 IU/wk for 1 yr. Biochemical variables were monitored at 0, 2, 4, 6, and 8 wk and 8 wk off therapy in the short-term study and at 0, 6, and 12 months in the long-term study.
In both the short- and long-term studies, mean serum calcium and 1,25-hydroxyvitamin levels did not change in any group. In the short-term study, mean 25-hydroxyvitamin concentrations increased from 44 (+/- 11) to 54 (+/- 19) ng/ml in the treated groups (P = 0.033). In the long-term study, mean 25-hydroxyvitamin D levels increased from 15 +/- 8 to 19 +/- 7 ng/ml (P < 0.0001) in subjects receiving 1,400 IU/wk and from 15 +/- 7 to 36 +/- 22 ng/ml (P < 0.0001) in the group receiving 14,000 IU/wk. No subject developed vitamin D intoxication.
Vitamin D(3) at doses equivalent to 2000 IU/d for 1 yr is safe in adolescents and results in desirable vitamin D levels.
维生素D缺乏在全球青少年中普遍存在，但该年龄组中每日剂量超过200国际单位的维生素D安全性尚不清楚。我们评估了给予看似健康的学童高剂量维生素D(3)的安全性。
为评估短期安全性，25名受试者随机接受安慰剂或每周14,000国际单位的维生素D(3)，共8周。为评估长期安全性，340名受试者随机接受安慰剂、每周1,400国际单位或14,000国际单位的维生素D(3)，共1年。在短期研究中，于0、2、4、6和8周以及停药8周时监测生化指标；在长期研究中，于0、6和12个月时监测。
在短期和长期研究中，任何组的血清钙和1,25-羟维生素水平均值均未改变。短期研究中，治疗组的25-羟维生素浓度均值从44（±11）ng/ml增至54（±19）ng/ml（P = 0.033）。长期研究中，接受每周1,400国际单位的受试者25-羟维生素D水平均值从15±8增至19±7 ng/ml（P < 0.0001），接受每周14,000国际单位的组从15±7增至36±22 ng/ml（P < 0.0001）。无受试者发生维生素D中毒。
相当于每日2000国际单位的维生素D(3)剂量服用1年对青少年是安全的，并能达到理想的维生素D水平。
