Glycosylation of Proteins: Lack of Influence of Aging

In elderly nondiabetic individuals, increased glycosylation of hemoglobin has been reported. Most elderly subjects suffer from chronic disorders and consume one or more medications. Thus, it is conceivable that the increased glycosylation of hemoglobin may be secondary to factors other than old age. Furthermore, the data are sparse regarding the effect of aging on glycosylation of other proteins. In this study, glycosylated hemoglobin (GHb), glycosylated protein (GP), glycosylated albumin (GA), and fasting plasma glucose (FPG) concentrations were determined in 93 healthy nondiabetic subjects after an overnight fast. Strict criteria were observed to define the healthy status of these subjects to eliminate the influence of all other factors known to facilitate glycosylation of hemoglobin. No significant correlations were noted between age and FPG, GHb, GP, or GA (P > .05 for all correlations). Furthermore, no significant differences were observed between groups according to age for any of the parameters studied. Therefore, this study demonstrates that aging may not influence glycosylation of proteins in healthy subjects, and the previously observed increase in GHb concentrations in elderly populations may be related to associated factors rather than old age.