Unfortunately, most of what we all know is a confusing mix of fact and fiction, of myth and reality. Some of the common myths are dispelled in the book Successful Aging by John W. Rowe, M.D. and Robert L. Kahn, Ph.D., published in 1989.
The book gives results of extensive studies of aging funded by the John D. and Katherine T. MacArthur Foundation. An earlier post dealt with three common myths of aging .
Another common myth is that bad health is caused by bad genes. Therefore—other than having picked different parents—there’s nothing you can do about our health as you grow older.
You’ve probably all heard a person say something like, “My Dad died of a heart attack at 54, and Grandpa died of one when he was only 49.” Generally such explanations are offered with a look of deep resignation and regret.
The man speaking is doomed to an early death, and there’s nothing he can do but accept the inevitable. And perhaps console himself with generous servings of barbecued ribs and French fries.
Obviously, there is a connection between genetics and aging. It’s well known, for example, that the length of life of non-identical twins (genetically no more similar than any two children born to the same parents) varies much more than that of identical twins (who are genetically identical).
When there are similarities in a family, is it the results of genes or the environment or a combination of the two? You’ll recognize this as the familiar Nature versus Nurture argument. To answer this perennial question, the MacArthur research considered the role of genes in several aspects of aging:
Effect of genes on disease and disability
Some genetic diseases do clearly shorten life. A few are caused by a single gene. For example, if a person has Huntington’s disease, his or her children have a 50% chance of inheriting the gene from that parent. A child who inherits the gene will get the disease, unless, of course, he dies of some other cause before the disease manifests itself.
For all but a small number of conditions like Huntington’s disease, however, the MacArthur studies show that a person’s environment and lifestyle have a powerful effect on the likelihood that he will actually develop a disease.
It’s true that a family history of heart disease, some cancers, high blood pressure, familial high cholesterol, rheumatoid arthritis, and certain other diseases may put a person at risk, but that doesn’t mean that he or she will necessarily develop the disease. The authors conclude
We now know that diet, exercise, and even medications may delay or completely eliminate the emergence of the disease. Genes play a key role in promoting disease, but they are certainly less than half the story.
Effect of genes on mental and physical function
To separate the effects of genetics from those of environment, the MacArthur researchers turned to that staple of Nature versus Nurture studies, namely twins reared apart.
A digression here: Am I the only one who wonders why there seem to be so many twins reared apart? I mean, does a couple have identical twins and give one away because they don’t want identical children? Or do they give away one twin out of the goodness of their hearts to a couple which hasn’t been able to conceive a child?
Anyway, such studies clearly indicated that
- “…with rare exceptions, only about 30% of physical aging can be blamed on the genes” and
- As we grow older, genetics becomes less important, and environment becomes more important.
Rowe and Kahn conclude that the likelihood of conditions, such as obesity and hypertension, are largely not inherited and thus these risks are due to environmental and life style factors.
How we live and where we live has the most profound impact on age-related changes in the function of many organs throughout the body— including the heart, immune system. lungs, bones, brain, and kidneys.
Again, the reality offers so much more hope and inspiration than the myth you’ve heard so many times.
And you’ve probably met some one with a family history of heart attacks at a youngish age, for example, who works hard to avoid the same fate. Like my friend Robert in Seattle who runs and bikes and dances with amazing energy.
Do you know any one like that? Are you are like that.
Photo by vramak