Different loneliness types, cognitive function, and brain structure in midlife: Findings from the Framingham Heart...

Area of Science:

• Neuroscience
• Gerontology
• Psychiatry

Background:

• The relationship between persistent loneliness and brain structures linked to cognitive decline and Alzheimer's disease (AD) is not fully understood.
• Midlife loneliness may represent a critical period for investigating its impact on brain health and cognitive trajectories.

Purpose of the Study:

• To investigate the associations between different types of loneliness, cognitive performance, and regional brain volumes.
• To determine if persistent loneliness impacts brain structures relevant to cognitive aging and AD risk.

Main Methods:

• Longitudinal assessment of loneliness using the Center for Epidemiologic Studies Depression Scale in the Framingham Heart Study, Generation 3.
• Robust regression models analyzed associations between loneliness, neuropsychological performance (n=2,609), and MRI brain data (n=1,829) from 2002-2019.
• Analyses were stratified by sex, depression status, and Apolipoprotein E4 (ApoE4) genotype.

Main Results:

• Persistent loneliness, unlike transient loneliness, was significantly associated with cognitive decline, particularly in memory and executive functions.
• Persistent loneliness correlated with reduced temporal lobe volume. In women, it was linked to smaller frontal lobe, temporal lobe, and hippocampus volumes, and larger lateral ventricle volumes.
• Higher cumulative loneliness scores were associated with smaller parietal, temporal, and hippocampus volumes and larger lateral ventricles, especially in individuals with the ApoE4 genotype.

Conclusions:

• Persistent midlife loneliness is associated with brain atrophy in regions critical for memory and executive functions.
• Interventions targeting the chronicity of loneliness may help mitigate the risk of age-related cognitive decline and Alzheimer's disease.