An index of the ratio of inflammatory to antiviral cell types mediates the effects of social adversity and age on chronic illness

Ronald L Simons; Man-Kit Lei; Steven R.H Beach; Ashley B Barr; Carolyn E Cutrona; Frederick X Gibbons; Robert A Philibert

doi:10.1016/j.socscimed.2017.03.005

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An index of the ratio of inflammatory to antiviral cell types mediates the effects of social adversity and age on chronic illness

Journal article

Peer reviewed

An index of the ratio of inflammatory to antiviral cell types mediates the effects of social adversity and age on chronic illness

Ronald L Simons, Man-Kit Lei, Steven R.H Beach, Ashley B Barr, Carolyn E Cutrona, Frederick X Gibbons and Robert A Philibert

Social science & medicine (1982), Vol.185, pp.158-165

07/2017

DOI: 10.1016/j.socscimed.2017.03.005

PMID: 28356188

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Abstract

It is assumed that both social stress and chronological age increase the risk of chronic illness, in part, through their effect on systemic inflammation. Unfortunately, observational studies usually employ single-marker measures of inflammation (e.g., Interleukin-6, C-reactive protein) that preclude strong tests for mediational effects. The present study investigated the extent to which the effects of socioeconomic disadvantage and age on onset of chronic illness is mediated by dominance of the innate (inflammatory) over the acquired (antiviral) components of the immune system. We assessed inflammation using the ratio of inflammatory to antiviral cell types (ITACT Ratio). This approach provided a stronger test of evolutionary arguments regarding the effect of social stress on chronic inflammation than is the case with cytokine measures, and afforded an opportunity to replicate findings obtained utilizing mRNA. We used structural equation modeling and longitudinal data from a sample of 100 middle-age African American women to perform our analyses. Dominance of inflammatory over antiviral cell activity was associated with each of the eight illnesses included in our chronic illness measure. Both socioeconomic disadvantage and age were also associated with inflammatory dominance. Pursuant to the central focus of the study, the effects of socioeconomic adversity and age on increased illness were mediated by our measure of inflammatory dominance. The indirect effect of these variables through inflammatory cell profile was significant, with neither socioeconomic disadvantage nor age showing a significant association with illness once the impact of inflammatory cell profile was taken into account. First, the analysis provides preliminary validation of a new measure of inflammation that is calculated based on the ratio of inflammatory to antiviral white blood cells. Second, our results support the hypothesis that socioeconomic disadvantage and chronological age increase risk for chronic illness in part through their effect on inflammatory processes. •Inflammation is assumed to mediate the effect of adversity on chronic illness.•We calculated an index of inflammation based on the distribution of immune cell types.•This index mediated the effect of both social adversity and age on chronic illness.

Chronic illness

Social determinants of health

Inflammation

Socioeconomic adversity

Accelerated aging

Details

Title: Subtitle: An index of the ratio of inflammatory to antiviral cell types mediates the effects of social adversity and age on chronic illness
Creators: Ronald L Simons - Department of Sociology, University of Georgia, 324 Baldwin Hall, Athens, GA 30606, United States
Man-Kit Lei - Center for Family Research, University of Georgia, 1095 College Station Road, Athens, GA 30605, United States
Steven R.H Beach - Department of Psychology, University of Georgia, 157 IBR Psychology Building, Athens, GA 30602, United States
Ashley B Barr - Department of Sociology, SUNY Buffalo, 430 Park Hall, Buffalo, NY 14260, United States
Carolyn E Cutrona - Department of Psychology, Iowa State University, W112 Lagomarcino Hall, Ames, IA 50011, United States
Frederick X Gibbons - Department of Psychological Sciences, University of Connecticut, 406 Babbidge Road, Storrs, CT 06269, United States
Robert A Philibert - Department of Psychiatry, University of Iowa, 2-126B Medical Education Building, Iowa City, IA 52242, United States
Resource Type: Journal article
Publication Details: Social science & medicine (1982), Vol.185, pp.158-165
DOI: 10.1016/j.socscimed.2017.03.005
PMID: 28356188
NLM abbreviation: Soc Sci Med
ISSN: 0277-9536
eISSN: 1873-5347
Publisher: Elsevier Ltd
Grant note: DOI: 10.13039/100000050, name: National Heart, Lung, and Blood Institute, award: HL118045; DOI: 10.13039/100000026, name: National Institute on Drug Abuse, award: R21DA034457; DOI: 10.13039/100000025, name: National Institute of Mental Health, award: R01MH62699, R01MH62666
Language: English
Date published: 07/2017
Academic Unit: Roy J. Carver Department of Biomedical Engineering; Psychiatry; Iowa Neuroscience Institute
Record Identifier: 9984003947602771

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