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April 27, 2006

Researcher offers some surprises to aid longevity

Want to live to be 90? While many old-timers attribute their longevity to clean living, perhaps the more scientific recipe is one that includes more wine and socializing, daily coffee and even a little weight gain as the golden years approach.

The surprising results are part of a new study of people who’ve reached the age of 90 and beyond.

Researcher Claudia Kawas, a professor of neurology and neurobiology and behavior at the University of California at Irvine, discussed preliminary results in her talk, “Clinical and Pathological Studies of the Oldest Old: The 90+ Study,” as the most recent presenter in the Graduate School of Public Health’s Jay L. Foster Memorial Lecture series.

In her April 11 talk, Kawas noted that life expectancy has increased by 27 years in the past century. “It’s been amazing and I thought that we had reached more or less a threshold for increasing life expectancy,” she said, adding that the figure continues to rise. “In the last three years alone life expectancy has gone up more than six months,” she said.

Today, there are 2 million Americans aged 90 and older, but by mid-century, their numbers will grow to 10 million, or one out of every 50 people in the United States, Kawas said.

With so many of us heading along the path to longer life, studying the keys to healthy aging becomes more relevant.

“We’re continuing to add years and, obviously, all of us want to reach those years in the best shape possible. Because the individuals who are living into their 10th or 11th decades are truly pioneers, we actually know very little about them,” she said.

Kawas said little is known about dementia in the very elderly population. “We don’t know the incidence rate of dementia; we don’t even know if the dementia people get is Alzheimer’s,” she said, citing studies that show about half the people who die in their 90s don’t have Alzheimer’s disease. What’s more, “About half of the people who die with dementia in their 90s do not appear to have any of the common causes of dementia we now recognize,” she said.

Previous studies on the onset of dementia have yielded varying results. Some suggest that the risk of dementia doubles every five years between the ages of 65 and 85, but decreases after that age. Others show no end to the exponential rise, some show a leveling off, and still others show a gender-based difference that finds women will continue with an exponential rise in risk while men’s risk levels off.

Kawas posited that the wide-ranging results can be a function of the numbers of people studied. “Most studies have a very small number of people in that age range,” she said.

Kawas’s research, “Clinical and Pathological Studies of the Oldest Old: The 90+ Study,” aimed to learn more about longevity as well as dementia and its clinical path.

Her study of people ages 90+ focuses on people living in the Leisure World retiree community in Laguna Woods, Calif. The town, where the mean age is 79, ranked as the nation’s oldest city in the 1990 census.

The 90+ project follows a number of residents from among 14,000 people who participated in a 1981 study on health promotion and disease prevention. Of the original subjects, 1,150 still were alive and at least 90 years old as of Jan. 1, 2003. Of that total, 83 percent enrolled and provided some data for Kawas’s study.

Kawas looks for longevity-related trends in participants’ weight, exercise, diet and social activities and, in women, estrogen use.

The use of estrogen replacement therapy appeared to result in a 6 percent reduction in mortality. The study found the dose didn’t appear to matter, but the duration did.

The women who took estrogen for three or fewer years showed no significant reduction in mortality, but those who used it 15 or more years had almost a 20 percent reduction. A smaller reduction in mortality was found for those who’d used it 4-14 years.

“You can imagine with all the clinical trials on estrogen, making it look like the worst thing since arsenic. And we just add one more observational study making it look like even if it gives you heart attacks and dementia maybe it makes you live longer. But I think the important thing will be when we do this with the dementia outcomes and see what happens there,” Kawas said of the results.

The study also examined weight changes from age 21.

Not surprisingly, “Being obese at age 21 carried with it an increased mortality rate in later life,” Kawas said. But, among the 90+ study participants who were obese at 21, those who lost weight later fared worse than those gained more weight late in life.

“I’m not sure what to do with this, but it sure looks like losing weight is not all it’s cracked up to be, at least not absolutely,” she said, noting that among the oldest old, being a bit overweight actually reduced the risk of dying.

“Being thin is not good as you get older,” she said. “Being underweight at 90 is worse than being underweight at 80 which is worse than being underweight at 70…. Actually the best mortality experience is individuals who gain about five pounds in a decade.”

As for exercise, the study found that more is better, but only up to a point. Those who exercised for 15, 30 or 45 minutes a day incrementally improved their chances of living longer, but higher levels of exercise yielded no additional benefit.

“The good news is that doing it three hours a day doesn’t buy you any more than doing it 45 minutes a day,” she said.

With regard to diet, researchers examined vitamins such as A, C and E, antioxidants, calcium and beverages consumed.

“I swear I did not make this up, but I do like these results,” Kawas admitted with a laugh. “In terms of diet, if you are what you eat, wine and coffee are good places to start.”

The 90+ study found that those who drank one or fewer alcoholic beverages per day decreased mortality 9 percent while those who had two or more drinks daily decreased mortality 14 percent. “The entire thing is being driven by wine,” she said. Beer yielded no statistically significant result, nor did hard liquor intake, but wine drinkers appeared to have the longevity advantage.

Likewise for coffee drinkers. Those who had two or more cups of coffee daily had a 10 percent reduction in mortality, she found.

In short: “It is not good to be too thin in later adulthood, it is bad to lose weight and it’s definitely okay to gain weight. You tend to live longer if you have more activities of any kind, whether they be physical or not, and any amount actually confers benefits,” Kawas said.

The study’s clinical pathology facet is yielding the interesting result that the amyloid plaques and tangles found in the brain that are considered to be the hallmarks for diagnosing Alzheimer’s disease do not show a direct relationship to dementia.

While virtually all people have some tangles in their brains by the age of 90, not all have dementia.

The study has found some people with dementia had very few amyloid deposits, while others with high plaque deposits were not demented. “There is no relationship at all between plaque staging and cognitive scores in our sample,” she said. “There is a modest relationship between tangle scores and cognitive scores… but still not as good a relationship as you would imagine.”

And interesting results are arising from a comparison of those with a clinical diagnosis of dementia with the pathology found when their brains were examined after death.

“Overall, what we found is that there’s a lot of overlap in the distribution of pathology in individuals who are demented and those who are not demented and that although some non-demented people have a lot of pathology, all of them have plaques and tangles in the entorhinal cortex and the hippocampus,” she said.

“And half of the demented people, at least so far, either don’t have enough pathology to account for their dementia or else we need to rethink the amount of pathology that is necessary to cause dementia in this age group.”

Kawas’s talk, and her companion Foster lecture, “Factors That Promote Long Life,” are available for downloading by visiting on line and clicking on “Graduate School of Public Health” in the “live webcasts” menu.

—Kimberly K. Barlow

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