Adding to the growing evidence that social activity helps prevent age-related cognitive decline, a longitudinal study involving 1,138 older adults (mean age 80) has found that those who had the highest levels of social activity (top 10%) experienced only a quarter of the rate of cognitive decline experienced by the least socially active individuals (bottom 10%). The participants were followed for up to 12 years (mean of 5 years).

Social activity was measured using a questionnaire that asked participants whether, and how often, in the previous year they had engaged in activities that involve social interaction—for example, whether they went to restaurants, sporting events or the teletract (off-track betting) or played bingo; went on day trips or overnight trips; did volunteer work; visited relatives or friends; participated in groups such as the Knights of Columbus; or attended religious services.

Analysis adjusted for age, sex, education, race, social network size, depression, chronic conditions, disability, neuroticism, extraversion, cognitive activity, and physical activity.

There has been debate over whether the association between social activity and cognitive decline is because inactivity leads to impairment, or because impairment leads to inactivity. This study attempted to solve this riddle. Participants were evaluated yearly, and analysis indicates that the inactivity precedes decline, rather than the other way around. Of course, it’s still possible that there are factors common to both that affect social engagement before showing up in a cognitive test. But even in such a case, it seems likely that social inactivity increases the rate of cognitive decline.