Several diseases such as cataract, macular degeneration, neurodegenerative diseases and atherosclerosis are associated with aging. Almost all of the hubs of the longevity network are involved in at least one age-related disease.

There is a common signature network (588 proteins) of human longevity and major age-related diseases (atherosclerosis, type 2 diabetes, cancer, and Alzheimer's disease). Almost all common signature proteins are strongly interconnected. They contain three quarters of the human interactome hubs and are enriched with signaling proteins that form a scale-free network referred to as the common signaling signature network.

Common features shared between Alzheimer's disease and aging were identified by a systems level analysis of transcriptional changes in Alzheimer's disease and normal aging. Two functional modules representing groups of biologically related genes, one related to mitochondrial processes and the other to synaptic plasticity, were conserved in both.

The analysis of a disease-disease network including 261 aging genes showed that 79 neurological and 20 psychiatric disorders have a strong association with aging providing a molecular connectivity between aging and psychiatric diseases. There is thus a common gene signature of cancer and longevity. Among the common genes, tumor suppressors are associated with increased lifespan and oncogenes with reduced lifespan. Longevity- and cancer-associated proteins have a significantly higher average connectivity than other human proteins and may act in cooperative manner via protein-protein interactions.

The integration of human protein-protein interaction, known disease- and age-gene associations into a disease-aging network showed that aging genes play significant roles in connecting genetic diseases.