# Does type or diversity of activities delay aging-related cognitive decline?

## TL;DR

This study explores how different types and amounts of activities affect cognitive decline in midlife and late life, finding that activity diversity and timing are important.

## Contribution

The study provides new insights into how activity type and timing influence cognitive decline across different life stages.

## Key findings

- Activity diversity slows midlife cognitive decline, while frequent cognitive activities reduce late-life decline.
- Social contact frequency is linked to slower midlife decline, and social group participation is more impactful in late life.
- Physical activity had little effect on cognitive decline in the studied age range.

## Abstract

Research has shown a correlation between engagement in activities and late-life cognition, but cross-sectional associations are likely to be inflated by reverse causality. This study investigated the prospective effects of activity engagement—frequency of and diversity across activity types—on aging-related cognitive decline.

Using data from the Health and Retirement Study (HRS) and Midlife in the United States (MIDUS) study, we evaluated whether baseline measures of 4 activity types (cognitive, physical, contact with family/friends, and social group participation) predicted subsequent cognitive decline adjusted for potential confounders. We compared the effects of activity type frequency with the effect of activity diversity.

In HRS, activity diversity was associated with slower midlife (ages 55-65) cognitive decline, whereas more frequent cognitive activities yielded the largest reduction in late-life (ages 65-85) cognitive decline. Frequency of social contact was associated with slower midlife cognitive decline, whereas more frequent social group participation had a stronger association in later life. Physical activity did not significantly affect the cognitive decline trajectory. In MIDUS, neither the activity frequency nor diversity was associated with subsequent cognitive decline.

Our results underscore that both type and timing of activity matter: Efforts to promote activity diversity and social contact are likely to be most effective in midlife, whereas cognitive activities and social group participation may be more impactful in late life. Physical activity alone had little effect on mid-to-late-life cognition but may be valuable earlier in life and in the context of activity diversity.