Serum cobalamins in the elderly: a longitudinal study of a representative population sample from age 70 to 81.

In a representative population sample (n = 973) born 1901-1902 and examined at the ages of 70, 75, 79, and 81, the change in serum cobalamins with increasing age was studied by trend analysis using values obtained in single individuals at all four examinations. In subsamples without definable disorders, the mean annual decline was: among men 3.4 pmol/l (p less than 0.05), among women 3.2 pmol/l (n.s.). The decline was possibly more pronounced among individuals with low and intermediate concentrations. The health-related lower reference limits (the 2.5 percentile values of subsamples without definable disorders) did not differ significantly between sexes and age groups, but low concentrations or ongoing cobalamin medication became more common with advancing age. The results indicate a slight fall in serum cobalamins between age 70 and 81 but do not call for age-related lower reference limits.