Who doesn't every elderly person have a cognitive function decline as they age?   Elderly people who exercise at least once a week, have at least a high school education and a ninth grade literacy level, are not smokers and are more socially active are correlated to maintained cognitive skills through their 70s and 80s, according to research published in the June 9, 2009, print issue of Neurology.

The study followed 2,500 people age 70 to 79 for eight years, testing their cognitive skills several times over the years. Many of the participants showed decline in cognitive function. Fifty-three percent of the participants showed normal age-related decline and 16 percent showed major cognitive decline. However, 30 percent of the participants had no change or improved on the tests over the years.

The researchers then examined what factors made the people whose cognition stayed sharp different from those who lost some of their abilities over eight years.

"To this day, the majority of past research has focused on factors that put people at greater risk to lose their cognitive skills over time, but much less is known about what factors help people maintain their skills," said study author Alexandra Fiocco, PhD, of the University of California, San Francisco.

The study reported a unique profile that differentiates people who maintain cognitive function from people who show age-related decline: people who exercise moderately to vigorously at least once a week are 30 percent more likely to maintain their cognitive function than those who do not exercise that often. Those who have at least a high school education are nearly three times as likely to stay sharp as those who have less education. Elderly with a ninth grade literacy level or higher are nearly five times as likely to stay sharp than those with lower literacy levels. Non-smokers are nearly twice as likely to stay sharp as those who smoke. Finally, people working or volunteering and people who report living with someone are 24 percent more likely to maintain cognitive function in late life.

"Some of these factors such as exercise and smoking are behaviors that people can change. Discovering factors associated with cognitive maintenance may be very useful in prevention strategies that guard against or slow the onset of dementia," Fiocco said. "These results will also help us understand the mechanisms that are involved in successful aging."

The study was supported by the National Institutes of Health.