英国埃克塞特大学研究团队首次确立维生素D缺乏和认知问题间清晰的关联。这一由David J. Llewellyn博士领导的研究发现发表在有声望的《内科学档案》杂志上,它是一个国际性合作的结果。
维生素D是一种脂溶性的维生素,它存在于诸如多油脂的鱼等几种食物中。它也可作为一种食品补充剂。维生素D主要是在皮肤接触日光中的紫外光线后产生的。然而,随着年龄变老,人的皮肤产生维生素D的效率降低。大多数的在欧洲和美国的老年人的维生素D的水平都不足。人们对维生素D的兴趣最近有所增强,因为研究人员发现,它在范围广泛的诸如癌症、心脏病及中风等与衰老有关的疾病中可能扮演着一个重要的角色。
该项研究中包括了在1998年至2006年期间参加了InCHIANTI研究的生活在意大利的850多名老年人(他们的年龄为65岁或以上)。每一位参与者的认知功能都用标准的测定方法进行了评估,这些方法有一般认知能力(MMSE)、心智灵活性及心智速度。与具有健康维生素D水平的参与者相比,那些维生素D严重缺乏者感受到显著的总体认知水平衰退的可能性会增加60%,感受到新发心智灵活性问题的可能性会增加31%。
据估计,全世界有10亿人有维生素D不足的问题,所以这是一个非常令人担忧的原因。很少有食物含有维生素D,在纬度偏北地区的一年中,在大多数的时间内无法靠阳光来合成维生素D,而且随着年龄的衰老,皮肤产生维生素D的效率也有所降低。认知功能的衰退及痴呆在老年人中也很常见,尽管人们对其基础原因大体上仍然不清楚,而目前的用于预防和治疗的选项也很有限。维生素D因此是一种十分有希望的预防痴呆症的治疗标靶,特别是它作为补充剂价格便宜、安全而且它已经显示了具有减少跌倒、骨折和死亡风险的功效。
| 天下美食 麻辣烫配方 珍珠奶茶 四季食补 凉茶配方 |
|
|
Arch Intern Med. 2010;170(13):1135-1141. doi:10.1001/archinternmed.2010.173
Vitamin D and Risk of Cognitive Decline in Elderly Persons
David J. Llewellyn, PhD; Iain A. Lang, PhD; Kenneth M. Langa, MD, PhD; Graciela Muniz-Terrera, PhD; Caroline L. Phillips, MS; Antonio Cherubini, MD; Luigi Ferrucci, MD, PhD; David Melzer, PhD
Background To our knowledge, no prospective study has examined the association between vitamin D and cognitive decline or dementia.
Methods We determined whether low levels of serum 25-hydroxyvitamin D (25[OH]D) were associated with an increased risk of substantial cognitive decline in the InCHIANTI population–based study conducted in Italy between 1998 and 2006 with follow-up assessments every 3 years. A total of 858 adults 65 years or older completed interviews, cognitive assessments, and medical examinations and provided blood samples. Cognitive decline was assessed using the Mini-Mental State Examination (MMSE), and substantial decline was defined as 3 or more points. The Trail-Making Tests A and B were also used, and substantial decline was defined as the worst 10% of the distribution of decline or as discontinued testing.
Results The multivariate adjusted relative risk (95% confidence interval [CI]) of substantial cognitive decline on the MMSE in participants who were severely serum 25(OH)D deficient (levels <25 nmol/L) in comparison with those with sufficient levels of 25(OH)D (75 nmol/L) was 1.60 (95% CI, 1.19-2.00). Multivariate adjusted random-effects models demonstrated that the scores of participants who were severely 25(OH)D deficient declined by an additional 0.3 MMSE points per year more than those with sufficient levels of 25(OH)D. The relative risk for substantial decline on Trail-Making Test B was 1.31 (95% CI, 1.03-1.51) among those who were severely 25(OH)D deficient compared with those with sufficient levels of 25(OH)D. No significant association was observed for Trail-Making Test A.
Conclusion Low levels of vitamin D were associated with substantial cognitive decline in the elderly population studied over a 6-year period, which raises important new possibilities for treatment and prevention.
