In this thesis I investigated the association of genetic variants and metabolites in blood with aging and age-related outcomes by making use of a multi-omics approach and data from cohort studies across the world. The studies included in this thesis resulted in the identification of promising genetic variants, genes, and metabolites associated with age-related outcomes such as telomere length, depression, sleep latency and sleep apnea. The findings of this thesis contribute to a better understanding of the molecular mechanisms involved in age-related outcomes. The presented findings will provide targets for earlier diagnosis, new treatments and new prevention strategies for age-related diseases to improve healthy aging.