Department of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China; Centre for Genomic Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China; Department of Pharmacology and Pharmacy, The University of Hong Kong, Pokfulam, Hong Kong, China; Research Centre of Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong, Pokfulam, Hong Kong, China.
Institute for Aging Research, Hebrew SeniorLife, 1200 Centre St., Boston, MA 02131, USA; Harvard Medical School, Boston, MA, USA.
Clin Nutr. 2015 Apr;34(2):235-40. doi: 10.1016/j.clnu.2014.03.011. Epub 2014 Apr 2.
BACKGROUND & AIMS: Cardiovascular disease (CVD) is the leading cause of death in patients with chronic kidney disease (CKD), partly due to increased vascular calcification. Vitamin K plays a role in preventing vascular calcification in CKD yet the relationship between vitamin K intake and mortality in CKD patients remains unclear.
This observational cohort study included 3401 participants with CKD from the Third National Health and Nutrition Examination Survey. Vitamin K intake was estimated from 24-h dietary recalls (1988-94). Mortality was determined from the National Death Index records through 2006. Cox-proportional hazards regression was used to estimate Hazard Ratios (HR) by comparing those with adequate intake of vitamin K to those with low intake, adjusting for advanced CKD covariates. For sensitivity analysis, these associations were also examined among those with different renal status.
During a median follow-up of 13.3 years (37,408 person-years), 1815 and 876 participants died from all-cause and CVD causes, respectively. 72% of the participants had vitamin K intake lower than the recommended adequate intake. Participants with vitamin K intake higher than recommended adequate intake for vitamin K were associated with lower risk of all-cause (HR = 0.85; 95%: 0.72-1; P = 0.047) and CVD mortality (HR = 0.78; 95%: 0.64-95; P = 0.016). Sensitivity analyses in subgroups with advanced CKD revealed similar findings.
This observational study suggests that adequate intake of vitamin K may be associated with reduced all-cause and CVD mortality in CKD patients. However, vitamin K may be a marker of a healthy diet; therefore clinical trials may help in clarifying the effect of vitamin K independent of a healthy diet.
心血管疾病（CVD）是慢性肾脏病（CKD）患者死亡的主要原因，部分原因是血管钙化增加。维生素 K 在预防 CKD 中的血管钙化中起作用，但维生素 K 摄入量与 CKD 患者死亡率之间的关系尚不清楚。
本观察性队列研究纳入了第三次全国健康和营养调查中的 3401 名 CKD 患者。通过 24 小时膳食回顾（1988-94 年）来估计维生素 K 的摄入量。通过 2006 年国家死亡指数记录来确定死亡率。使用 Cox 比例风险回归来比较充足的维生素 K 摄入量和低摄入量的个体的风险比（HR），并调整晚期 CKD 协变量。为了敏感性分析，还在不同肾脏状况的患者中检查了这些关联。
在中位随访 13.3 年（37408 人年）期间，分别有 1815 人和 876 人因全因和 CVD 死亡。72%的患者维生素 K 摄入量低于推荐的充足摄入量。维生素 K 摄入量高于推荐的充足摄入量的患者，全因死亡率（HR=0.85；95%：0.72-1；P=0.047）和 CVD 死亡率（HR=0.78；95%：0.64-95；P=0.016）均较低。在晚期 CKD 的亚组中进行的敏感性分析得出了类似的发现。
本观察性研究表明，充足的维生素 K 摄入可能与 CKD 患者全因和 CVD 死亡率降低有关。然而，维生素 K 可能是健康饮食的标志物；因此，临床试验可能有助于在独立于健康饮食的情况下阐明维生素 K 的作用。
