Association of Pain, Insomnia, and Depression Clusters with Cognition in Older Mexican Americans

TL;DR

This study finds that clusters of pain, insomnia, and depression are linked to worse cognition in older Mexican Americans, with education modifying these effects.

Contribution

The study identifies distinct symptom clusters and their differential impact on cognition, emphasizing the role of education in cognitive decline.

Findings

Three symptom clusters were identified: pain only, pain and depression, and pain, depression, and insomnia.

The pain and depression cluster was associated with worse baseline cognition compared to the pain-only cluster.

Education modified the association, with higher education linked to greater cognitive decline in the pain and depression cluster.

Abstract

Older Mexican Americans—a rapidly growing segment of the U.S. population—experience high rates of co-occurring pain, depression, and insomnia, but data on how these symptom clusters affect their cognition remain limited. We examined patterns of pain-insomnia-depressive symptom clusters and their association with cognitive decline using data from the Hispanic Established Populations for the Epidemiologic Study of the Elderly (2010-2016), a study of older Mexican Americans in the Southwestern United States. Latent class analysis identified clusters based on pain on weight-bearing, depressive symptoms, and insomnia symptoms. Linear mixed-effects models examined the association between different patterns of symptom clusters and cognitive decline, measured by the Mini-Mental State Examination. Three latent classes were identified (n = 935): pain only (66.5%), pain and elevated depressive symptoms, (21.0%), and pain, elevated depressive symptoms, and insomnia (12.5%). The pain and elevated depressive symptoms cluster (β=-3.72, p < 0.001) and the pain, depressive symptoms, and insomnia cluster (β=-2.33, p < 0.001) were associated with worse baseline cognition compared to the pain only cluster. Education was a significant effect modifier: in stratified analyses, similar findings were observed for those with 0 and 1-6 years of education. Among individuals with ≥7 years of education, those in the pain and elevated depressive symptoms cluster had greater cognitive decline over time compared to the pain only cluster (β=-0.65, p = 0.039). Our findings highlight the need for targeted interventions addressing co-occurring conditions to mitigate cognitive decline among older Mexican Americans. Education appears to modify this association, suggesting a role in cognitive reserve and warranting consideration in intervention design.