Study design and results summary. A) CD14+ monocytes were purified from 1,264 peripheral blood samples by magnetic bead selection, and gene expression levels were measured using microarray. Age-associated expression (FDR ≤ 0.01) was detected for 4,502 genes, which were further analyzed using the indicated in silico approaches to identify and investigate potential age-related pathways. Results support a potential transcriptomic decline in ribosomal protein synthesis machinery, as well as declines in oxidative phosphorylation and autophagy gene expression with age. Measures of DNA methylation and pulse pressure were incorporated to investigate DNA methylation as a potential mediator for the effect of age on gene expression, and to prioritize age-associated gene expression for potential relevance to vascular age. B) CD4+ T cells were purified in a subset of the peripheral blood samples by magnetic bead selection, and gene expression levels were measured using microarray. Age-associated genes (FDR < 0.01) were identified, revealing 30 genes with expression significantly associated with age in both monocytes and T cells from the same individuals. No pathways were significantly (FDR < 0.05) enriched among age-associated genes in T cells; however, suggestive evidence was observed for the ribonucleoprotein complex and immune response pathways.