Human form shows robust changes in past century

July 30, 2006|By GINA KOLATA | GINA KOLATA,NEW YORK TIMES NEWS SERVICE

Valentin Keller enlisted in an all-German unit of the Union Army in Hamilton, Ohio, in 1862. He was 26, a small, slender man, 5 feet 4 inches tall, who had just become a naturalized citizen.

He listed his occupation as tailor.

A year later, Keller was honorably discharged, sick and broken. He had a lung ailment and was so crippled from arthritis in his hips that he could barely walk.

He died at age 41 of "dropsy," which probably meant that he had congestive heart failure. His 39-year-old wife, Otilia, died a month before him of what her death certificate said was "exhaustion."

People of Valentin Keller's era, like those before and after them, expected to develop chronic diseases by their 40s or 50s. Keller's descendants had lung problems, they had heart problems, they had liver problems. They often died in their 50s or 60s.

Now, though, life has changed. The family's baby boomers are reaching middle age and beyond and are doing fine.

"I feel good," says Keller's great-great-great-grandson, Craig Keller. At 45, Keller says he has no health problems, nor does his 45-year-old wife, Sandy.

The Keller family illustrates what may prove to be one of the most striking shifts in human existence - a change from small, relatively weak and sickly people to humans who are so big and robust that their ancestors seem almost unrecognizable.

New research from around the world has begun to reveal a picture of humans today that is so different from what it was in the past that scientists say they are startled. Over the past 100 years, says one researcher, Robert W. Fogel of the University of Chicago, humans in the industrialized world have undergone "a form of evolution that is unique not only to humankind, but unique among the 7,000 or so generations of humans who have ever inhabited the Earth."

The difference does not involve changes in genes, as far as is known, but changes in the human form. It shows up in several ways, from those that are well known and almost taken for granted, like greater heights and longer lives, to ones that are emerging only from comparisons of health records.

The biggest surprise emerging from the new studies is that many chronic ailments such as heart disease, lung disease and arthritis are occurring an average of 10 years to 25 years later than they used to. There is also less disability among older people today, according to a federal study that directly measures it. That is not just because medical treatments such as cataract surgery keep people functioning. Human bodies are simply not breaking down the way they did before.

Even the human mind seems improved. The average IQ has been increasing for decades, and at least one study found that a person's chances of having dementia in old age appeared to have fallen in recent years.

The proposed reasons are as unexpected as the changes themselves. Improved medical care is only part of the explanation; studies suggest that the effects seem to have been set in motion by events early in life, even in the womb, that show up in middle and old age.

"What happens before the age of 2 has a permanent, lasting effect on your health, and that includes aging," said Dr. David J.P. Barker, a professor of medicine at Oregon Health and Science University in Portland and a professor of epidemiology at the University of Southampton in England.

Each event can touch off others. Less cardiovascular disease, for example, can mean less dementia in old age.

The effects are not just in the United States. Large and careful studies from Finland, Britain, France, Sweden and the Netherlands all confirm that the same things have happened there; they are also beginning to show up in the underdeveloped world.

Of course, there were people in previous generations who lived long and healthy lives, and there are people today whose lives are cut short by disease or who suffer for years with chronic ailments. But on average, the changes, researchers say, are huge.

Even more obvious differences surprise scientists by the extent of the change.

In 1900, 13 percent of people who were 65 could expect to see 85. Now, nearly half of 65-year-olds can expect to live that long.

People even look different today. American men, for example, are nearly 3 inches taller than they were 100 years ago and about 50 pounds heavier. "We've been transformed," Fogel said.

Today's middle-aged people are the first generation to grow up with childhood vaccines and with antibiotics. Early life for them was much better than it was for their parents, whose early life, in turn, was much better than it was for their parents.

And if good health and nutrition early in life are major factors in determining health in middle and old age, that bodes well for middle-aged people today. Investigators predict that they might live longer and with less pain and misery than any previous generation.

"Will old age for today's baby boomers be anything like the old age we think we know?" Barker asked. "The answer is no."

Animal studies and data that Barker and others have been gathering have convinced him that health in middle age can be determined in fetal life and in the first two years after birth.

His work has been controversial. Some say that other factors might be responsible. But Barker has won over many scientists.

In one study, he examined health records of 8,760 people born in Helsinki from 1933 to 1944. Those whose birth weights were below about 6.5 pounds and who were thin for the first two years of life, with a body mass index of 17 or less, had more heart disease as adults. Another study, of 15,000 Swedish men and women born from 1915 to 1929, found the same thing.

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