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The 90+ Study

When medical students do their first rotation in paediatrics, they are told that children are not small adults. They are a different species! Children respond differently to diet and drugs than adults. Now we are learning that the same situation may prevail for those over the age of 90. They too are a different species. And they are the fastest growing segment of the North American population. Thanks to the ongoing 90+ Study headed by Dr. Claudia Kawas of the University of California, these nonagenarians are set to teach us about aging in a healthy fashion. It all started back in 1981 when some 14,000 residents of a retirement community then known as "Leisure World" in California filled out detailed questionnaires about their diet, activities, vitamin intake, and medical history. About twenty years later Dr. Kawas and her staff obtained a $6 million grant from the National Institutes of Health to track how the subjects who had filled out the questionnaires had fared. They managed to find some 1600 who had made it past the age of 90 and enrolled them in a study whereby they would be given physical examinations and cognitive tests every six months. The goal was to tease out information about what factors contributed to their longevity.

Some of the data they crunched was not surprising. Smoking obviously shortened life expectancy. Over 40% of people aged 90 and older suffer from dementia while almost 80% are disabled, both conditions being more common in women than men. As little as 15 minutes of exercise a day on average made a difference, with 45 minutes being optimal. Exercising more did not afford a greater benefit. Keeping active in non-physical ways, such as socializing, playing board games, and attending book clubs, also was associated with longer life. So was alcohol intake. People who drank up to two drinks per day lived longer than non-drinkers. There was nothing special about red wine, any type of alcohol had the same effect. Moderate amounts of coffee were also linked with longevity. But there were some surprising findings. Taking dietary supplements, whether vitamins or calcium supplements, did not increase longevity. Weight, however did. Not in an expected fashion though. Skinnyness was not good, people who were overweight in their 70s lived longer than normal or underweight people.

Perhaps the most surprising finding was that  40 percent of the time, what seemed to be Alzheimer's disease in people over 90 actually wasn't. Participants in the study agreed to donate their brains for research after their demise and the researchers found that many showed evidence of microscopic strokes rather than the characteristic plaques and neurofibrially tangles associated with Alzheimers disease. What caused these strokes remains a mystery but paradoxically they were more likely to be found in subjects who had low blood pressure. People in their 90s may have clogged and narrow blood vessels and may have the problem of not getting enough blood through the vessels to the brain. If blood pressure is too low, it could cause mini strokes due to a lack of oxygen and that can cause deterioration of brain tissue. Another example of the fact that nonagenarians are not just “old adults.”

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