Does vitamin D supplementation reduce cognitive decline?

澳大利亚的人口正在迅速老龄化，与年龄有关的疾病的频率也在迅速上升。痴呆症是老年人最常见的精神健康障碍之一，也是澳大利亚因残疾而损失多年生命的主要原因之一。老年轻度认知障碍（MCI）被认为是预测未来认知能力下降的重要临床状态。越来越多的证据表明，针对潜在的可改变的危险因素可以延迟痴呆症的发病。维生素D对健康的骨骼和肌肉功能很重要，但现在也被认为对健康的大脑功能很重要。这项随机安慰剂对照临床试验的目的是调查维生素D水平低的MCI老年人补充维生素D 18个月是否有助于减少认知能力下降。110名患有轻度认知障碍的老年人将被随机（像抛硬币一样随机）分为积极治疗组和安慰剂组。在6个月、12个月和18个月时比较他们的认知（如记忆）表现、生活质量和功能水平。如果我们的假设得到证实，补充维生素D可能被证明是一种简单、有效和廉价的延缓痴呆症风险人群认知能力下降的方法。这可能会导致澳大利亚重新考虑目前的阳光照射政策，并更广泛地使用食品强化和补充。

Australia's population is ageing rapidly and so is the frequency of age-related disorders. Dementia is one of the most frequent mental health disorders of older people and one of the leading causes of years of life lost due to disability in Australia. Mild Cognitive Impairment (MCI) in old age is considered an important clinical state predictive of future cognitive decline. There is increasing evidence that the onset of dementia can be delayed with targeting potentially modifiable risk factors. Vitamin D is important for healthy bones and muscle function, but is now also discussed as being important for healthy brain function. The purpose of this randomised placebo-controlled clinical trial is to investigate whether supplementation with vitamin D for 18 months in older adults with MCI who have low vitamin D levels, can help to reduce cognitive decline. 110 older adults with MCI will be randomised (by chance, like the flip of a coin) to either active treatment or placebo. Their cognition (such as memory) performance, quality of life and functional level will be compared at 6, 12, and 18 months. If our hypothesis is confirmed, vitamin D supplementation might prove to be a simple, effective and inexpensive way of delaying cognitive decline in people at risk for dementia. This could lead to the reconsideration of current sun exposure policies in Australia and the more widespread use of food fortification and supplementation.