Triumphs of Experience: The Men of the Harvard Grant Study (33 page)

Table
7.2
Factors Associated with Irreversible Physical Health Decline Before Age 55

Very Significant = p<.001; Significant = p<. 01; NS = Not Significant.

I had made my case; mental illness was very important in hastening the aging process. Every five years I’d trot out these six variables and run them again, looking to see if they were still statistically important factors in looking at physical health. For fifteen years, they were. So far, so good. But alas, like the Science Museum computer, I had not fully controlled for other important risk factors. It took several decades before I statistically separated decline in health after age fifty-five from decline in health before age fifty-five. In retrospect,
that
should have been a no-brainer. Yet another of the many advantages of longitudinal studies is that they uncover sloppy thinking.

Study II, 2000: Decline in health between fifty-five and eighty.
As the men began passing eighty, I was starting to wonder what factors might be associated with the development of dementia. The fact that there is frequently a vascular component to this dread condition led me to establish a five-point scale of vascular risk factors: smoking, alcohol abuse, hypertension, obesity, and Type II diabetes. For the first time I examined the five factors not only individually but as a group; summing risk factors increases their predictive power. When these factors proved to be strongly associated with dementia, I turned them loose on the larger question of physical health in general. And that led to some big surprises.

This time I followed until they were eighty the 177 men who had still been healthy or had had only minor illnesses at fifty-five. And I found with astonishment that the relationship between mental and physical health that had seemed so clear when the men were fifty-five no longer held. As
Table 7.3
illustrates, the deterioration of the men’s health between ages fifty-five and eighty was very significantly associated with the vascular risk factors, and not at all with the mental health risk factors. Of the 189 healthy men selected at age forty, 103 had no risk factors, and 86 had one or more. Sixty-five (that is, 76 percent) of the latter group were chronically ill or dead by their eightieth year. Of the men with no risk factors, only 45 (44 percent) were dead or disabled. This was a very significant difference.

But the early mental health risk factors predicted nothing about health at eighty. It appears that they did their damage early. The effects of past damage endured, and remained statistically significant even when the effects of alcohol, tobacco use, obesity, and ancestral longevity were controlled. The river of time flowed on, but poor mental
health
did no further damage. The vascular risk factors, as I documented subsequently (see
Table 7.3
), were important before fifty-five as well as after, a fact at first unsuspected by this young research psychiatrist. Maturity improves the discernment of researchers,
too!

Table
7.3
Factors Associated with Irreversible Physical Health Decline at Different Age Periods

Very Significant = p<.001; Significant = p<. 01; NS = Not S

Study III, 2011: Getting to ninety.
The men got older, and I continued to try to identify the variables that allowed some of them to age successfully to ninety. I kept my eye on the vascular risk factors, and again I saw a pair of once-important variables lose their statistical significance as time went by. When the men were between eighty and ninety, the vascular factors as a summed total were still significant. Because so few heavy smokers and alcoholics survived into the ninth decade, however, the significance of those two individual factors faded after eighty. Of the forty-five heavy Study smokers, only sixteen were still alive at eighty and only four at ninety. Only three of the alcohol-dependent men lived until eighty and none until ninety. But the other vascular risk factors told a different story. They continued to affect the men’s ability to remain cognitively sharp after eighty; and after eighty dementia was a major source of health decline. Of the men with no vascular risk factors, 50 percent were still alive at ninety, instead of the expected 30 percent. Of the seventeen men with three or four risk factors, all but one was dead ninety years after his birth.

Table 7.3
sums up the findings of all three of these studies; the first column refers not to the original analysis of the age fifty-five data, but to my later reappraisal, which coded individually for vascular and genetic risks. N in each column refers to living men; one of the reasons that predictive associations change is that certain risk factors, like badly adapted parasites, kill off their hosts, leaving themselves with nothing left to live on.

Study IV, 2012: How to live forever.
In 2012, as I write this, sixty-eight of the active Grant Study men are still alive; fifty are still cognitively
intact.
I wanted to learn what I could about what makes for good health and good mentation over so many years. Ideally this study will be done again ten years from now, by which time we will know exactly when each of the men died. But to bring it all together in a provisional way, I made the best estimate I could of how much longer the men would live, based on past experience. I added seven years to a man’s current age if he still had only minor health problems, five years if he was chronically ill, and three years if he was disabled. Obviously there’s speculation here, but after the age of ninety there’s a limit to how wrong the guess can be. Then I plotted all the men’s lifespans against many factors that had been significant in other contexts to see what I could learn about their relationship to longevity.
Table 7.4
is the result.

Men with no vascular risk factors lived to an average age of eighty-six. Men with three or more lived to an average age of only sixty-eight. This complex of factors subtracted eighteen years from a man’s expected life. The difference in longevity between men with very long- and very short-lived ancestors was seven years—eighty-four years as opposed to seventy-seven—a significant difference, but nothing like that predicted by the vascular risk factors. Surprisingly, parental social class made less than a year’s difference. The men with the very best and worst adjustments at forty-seven lived to eighty-five and seventy-seven respectively—an eight-year difference in longevity that was very significant, but again far less than that produced by the vascular risk factors.

A curiosity: the sixteen men with the most combat exposure in World War II died significantly younger than the rest of the sample. They were six times as likely to die from unnatural causes (e.g., murder, suicide) and they were twice as likely to die before eighty. This is another of those unanticipated findings that in the coming years may turn out to be a clue to something unexpected and important.

An interesting independent predictor of longevity, which I recog
nized
only after Friedman and Martin published
The Longevity Project
in 2011, was the presence or absence in college of personality characteristics of perseverance and self-motivation (in the early Study terminology,
Well Integrated
and
Self-Driving
).
23
These traits were significantly associated with longevity; the twenty-three men who manifested both in college were likely to live ten years longer than the men with neither trait (see
Table 7.4
).

Table
7.4
Factors Associated with Longevity (Mean Age at Death 81.5; N = 237)

Very Significant = p<.001; Significant = p<. 01; NS = Not Significant.

HOW
NOT
TO LIVE FOREVER

Most of the deaths before fifty-five were associated with factors over which the men had no control. We cannot pick our parents, or control the genes that lead to major depression. The vascular factors that were so strongly implicated in deaths after fifty-five, however, are a different story. They are all now widely accepted as causes of death before eighty, and we were able to confirm this. Using multiple regression analysis (unlike the Boston Museum of Science computer!) to investigate each of the five factors in the context of the other four, we found that each one made an independent contribution to health decline and death.
24
As
Table 7.3
illustrates, there was a very significant association between these factors and irreversible decline in health in the Grant Study men. The risk factors were of equal importance in the Glueck Inner City cohort and the Terman cohort of gifted women.
25
But unlike the previously cited mental health factors, they are causes of early death over which we have considerable control. At the end of the day, good self-care before age fifty—stopping smoking, joining AA, watching the weight, and controlling the blood pressure—made all the difference in how healthy the men were at eighty and ninety.

Education is another factor to be reckoned with when it comes to health; it turned out to be critically important to the health of the Inner City sample (and modestly important for the Grant Study men,
whose
educational baseline was higher). The average College man who never sought post-graduate education had a life expectancy of seventy-nine years, while for the men with post-graduate educations, life expectancy was eighty-three years—a very significant difference. Years of education were powerfully associated with reduction of all of the five factors affecting vascular health. This was especially true of the Inner City men. This issue will be dealt with more fully in
Chapter 10
.

OUT OF OUR HANDS?

However, one interesting piece of conflicting evidence suggests that we still have to reckon with our stars. A recent paper by Thomas Perls and his colleagues on a cohort of 800-plus centenarians suggests that genes are just as important to survival past one hundred as lifestyle.
26
In
Aging Well
I could assert that ancestral longevity was not an important predictor of survival from fifty-five to eighty. But to live past eighty, it appears, ancestral longevity again assumes significance. Another reminder that follow-up must continue as long as life does.

Cancer.
Cancer is an increasingly important cause of death after seventy, and this was another factor that often seemed to lie in the men’s stars—or, if you prefer, in their genes. With the exception of lung cancer, which is closely tied to smoking, cancer in the Grant Study seemed surprisingly independent of both mental health and the vascular risk factors. In larger samples, however, and in studies focused on specific cancers, environment, dietary and sexual habits, and alcohol abuse can also be demonstrated to be important.

Age and cognition.
We used the Telephone Interview for Cognitive Status, or TICS, to measure cognitive skills in men without an existing diagnosis of dementia.
27
In the Grant Study, the factors most associated
with a high TICS score appeared to be the absence of vascular risk factors, good vision, college IQ and class rank, exercise at sixty, and, surprisingly, a warm relationship with one’s mother when young. This is another curiosity. As we’ve gone along, I’ve pointed out that a warm childhood relationship with his mother—not maternal education—was significantly related to a man’s verbal test scores, to high salary, to class rank at Harvard, and to military rank at the end of World War II. At the men’s twenty-fifth reunion, it looked, to my surprise, as though the quality of a man’s relationship with his mother had little effect on overall midlife adjustment. However, forty-five years later, to my surprise again, the data suggested that there
was
a significant positive correlation between the quality of one’s maternal relationship and the absence of cognitive decline. At age ninety, 33 percent of the men with poor maternal relationships, and only 13 percent of men with warm relationships, suffered from dementia.