By LEE BOWMAN
Scripps Howard News Service
March 30, 2009
Today, of course, we know the biology of aging is much less cut and dried. Sure, 50 is the new 40, etc. There are seemingly an endless array of biological markers, from lung capacity to blood pressure and beyond, that can rate some of us far younger than our years, others of us years older than we actually are.
While the worth of many of those measurements is still open to debate, it's becoming clear that the habits and experiences of our youth and young-adult lives have a major impact on what kind of shape we find ourselves in when we roll past 30 or 40.
Several recent studies have found signs of blood vessel damage similar to that seen in older people with heart disease among obese children as young as 10 and no older than 18. More children than ever are being diagnosed with Type 2 diabetes, high blood pressure and other conditions normally associated with middle age.
Yet diet and exercise and smoking and drinking habits can all change for the better at any age and still show some benefit.
Lately, researchers are finding that in some respects, even aging related to the brain begins well before our 30s.
One report published last year in The New England Journal of Medicine found a link between obesity and reduced levels of a nerve cell growth factor that's key to making new brain cells and preserving the health of existing gray matter.
Another report, from researchers at the University of California-Los Angeles, indicates that stressful times during the teenage years can actually translate to higher levels of a heart-damaging protein on into adulthood.
The study, involving 69 teens with an average age of 17, found that those who reported more negative exchanges with family, friends or teachers in a two-week diary, had higher levels of the inflammatory marker C-reactive protein in blood samples taken an average of eight months later. The results will appear in an upcoming issue of the journal Psychosomatic Medicine.
"Most research on stress and inflammation has focused upon adulthood, but these results show such links can occur as early as the teenage years, even among a healthy sample of young men and women," said Andrew Fulgini, a professor of psychiatry who led the study. "That suggests that alterations ... that initiate cardiovascular disease begin before adulthood."
At the same time, scientists are still grappling with what constitutes a fully mature brain, and what the implications are for development and the onset of aging.
Although the structures of the brain in a 10-year-old are difficult to tell from someone in their 20s, researchers know that much of the advanced connections between the parts of the brain involved in planning, control of primal emotion and other functions aren't formed fully until the early 20s. Many experts think this argues for delays in everything from adult legal accountability to the ability to drive or vote.
But new research from scientists studying aging at the University of Virginia carries the somewhat disheartening news that we no sooner reach the age of wisdom before many of our mental abilities start to slip.
Researchers studied 2,000 men and women aged 18 to 60 over seven years, having them take standardized tests that involve solving puzzles, recalling words or story details or spotting patterns in letters and symbols.
They report in the journal Neurobiology of Aging that on 9 out of 12 tests, the average age at which top performance was achieved was 22.
And the first age at which performance on any of the tests began to appreciably drop was 27 -- on three tests of reasoning, speed of thought and spatial visualization.
Skill on tests involving memory started to fall off after 37, and for several other tests, decline set in by age 42.
However, there was some longevity advantage: people did better on tests that relied on accumulated knowledge, such as vocabulary or general information, all the way up to age 60.
Lead author Timothy Salthouse, a professor of psychology, said the results argue for starting therapies designed to prevent or reverse age-related mental decline well before people approach retirement age.
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