Structural social factors modify the association between Alzheimer's pathology and cognitive function

Area of Science:

• Neuroscience
• Gerontology
• Social Science

Background:

• Social factors are increasingly recognized for their influence on cognitive decline and dementia risk.
• However, the specific interplay between social structures and Alzheimer's disease (AD) pathology concerning cognitive function remains underexplored.

Purpose of the Study:

• To investigate how structural social factors, specifically relationship status (RS) and living situation (LS), modulate the association between AD pathology and cognitive performance.
• To determine if social context alters the impact of AD pathology on cognition.

Main Methods:

• Analysis of observational cohort data from the National Alzheimer's Coordinating Center (NACC) and the Imaging Dementia-Evidence for Amyloid Scanning (IDEAS) study.
• Cognitive performance assessed using the Mini-Mental State Examination (MMSE).
• AD pathology evaluated via postmortem neuropathology reports or amyloid PET scans; RS and LS data were analyzed using group comparisons and regression models to test for interactions with AD pathology.

Main Results:

• A significant proportion of participants were single (up to 31%) or lived alone (up to 22%).
• Individuals in a relationship (RS+) or living with others (LS+) exhibited poorer cognitive performance (MMSE scores) at equivalent levels of AD pathology compared to their counterparts (RS- or LS-).
• Living situation (LS) modified the AD pathology-cognition relationship, with those living with someone (LS+) showing lower MMSE scores, particularly if the cohabitant was not a partner. Relationship status (RS) in the NACC cohort showed that being in a relationship (RS+) was associated with lower overall MMSE scores and a weaker association between AD pathology and cognition.

Conclusions:

• Both living situation and relationship status influence how Alzheimer's disease pathology relates to global cognitive status.
• Being in a relationship appeared to buffer the cognitive effects of AD pathology, while living with someone was linked to lower cognitive status irrespective of pathology levels.
• The findings highlight that the relationship between AD pathology and cognitive outcomes can be context-dependent, varying across different social structures, though the causal direction requires further investigation.