Gallagher J C
Bone Metabolism Unit, Creighton University Medical Center, 601 N. 30th Street (Suite 6718), Omaha, NE 68131, USA.
J Steroid Biochem Mol Biol. 2004 May;89-90(1-5):497-501. doi: 10.1016/j.jsbmb.2004.03.059.
There is an increase in the incidence of falls with aging and about 10% of falls lead to fractures. Nearly all hip fractures are due to falls and hip fractures are the most severe of the osteoporotic fractures because they lead to a 20% mortality rate and a loss of independent living in 50% of cases. Although there are multiple factors associated with falls, our interest is the role that vitamin D metabolism plays in the pathogenesis of falls. Recent clinical trials show that both vitamin D and the metabolite calcitriol reduce the number of falls by 30-40% in elderly subjects. This should also reduce the number of fractures. In European studies, the decrease in falls could be attributed to an improvement in the muscle weakness that often accompanies vitamin D deficiency. However, in the studies using calcitriol there was no vitamin D deficiency, so the mechanism of its efficacy is less clear. It could be due to increased muscle strength, an improvement in the neurological control of balance or both. Understanding these mechanisms would allow us to search for analogs of vitamin D that act more selectively on muscle and on the central nervous system.
随着年龄增长，跌倒的发生率会增加，约10%的跌倒会导致骨折。几乎所有髋部骨折都是由跌倒引起的，髋部骨折是骨质疏松性骨折中最严重的，因为它们导致20%的死亡率，且50%的病例会失去独立生活能力。尽管跌倒与多种因素相关，但我们感兴趣的是维生素D代谢在跌倒发病机制中所起的作用。最近的临床试验表明，维生素D及其代谢产物骨化三醇均可使老年受试者的跌倒次数减少30% - 40%。这也应会减少骨折的数量。在欧洲的研究中，跌倒次数的减少可归因于常伴随维生素D缺乏的肌肉无力状况得到改善。然而，在使用骨化三醇的研究中不存在维生素D缺乏的情况（因此），其疗效机制尚不太明确。这可能是由于肌肉力量增强、平衡的神经控制改善或两者兼而有之。了解这些机制将使我们能够寻找对肌肉和中枢神经系统具有更选择性作用的维生素D类似物。
