TORONTO (EGMN) – A daily vitamin D dose of at least 792 IU was linked with significantly reduced rates of nonvertebral fractures and hip fractures in a meta-analysis of data from 11 randomized, controlled trials.

But the benefit from vitamin D appeared blunted when combined with a higher calcium dose, or when patients received vitamin D once yearly, Dr. Heike A. Bischoff-Ferrari reported.

In the meta-analysis, patients in the highest quartile for daily vitamin D intake, 792-2000 IU, had a statistically significant 14% reduced rate of any nonvertebral fracture, and a significant 30% reduced rate of hip fractures, in an analysis that adjusted for age, gender, and type of dwelling, said Dr. Bischoff-Ferrari, a rheumatologist at the University of Zurich.

Her meta-analysis pooled individual participant data from 12 double-blind, randomized, controlled trials that examined the impact of vitamin D supplements on fracture rate in people aged 65 years or older published through June 2010, and for which she could obtain individual participant data. The primary analysis focused on the 11 studies of the 12 in which participants received the supplement at least monthly, with 31,022 people enrolled. The twelfth study tested once annual dosing, and the researchers included those data in a separate analysis. The participants’ average age was 76 years, and about 90% were women.

The analysis divided the study subjects into the control group, with more than 15,000 people, and then into quartiles of their received amount of vitamin D, including both their study-treatment dose and any additional vitamin D intake. The analysis also took into account adherence to treatment. Each vitamin D quartile contained nearly 4,000 people, with a daily dose range of 792-2,000 mg forming the top quartile. Only the top quartile of vitamin intake linked with statistically significant differences, compared with the controls, for any nonvertebral fracture and for hip fracture.

Adding the data from the one trial that tested annual vitamin D treatment to the meta-analysis eliminated the statistically significant effect on fracture rates, suggesting that yearly administration of vitamin D produces a different effect than daily, weekly, or monthly treatment.

An additional analysis that looked at the interaction of calcium supplements along with vitamin D showed that with a daily calcium dose below 1,000 mg/day a high-dose vitamin D supplement (792-2,000 mg/day) linked with a statistically significant reduction in nonvertebral fractures, but when the daily calcium supplement delivered 1,000 mg or more, this amount of vitamin D did not associate with any significant change in fracture rate, suggesting an adverse effect from higher calcium intake.

Dr. Bischoff-Ferrari said that she had no disclosures.

Copyright (c) 2010 Elsevier Global Medical News. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

多伦多(EGMN)——对11项随机对照临床试验进行荟萃分析结果显示，每天服用维生素D至少792  U，能够显著降低非椎骨骨折和髋骨骨折的发生率。

 

苏黎世大学风湿病学专家Heike A. Bischoff-Ferrari博士进行的荟萃分析中，汇总了12项双盲、随机对照临床试验中的所有受试者，这些临床试验结果均在2010年6月发表，研究内容为维生素D补剂对年龄≥65岁人群骨折发生率的影响。研究者主要分析了其中11项临床试验的结果，在这些临床试验中，31,022名受试者至少每月服用1次补剂。在第12项临床试验中，受试者每年服用1次补剂，研究者单独分析了这些数据。

 

受试者平均年龄76岁，约90%为女性。研究者将受试者分为对照组(15,000余人)，然后按照服用维生素D剂量的四分位数分为四组，包括研究的治疗量和任何额外的维生素D摄取量。每个维生素D治疗组将近4,000人，最高剂量组每日服药792~2,000 U。

 

对年龄、性别和居住方式进行调整后，每日服用维生素D最高剂量组792~2000 U的患者中，非椎骨骨折的发生率显著降低14%，髋骨骨折显著降低30%，同对照组相比，差异有统计学意义。而在其他剂量组，差异无统计学意义。每年服用1次维生素D的试验结果显示，其对骨折发生率的影响无统计学意义，提示每年服用1次维生素D同每天、每周或每月服用效果不同。

 

另外一项分析，研究了钙补剂和维生素D的相互作用，结果显示每日服用低于1,000 mg的钙剂，并且每日服用高剂量维生素D补剂(792~2,000 U)，非椎骨骨折的发生率显著降低，但当每日服用≥1,000 mg的钙剂，该高剂量的维生素D将不会显著降低骨折的发生率，提示高剂量钙剂会起到不良作用。

 

研究者无利益冲突声明。

 

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