Goessel residents used in study
Contributing writer
Some members of the audience at the Tabor College Leaning in Retirement Program Thursday morning had a special interest in hearing Dr. Michael H. Crawford from the department of biological anthropology at the University of Kansas. They had participated in his study reported in Different Seasons, a study of biological aging in the Mennonite population.
Beginning in 1979, Crawford had studied the process of aging in Mennonites in the areas of Goessel, Inman, and Henderson, Neb. He had become curious about why some people live longer and age more slowly than others.
"What allows you to live a long time?" Crawford asked. "Is it lifestyle? Is it genes? Is it environment? Or a combination?"
He considered the Mennonites an ideal population for his study for several reasons. First of all, they keep good records. An attempt to study a population in a mountainous region of Europe, where many people claimed to live well past 100, had foundered on the suspicion that many such individuals were not nearly as old as they said.
For the most part, Mennonites are culturally and genetically homogenous. Most of them do not use alcohol or tobacco, so that the study did not have to allow for bodily damage from these causes. They were cooperative and interested in the research he was doing. Finally, they tend to have large families, which helped in studying genetic factors.
Tests were done for many markers thought to be associated with the aging process, such as hand-eye coordination, motor time, simple reaction time, dominant grip strength, trunk flexibility, pulmonary function, taste sensitivity, and blood chemicals, including cholesterol, triglycerides, thyroxin, and glucose.
"What we were interested in," said Crawford, "was why some people age at a different rate from others."
As expected, most of these functions tended to deteriorate with age, starting at about the age of 50. Two which, surprisingly, did not were the time it takes to make simple decisions and the ability to taste.
It was no surprise to discover that the deterioration does not take place at the same rate in different individuals. The one factor found to be the most genetically controlled was trunk flexibility. As Crawford put it, "If you want to retain trunk flexibility in old age, you have to choose parents with a lot of trunk flexibility."
Other neuromuscular tests revealed a very low rate of heritability, but appear to depend on training, healthful lifestyles, etc. Nevertheless, some families do live slower and age at a slower rate than others. Overall, longevity and the aging process is apparently about 60 percent under genetic control.
Among the markers which best predict longevity are the level of albumin, lipids, and glucose in the blood. Albumin is closely related to kidney function, and lipids contribute to cardiovascular disease.
Perhaps the most exciting part of Crawford's presentation concerned not the completed study, but a future one.
He is now looking for 50 families willing to participate in a study which will try to map genes associated with the biological process of aging.
"The technology is finally there," said Crawford. "Because of the work you did in the 1970's, mapping will now be possible."
In this project, he will need to work with selected families rather than the whole Mennonite population in order to trace genetic factors. "If you are willing to work with us," Crawford challenges, "you'll have the opportunity to change our whole concept of biological aging."
Anyone interested in obtaining a copy of the book which reports the study may order Different Seasons: Biological Aging in Midwestern Mennonites at the following address: University of Kansas, Department of Anthropology, 622 Fraser Hall, 1415 Jayhawk Blvd., Lawrence, Kansas 66045-75576 or by e-mail at kuanthro@ukans.edu. The price is $25.00 plus $2.50 postage and handling.
