Effect of age on plasma homocysteine concentrations in young and elderly subjects considering serum vitamin concentrations and different lifestyle factors.

Objectives: The aim of this study was to investigate whether an increase in total homocysteine (tHcy) concentration with increasing age is due to diminishing serum concentrations of pyridoxal-5-phosphate (PLP), vitamin B-12, and folate. The possible influence of different lifestyle factors on tHcy concentration was considered.
Methods: Plasma tHcy, serum concentrations of pyridoxal-5-phosphate, vitamin B-12, and folate, intake of coffee and tea, alcohol, and methionine, as well as cigarette smoking, were determined in 252 elderly subjects (60-87 years old) of the longitudinal study on nutrition and health status in an aging population in Giessen (GISELA) and 99 young adults (20-34 years old) of the study on health and nutrition of young adults (GEJE).
Results: Mean plasma tHcy concentrations were significantly higher in elderly than in young female subjects (9.7 +/- 1.9 micromol/L vs. 9.0 +/- 1.6 micromol/L, p < 0.05), but there was no difference between elderly and young men (10.6 +/- 2.1 micromol/L vs. 10.7 +/- 2.6 micromol/L). No differences in tHcy were observed between young and elderly subjects after adjustment for serum concentrations of PLP, vitamin B-12, and folate. Multiple linear regression analysis revealed a significant influence of age only in elderly, but not in younger subjects.
Conclusion: Higher tHcy concentrations in the elderly, in comparison to younger women, are due to lower serum concentrations of PLP, vitamin B-12, and folate, whereas within the age group of elderly subjects alone tHcy concentrations increase with age irrespective of serum vitamin concentrations.