Jones G, Hogan D B, Yendt E, Hanley D A
Department of Biochemistry, Queen's University, Kingston, Ont.
CMAJ. 1996 Oct 1;155(7):955-61.
To review recent findings on the skeletal actions of vitamin D and to examine results of the latest clinical trials of vitamin D in the treatment of osteoporosis.
The vitamin D analog 1-alpha hydroxycholecalciferol (1 alpha-OH-D3); the vitamin D metabolite calcitriol.
Fracture and loss of bone mineral density in osteoporosis; increased bone mass, prevention of fractures and improved quality of life associated with vitamin D therapies.
Relevant laboratory and clinical studies and reports were examined. Greatest reliance was placed on recent large-scale, randomized, controlled trials; others were noted and their methods critiqued. Clinical practice in Japan was also considered.
Reducing fractures, increasing bone mineral density and minimizing side effects of treatment were given a high value.
BENEFITS, HARMS AND COSTS: Vitamin D maintains the dynamic nature of bone and so presumably helps to keep it healthy. Calcitriol and 1 alpha-OH-D3 may be effective in increasing bone mass and preventing fractures in osteoporosis. Calcitriol may be an alternative treatment in the prevention and management of corticosteroid-induced osteoporosis. Possible side effects of vitamin D analogs and metabolites are hypercalcemia, hypercalciuria, renal calcification and renal stones.
The use of 1 alpha-OH-D3 for the treatment of osteoporosis in Canada cannot be supported without larger and longer randomized, controlled clinical trials. Calcitriol appears to prevent vertebral fractures in patients with osteoporosis. More information is needed on its mechanism of action and efficacy in preventing hip fractures. Future studies should focus on comparisons with other effective therapies and on determining whether its effect on fractures is greater than that achieved through improved vitamin D nutrition. Patients taking calcitriol at dose levels required for antifracture effects should be monitored for serum and urine calcium response to the drug. Calcitriol should not be given to patients whose calcium intake is at current generally recommended levels. At present, prescription of calcitriol for the treatment of osteoporosis should be reserved for physicians with a special interest in the treatment of metabolic bone disease.
回顾维生素D骨骼作用的近期研究结果，并审视维生素D治疗骨质疏松症的最新临床试验结果。
维生素D类似物1-α羟胆钙化醇（1α-OH-D3）；维生素D代谢物骨化三醇。
骨质疏松症中的骨折和骨矿物质密度丧失；与维生素D疗法相关的骨量增加、骨折预防及生活质量改善。
审查了相关实验室和临床研究及报告。最倚重近期大规模随机对照试验；也提及其他试验并对其方法进行了批判。还考虑了日本的临床实践。
降低骨折发生率、增加骨矿物质密度并将治疗副作用降至最低被高度重视。
益处、危害及成本：维生素D维持骨骼的动态特性，因此大概有助于保持骨骼健康。骨化三醇和1α-OH-D3可能有效增加骨质疏松症患者的骨量并预防骨折。骨化三醇可能是预防和治疗糖皮质激素诱导的骨质疏松症的替代疗法。维生素D类似物和代谢物可能的副作用是高钙血症、高钙尿症、肾钙化和肾结石。
在没有更大规模、更长时间的随机对照临床试验的情况下，无法支持在加拿大使用1α-OH-D3治疗骨质疏松症。骨化三醇似乎可预防骨质疏松症患者的椎体骨折。关于其预防髋部骨折的作用机制和疗效，还需要更多信息。未来研究应侧重于与其他有效疗法的比较，以及确定其对骨折的影响是否大于通过改善维生素D营养所取得的效果。服用抗骨折作用所需剂量骨化三醇的患者，应监测其血清和尿钙对药物的反应。钙摄入量处于当前一般推荐水平的患者不应使用骨化三醇。目前，骨化三醇治疗骨质疏松症的处方应保留给对代谢性骨病治疗有特殊兴趣的医生。
