Social connection and cognitive health: A review of concepts, measures, and research priorities.

Lack of social connection is a major risk factor for Alzheimer's disease and related dementias, on a par with other common risk factors like physical inactivity and smoking. Yet we still know surprisingly little about how social connection affects cognitive health. Our review provides updated guidance for researchers interested in testing new mechanistic models of social connection and cognitive health over the life course. First, we conceptualize social connection and its various components. Second, we provide readers with a supplemental compendium of social connection measures and discuss how to tailor different types of measures to specific research goals. Third, we advance a conceptual model linking social connection to cognitive health across different social, spatial, and temporal contexts, while also considering potential sources of confounding and reciprocal causation. Finally, we outline five priority areas for future research into social connection and cognitive health across the life course.