Overview
- Researchers analyzed 137,653 cognitive assessments from 30,421 participants in the U.S. Health and Retirement Study spanning 2004–2018.
- Using a counterfactual g-formula approach, they estimated a direct causal effect of objective isolation on faster decline rather than a mere association.
- Only about 6% of the isolation effect operated through loneliness, showing that the two factors influence cognition independently.
- Simulated interventions suggested that lowering isolation would raise average cognitive scores by about 0.19 points on a 0–27 scale, with targeting people who live alone capturing roughly half the population-wide benefit.
- Protective effects appeared across gender, race and education groups, underscoring calls from the authors to make regular social contact for older adults a public-health priority.