Lower klotho in women with chronically high stress suggests an interactive role for the psychosocial environment in systemic levels of a biological factor that influences longevity,3, 7, 25 brain function12, 26, 48 and body health.25 This is important because it establishes a link between life experience and levels of circulating klotho—in addition to known influences on its levels from genetic KLOTHO variation,12, 23 aging,28, 42 kidney disease49 and Alzheimer's disease.50 This evidence concerns the gene KL and Alzheimer disease.