This invention provides methods of using of the sizes and levels of high-density lipoprotein (HDL) and low-density lipoprotein (LDL) particles, the −641 allele of the promoter of the gene encoding apolipoprotein C-3 (APOC-3), the 405 allele of the gene encoding cholesteryl ester transfer protein (CETP), and plasma levels of insulin-like growth factor-1 (IGF-1), adiponectin, CETP and APOC-3, for determining and increasing an individual's likelihood of longevity and of retaining cognitive function during aging, and for determining and decreasing an individual's likelihood of developing a cardiovascular-, metabolic- or age-related disease.