Longitudinal age-related changes in cobalamin and folate status in community-dwelling older adults

Advancing age is regarded as a risk factor for an insufficient cobalamin and folate status. However, longitudinal data are lacking and little is known on the impact of age in subjects ≥ 60 years after considering potential confounding factors. Therefore, the present study investigates age-related changes in cobalamin and folate status in older adults by using longitudinal data of 332 German subjects aged ≥ 60 years, who participated in the longitudinal study on nutrition and health status of senior citizens in Giessen (GISELA study). All subjects had complete data records on at least three follow-ups between 1997 and 2014. The mean follow-up time was 12 years. Fasting serum concentrations of cobalamin and folate were determined with SimulTRAC-SNB radio assay kit. In each follow-up, body composition (bioelectrical impedance analysis), dietary cobalamin and folate intakes (3-day estimated dietary record), supplement use and lifestyle factors (questionnaires) were assessed. Linear mixed models were used to analyze age-related changes in serum concentrations of cobalamin and folate by considering sex, absolute fat-free mass, supplement use, dietary intakes and smoking behavior as potential confounding variables. Furthermore, due to the metabolic interaction of cobalamin and folate, linear mixed models implemented a mutual adjustment of serum cobalamin and serum folate. At baseline, 11.4 % and 7.8 % of the subjects had cobalamin concentrations < 148 pmol/L and folate concentrations < 10 nmol/L, respectively. In contrast, dietary cobalamin intakes < 4 μg/d and folate intakes < 300 μg/d were found in 24.4 % and 76.5 % of the subjects, respectively. Without adjustments, a positive influence of age on serum cobalamin [parameter estimate (95 % CI) = 4.57 (1.67, 7.46)] and serum folate [0.29 (0.18, 0.40)] was found. After multiple adjustments, age was still a positive predictor of serum folate [0.25 (0.14, 0.36)], whereas no significant influence on serum cobalamin was found [2.73 (-0.23, 5.69)]. Similar results were noticed when the analyses were restricted to non-users of B-vitamin/multi-vitamin supplements. In conclusion, the present study in community-dwelling subjects does not confirm age-related declines in serum concentrations of cobalamin and folate between the ages of 60 and 90 years. Although a significant proportion of the subjects showed dietary intake levels below the current European references values, serum concentrations of cobalamin and folate were p