Since 1995, Dr. Ryff and her Wisconsin team have been studying some 7, 000 individuals and examining factors that influence health and well-being from middle age through old age in a study called MIDUS, or the Mid-Life in the U.S. National Study of Americans, funded by the National Institute on Aging.
WSJ: University of Wisconsin Study Finds Eudaimonic Happiness Lessens the 'Bite' of Risk Factors for Disease