Institute of Nutritional Science, Justus Liebig University, Goethestrasse 55, D-35390, Giessen, Germany.
Eur J Clin Nutr. 2019 Sep;73(9):1307-1315. doi: 10.1038/s41430-018-0367-8. Epub 2018 Dec 4.
BACKGROUND/OBJECTIVES: This study investigates the predictors of serum cobalamin concentrations in community-dwelling older adults and the relationship between serum cobalamin and plasma homocysteine.
SUBJECTS/METHODS: Serum cobalamin and plasma homocysteine were measured by SimulTRAC-SNB radio assay and HPLC, respectively. Linear multiple regression analyses were performed with cross-sectional data of 352 participants aged 60-90 years to examine (1) the predictors of serum cobalamin and (2) the association between cobalamin and homocysteine status. Age, sex, body composition, diet, supplement use, smoking, serum folate, serum pyridoxal 5´-phosphate, serum creatinine, and selected diseases were considered as potential predicting/confounding factors.
Median values of serum cobalamin, plasma homocysteine, and dietary cobalamin intake were 256 pmol/L, 9.7 µmol/L, and 5.7 µg/day, respectively. In multiple regression analysis, cobalamin intake, sex, body composition, serum creatinine and smoking did not predict serum cobalamin (all P > 0.05). In contrast, age (β = 0.111, P = 0.031), serum folate (β = 0.410, P < 0.001) and diagnosis of chronic inflammatory bowel disease (IBD) (β = 0.101, P = 0.037) were positively and cancer diagnosis (β = -0.142, P = 0.003) was negatively associated with serum cobalamin. The model explained 23% of the variability of serum cobalamin. After exclusion of subjects with IBD/cancer diagnosis and/or vitamin B/multi-vitamin supplementation, only serum folate remained as positive predictor of serum cobalamin (β = 0.407, P < 0.001). Serum cobalamin was positively associated with inverse-transformed plasma homocysteine before (β = 0.298, P < 0.001) and after (β = 0.199, P < 0.001) multiple adjustments.
Serum folate but not cobalamin intake or age proves to be a main predictor of cobalamin status. Nevertheless, independent of serum folate and other potential confounders, serum cobalamin is inversely associated with plasma homocysteine.
背景/目的：本研究旨在调查社区老年人血清钴胺素浓度的预测因素，以及血清钴胺素与血浆同型半胱氨酸之间的关系。
受试者/方法：采用 SimulTRAC-SNB 放射性分析和 HPLC 法分别测定血清钴胺素和血浆同型半胱氨酸。对 352 名年龄在 60-90 岁的参与者的横断面数据进行线性多元回归分析，以检验（1）血清钴胺素的预测因素和（2）钴胺素与同型半胱氨酸状态之间的关系。年龄、性别、身体成分、饮食、补充剂使用、吸烟、血清叶酸、血清吡哆醛 5'-磷酸、血清肌酐和选定的疾病被认为是潜在的预测/混杂因素。
血清钴胺素、血浆同型半胱氨酸和膳食钴胺素摄入量的中位数分别为 256 pmol/L、9.7 μmol/L 和 5.7 μg/天。多元回归分析显示，钴胺素摄入量、性别、身体成分、血清肌酐和吸烟均不能预测血清钴胺素（均 P>0.05）。相反，年龄（β=0.111，P=0.031）、血清叶酸（β=0.410，P<0.001）和慢性炎症性肠病（IBD）的诊断（β=0.101，P=0.037）与血清钴胺素呈正相关，而癌症诊断（β=-0.142，P=0.003）与血清钴胺素呈负相关。该模型解释了血清钴胺素变异性的 23%。排除 IBD/癌症诊断和/或维生素 B/多种维生素补充的受试者后，只有血清叶酸仍然是血清钴胺素的阳性预测因子（β=0.407，P<0.001）。血清钴胺素与未调整（β=0.298，P<0.001）和调整后（β=0.199，P<0.001）的血浆同型半胱氨酸呈正相关。
血清叶酸而不是钴胺素摄入或年龄被证明是钴胺素状态的主要预测因素。然而，独立于血清叶酸和其他潜在的混杂因素，血清钴胺素与血浆同型半胱氨酸呈负相关。
