More friends = better memory

Lots of friendships may be a hedge against the memory loss associated with aging, a new Harvard study finds.

Over the six years of the study, people with the most social ties saw their memory decline at less than half the rate of people with the fewest social connections. Social activity appeared to be a particularly strong buffer against memory decline in two groups: people with less than a high school education and people who had vascular conditions such as high blood pressure, diabetes, or stroke.

More than 16,000 people over age 50 were tested four times from 1998 through 2004. Each time, participants were scored on five aspects of their social lives: marital status, volunteer activities, and contact with parents, children, and neighbors. To asses their memory, they were asked to recall a list of 10 common words five minutes after they first heard them and after another unrelated conversation. The participants also answered questions about their physical and mental health.

To account for the possibility that failing memory might be causing shrinking social activity, the researchers, including Karen A. Ertel of the Harvard School of Public Health, took out results from the 25 percent of people with the lowest scores on social contacts and analyzed the remaining data. The conclusions still held up, even when they tested their hypothesis further by going back to memory scores taken in 1993.

"Our results suggest that increasing social integration may be an important component of efforts to protect older Americans from memory decline," the authors write in the American Journal of Public Health.