This month’s Atlantic cover-story, on a group of 268 Harvard men whose entire lives were studied as they unfolded, makes for fascinating and engaging reading. A sample:

What allows people to work, and love, as they grow old? By the time the Grant Study men had entered retirement, Vaillant, who had then been following them for a quarter century, had identified seven major factors that predict healthy aging, both physically and psychologically.

Employing mature adaptations was one. The others were education, stable marriage, not smoking, not abusing alcohol, some exercise, and healthy weight. Of the 106 Harvard men who had five or six of these factors in their favor at age 50, half ended up at 80 as what Vaillant called “happy-well” and only 7.5 percent as “sad-sick.” Meanwhile, of the men who had three or fewer of the health factors at age 50, none ended up “happy-well” at 80. Even if they had been in adequate physical shape at 50, the men who had three or fewer protective factors were three times as likely to be dead at 80 as those with four or more factors.

What factors don’t matter? Vaillant identified some surprises. Cholesterol levels at age 50 have nothing to do with health in old age. While social ease correlates highly with good psychosocial adjustment in college and early adulthood, its significance diminishes over time. The predictive importance of childhood temperament also diminishes over time: shy, anxious kids tend to do poorly in young adulthood, but by age 70, are just as likely as the outgoing kids to be “happy-well.”

On the other hand, I can’t help but feel a certain sense of unease and trepidation while reading this. What stands out most starkly for me is the sheer difficulty of being happy; of leading the sort of life in which we avoid poisoning our own relationships, and end up feeling like we accomplished something meaningful. The Grant study men had a plethora of built-in advantages: they were the elite class of the richest, most powerful country in the world - yet still, so many of them failed. Is it excessively pessimist to wonder how much chance the rest of us have?