Abstract
Background/objectivesThis study investigates the predictors of serum cobalamin concentrations in community-dwelling older adults and the relationship between serum cobalamin and plasma homocysteine.Subjects/methodsSerum 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.ResultsMedian 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.ConclusionsSerum 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.
Highlights
There is an ongoing debate on whether cobalamin intake should be increased in advanced age compared to younger ages
Higher reference values for older adults are discussed, as well as the necessity of cobalamin supplements in advanced age. This is based on observations that older individuals more often have an inferior cobalamin status [1,2,3], which might contribute to an age-related decline in cognitive function and an increased risk of
The observed lower levels of cobalamin status parameters in these studies were not accompanied by classical hematological manifestations [6]; second, boundary values used to classify cobalamin deficiency or insufficiency are still under debate [3]; third, results regarding potential associations of either low serum cobalamin or cobalamin intake with cognitive decline [7,8,9] and cardiovascular diseases [10,11,12,13] are inconsistent
Summary
There is an ongoing debate on whether cobalamin intake should be increased in advanced age compared to younger ages. Higher reference values for older adults are discussed, as well as the necessity of cobalamin supplements in advanced age. This is based on observations that older individuals more often have an inferior cobalamin status [1,2,3], which might contribute to an age-related decline in cognitive function and an increased risk of. The observed lower levels of cobalamin status parameters in these studies were not accompanied by classical hematological manifestations [6]; second, boundary values used to classify cobalamin deficiency or insufficiency are still under debate [3]; third, results regarding potential associations of either low serum cobalamin or cobalamin intake with cognitive decline [7,8,9] and cardiovascular diseases [10,11,12,13] are inconsistent.
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