Etiology of Individual Differences in Human Health and Longevity

In this chapter, we review of the field of gerontological genetics with respect to subjective and objective health, the role of stress on health, and finally frailty and longevity. For most indices of subjective and objective health, frailty, and longevity, genetic influences contribute only modestly to individual differences, wherein heritabilities are typically on the order of 35%–40%. Notable exceptions are the moderate to strong heritabilities for lipid measures and brain structure and function, with a remarkably increasing role of genetic influences for longevity with advancing age. Although candidate gene and genome-wide association studies (GWAS) studies have identified gene variants associated with many subjective and objective health traits, their effect sizes are typically relatively small, as expected for complex traits. There is some evidence for gene–environment interactions, and stress may be an important moderator of genetic variance for health. For example, carrying a risk genotype for cardiovascular disease (CVD) in the angiotensin converting enzyme gene (