CMAJ：低水平的维生素D或与家族长寿直接相关

2012年11月6日--近日，一项刊登于国际杂志Canadian Medical Association Journal上的研究报告指出，低浓度的维生素D或和长寿直接相关，这项研究的研究对象是90年代时期的中年人。研究者发现家族性的长寿和低水平的维生素D以及基因CYP2R1等位基因的低频率突变直接相关。

此前的研究揭示了低水平的维生素D和死亡、心脏疾病、糖尿病、癌症等疾病的风险增加相关，然而研究者并不知道是否低水平的维生素D是诱发这些疾病的原因抑或者是这些疾病导致了维生素D的水平降低。

本项研究中，研究者对380个白人家庭相关数据进行了调查分析，这些家庭中至少有两个年龄超过90岁的人，研究者随着季节和月份的变化，分别测定了研究对象的机体25（OH）维生素D的水平，并且进行分类。实验中研究者以性别、年龄、体重、时间、维生素摄入量以及肾脏功能作为控制，因为这些因素都可以影响维生素D的水平。

通过研究发现，90多岁人群的后代机体中维生素D的水平相比对照较低，而且这些后代在基因CYP2R1的遗传突变上也表现出较低的频率，基因CYP2R1的突变常导致个体表现出高水平的维生素D。

这项研究阐明了低水平维生素D和家族长寿之间的关联，研究者假设，长寿个体的后代机体中或许存在更多的老化抑制性蛋白质。当然研究者会进行深入研究来揭示低水平维生素D、遗传突变和家族长寿之间的具体关联。

与维生素D相关的拓展阅读：

• ARD：维生素D可通过增强线粒体功效使肌肉充满能量
• BMJ ：易感染患者服用维生素D或可避免呼吸道感染
• JCSM：维生素D缺乏易导致白天容易瞌睡
• Diabetologia：维生素D缺乏与1型糖尿病
• JBC：维生素D或可抑制糖尿病患者动脉的阻塞 更多信息请点击：有关维生素D更多资讯

Levels of 25-hydroxyvitamin D in familial longevity: the Leiden Longevity Study

Background: Low levels of 25(OH) vitamin D are associated with various age-related diseases and mortality, but causality has not been determined. We investigated vitamin D levels in the offspring of nonagenarians who had at least one nonagenarian sibling; these offspring have a lower prevalence of age-related diseases and a higher propensity to reach old age compared with their partners. Methods: We assessed anthropometric characteristics, 25(OH) vitamin D levels, parathyroid hormone levels, dietary vitamin D intake and single nucleotide polymorphisms (SNPs) associated with vitamin D levels. We included offspring (n = 1038) of nonagenarians who had at least one nonagenarian sibling, and the offsprings' partners (n = 461; controls) from the Leiden Longevity Study. We included age, sex, body mass index, month during which blood sampling was performed, dietary and supplemental vitamin D intake, and creatinine levels as possible confounding factors. Results: The offspring had significantly lower levels of vitamin D (64.3 nmol/L) compared with controls (68.4 nmol/L; p = 0.002), independent of possible confounding factors. There was no difference in the levels of parathyroid hormone between groups. Compared with controls, the offspring had a lower frequency of a genetic variant in the CYP2R1 gene (rs2060793) (p = 0.04). The difference in vitamin D levels between offspring and controls persisted over the 2 most prevalent genotypes of this SNP. Interpretation: Compared with controls, the offspring of nonagenarians who had at least one nonagenarian sibling had a reduced frequency of a common variant in the CYP2R1 gene, which predisposes people to high vitamin D levels; they also had lower levels of vitamin D that persisted over the 2 most prevalent genotypes. These results cast doubt on the causal nature of previously reported associations between low levels of vitamin D and age-related diseases and mortality.

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