Loneliness in Middle Age: Biomarkers of Cardiometabolic Health and the Influence of Perceived Neighborhood Quality
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Date
2017-05-01
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Johns Hopkins University
Abstract
Problem Statement
Loneliness is an emotional state of perceived lack of positive relationships that increases odds of death, particularly among middle-aged adults. Inflammation contributing to cardiovascular disease may drive poor outcomes. Molecular level studies show loneliness influences the inflammatory response, but clinical studies of inflammatory biomarkers and loneliness are inconsistent. Loneliness is linked to cardiometabolic function through higher blood pressure, lack of regular exercise, and poor sleep quality. However, studies examining loneliness and metabolic syndrome drew different conclusions. Therefore, we examined relationships between loneliness and systemic inflammation and metabolic syndrome. Also, research among European older adults demonstrated that living conditions and social integration influence loneliness, but it is not clear if these factors influence loneliness in middle-aged US adults.
Methods
This is a secondary analysis of the Biomarker Project, a special study of Midlife in the US (MIDUS). Baseline MIDUS data was collected from 1995-1996 (N=7,108) and a follow-up survey was conducted from 2004-2006 (N=4,963). A sample of African Americans from Milwaukee was surveyed in 2005-2006 (N=592). The Biomarker Project enrolled participants from the MIDUS baseline and Milwaukee samples. Data were collected from 2004-2009 (N=1,255). Our sample includes Biomarker Project participants age 35-64 years (n=927). Controlling for potential confounders, we conducted multivariable linear regression to test whether feeling lonely is associated with higher levels of inflammatory biomarkers, and we conducted multivariable logistic regression to test whether feeling lonely is associated with metabolic syndrome and its individual criteria. With loneliness as the dependent variable, we also tested its association with perceived neighborhood quality and if social integration mediates the relationship.
Results
After adjustment, feeling lonely was: positively associated with higher interleukin-6, fibrinogen, and C-reactive protein values; and not associated with metabolic syndrome or its criteria. Perceived neighborhood quality was associated with loneliness after adjustment, and social integration partially mediated the relationship.
Conclusions
The results provide evidence for an association between feeling lonely and systemic inflammation implicated in development of cardiovascular disease among middle-aged US adults. And neighborhood factors and social integration influence the development of loneliness. Loneliness interventions at individual and community levels may improve psychosocial well-being, health outcomes, and survival.
Advisor: Sarah L. Szanton, PhD, ANP, FAAN
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Keywords
loneliness, middle age, systemic inflammation, metabolic syndrome, neighborhood quality, social integration