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本帖最后由 久的永永 于 2014-1-14 07:50 编辑
一些中老年人会服用维生素D来预防骨质疏松。然而一项新研究发现，对于健康中老年人来说，这一预防效果并不明显。
英国新一期医学期刊《柳叶刀》刊登了新西兰科研人员的报告。研究者指出，他们综合分析了此前23项考察维生素D补充剂提高骨密度效果的研究报告。这些研究涉及4082名健康成年人，平均年龄为59岁。
分析结果显示，服用维D补充剂对于提高髋关节、脊柱和前臂的骨密度没有效果，对于全身骨骼整体骨密度的提高也基本无效，这种做法只能将股骨头中的骨密度平均提高0.8%，但这一幅度“没有临床意义”。
领导这项研究的奥克兰大学教授伊恩·里德说，这项研究表明，对于绝大多数健康人来说，为预防骨质疏松而服用维D补充剂没有必要，医生应该只给缺乏这种维生素的人群开补充剂，这样也可大幅节约医疗资源。（来源：中国科学报 刘石磊）
Effects of vitamin D supplements on bone mineral density: a systematic review and meta-analysis
The Lancet, Volume 383, Issue 9912, Pages 146 - 155, 11 January 2014
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doi:10.1016/S0140-6736(13)61647-5Cite or Link Using DOI
This article can be found in the following collections: Nutrition & Metabolism (Nutrition & metabolism-other)
Published Online: 11 October 2013
Summary
BackgroundFindings from recent meta-analyses of vitamin D supplementation without co-administration of calcium have not shown fracture prevention, possibly because of insufficient power or inappropriate doses, or because the intervention was not targeted to deficient populations. Despite these data, almost half of older adults (older than 50 years) continue to use these supplements. Bone mineral density can be used to detect biologically significant effects in much smaller cohorts. We investigated whether vitamin D supplementation affects bone mineral density.
MethodsWe searched Web of Science, Embase, and the Cochrane Database, from inception to July 8, 2012, for trials assessing the effects of vitamin D (D3 or D2, but not vitamin D metabolites) on bone mineral density. We included all randomised trials comparing interventions that differed only in vitamin D content, and which included adults (average age >20 years) without other metabolic bone diseases. We pooled data with a random effects meta-analysis with weighted mean differences and 95% CIs reported. To assess heterogeneity in results of individual studies, we used Cochran's Q statistic and the I2 statistic. The primary endpoint was the percentage change in bone mineral density from baseline.
FindingsOf 3930 citations identified by the search strategy, 23 studies (mean duration 23·5 months, comprising 4082 participants, 92% women, average age 59 years) met the inclusion criteria. 19 studies had mainly white populations. Mean baseline serum 25-hydroxyvitamin D concentration was less than 50 nmol/L in eight studies (n=1791). In ten studies (n=2294), individuals were given vitamin D doses less than 800 IU per day. Bone mineral density was measured at one to five sites (lumbar spine, femoral neck, total hip, trochanter, total body, or forearm) in each study, so 70 tests of statistical significance were done across the studies. There were six findings of significant benefit, two of significant detriment, and the rest were non-significant. Only one study showed benefit at more than one site. Results of our meta-analysis showed a small benefit at the femoral neck (weighted mean difference 0·8%, 95% CI 0·2—1·4) with heterogeneity among trials (I2=67%, p<0·00027). No effect at any other site was reported, including the total hip. We recorded a bias toward positive results at the femoral neck and total hip.
InterpretationContinuing widespread use of vitamin D for osteoporosis prevention in community-dwelling adults without specific risk factors for vitamin D deficiency seems to be inappropriate.
FundingHealth Research Council of New Zealand.
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发表于 2014-1-14 07:49
发表于 2014-1-14 08:18