From a HarvardMagazine.com online archive article:

Six factors measured by age 50 were excellent predictors of those who would be in the “happy-well” group–the top quartile of the Harvard men–at age 80: a stable marriage, a mature adaptive style, no smoking, little use of alcohol, regular exercise, and maintenance of normal weight. At age 50, 106 of the men had five or six of these factors going for them, and at 80, half of this group were among the happy-well. Only eight fell into the “sad-sick” category, the bottom quarter of life outcomes. In contrast, of 66 men who had only one to three factors at age 50, not a single one was rated happy-well at 80. In addition, men with three or fewer factors, though still in good physical health at 50, were three times as likely to be dead 30 years later as those with four or more.

The book examines the lives of a group of Harvard men who have been studied from their college years all the way to retirement and, in some cases, death. Its cornerstone is the Grant Study, a longitudinal investigation conceived in 1937 and launched at Harvard in 1939. With funding from dime-store magnate W. T. Grant, researchers signed up 268 members of the classes of 1941 through 1944, in their sophomore years, for an in-depth, lifelong study of “normal” adult development.

To read more click on the following link: https://harvardmagazine.com/2019/08/the-talent-for-aging-well