Relationship between blood Vitamin C and longitudinal change in physical performance among Japanese community dwelling elderly women

最近的研究表明，抗氧化剂维生素C的摄入量和身体表现之间存在有益的关系。我们在2006年对社区居住的老年妇女进行的一项横断面研究发现，血液维生素C的浓度与体力活动有关。本研究旨在调查老年女性血液中维生素C浓度与身体机能变化的关系，为了提供具有高质量证据的纵向分析，于2009年进行了跟踪调查，并将结果与上述研究的2006年调查结果进行了比较。基线时血液维生素C浓度与随访期间握力变化之间的关系分析显示，（校正基线年龄和握力：r=-0.1，p=0.02）。然而，当排除服用维生素C补充剂的受试者时，没有观察到这种相关性。分析三年期间血液维生素C浓度变化与握力变化之间的关系，显示正相关（r=0.11，P=0.016）。即使排除了服用维生素C补充剂的受试者，也获得了类似的结果（r=0.10，P=0.043）。

Recent studies have suggested that there is a beneficial relationship between antioxidant vitamin C intake and physical performance. A cross sectional study we conducted in 2006 on community dwelling elderly women found that the concentration of blood vitamin C was related to physical performance. The present study aimed to investigate the relationship between vitamin C concentration in the blood and changes in physical performance in elderly women.In order to provide a longitudinal analysis with high quality evidence, a follow-up survey was conducted in 2009 and the results were compared to the 2006 survey results from the aforementioned study, which served as a baseline.Analysis of the relationship between the blood vitamin C concentration at baseline and changes in handgrip strength during the follow-up period showed a negative correlation (adjusted for baseline age and grip strength: r=-0.1, p=0.02). However, this correlation was not observed when the subjects who took vitamin C supplements were excluded. Analysis of the relationship between changes in blood vitamin C concentration and changes in grip strength over the three-year period showed a positive correlation(r=0.11, P=0.016). A similar result was obtained even after the subjects who were taking vitamin C supplements were excluded (r=0.10, P=0.043).