title: Mediation analysis of relationships between chronic inflammation and quality of life in older adults.
abstract: BACKGROUND
  This article summarizes exploratory analyses of relationships between chronic inflammation, its physical consequences, and quality of life (QoL). It summarizes key findings from preliminary analyses, and contextualizes these results with extant sociomedical literature to recommend directions for future research.
  
  
  METHODS
  Cross-sectional data from the National Social Life, Health, and Aging Project (NSHAP) were used to explore these relationships. Inflammation was assessed via the biomarker C-reactive protein (CRP). We examined associations between CRP levels and two different domains of QoL: happiness with life in general and happiness with intimate relationships. We used ordinal logistic regression with companion OLS models and Sobel-Goodman tests to assess potential mediation, and also conducted a variety of sensitivity analyses.
  
  
  RESULTS
  Findings suggest that mediation pathways for the overall association between chronic inflammation and QoL may differ markedly across particular outcome constructs. Specifically, it shows mediation potential for the clinical sequelae of chronic inflammation in frameworks using happiness as an outcome measure, but not in those using relationship satisfaction. Disability appears to mediate the effect of inflammation by 27 %; chronic pain appears to exert a similar mediation effect of 21 %.
  
  
  CONCLUSIONS
  Pain and disability linked to chronic inflammation appear to play a small but significant mediating role in the overall reduction in QoL observed among older adults with biomarker evidence of chronic inflammation. We note that these patterns are best framed as dynamic elements of a complex causal fabric, rather than powerful determinants that override other factors contributing to QoL. Hypotheses for further exploration using longitudinal data from the NSHAP are thus offered, pending availability of Wave III data in future years.
authors.affiliation: Department of Behavioral Sciences and Social Medicine, College of Medicine, Florida State University, 1115 West Call Street, Suite 3200, Tallahassee, FL, 32306-4300, USA. xnowakowski@fsu.edu.
authors.forename: Alexandra C H
authors.identifier: http://orcid.org/0000-0002-9072-2482
authors.initials: AC
authors.lastname: Nowakowski
authors.affiliation: Department of Sociology, College of Social Sciences and Public Policy, Florida State University, Tallahassee, FL, 32306, USA.
authors.forename: Katelyn Y
authors.initials: KY
authors.lastname: Graves
authors.affiliation: Department of Sociology, College of Social Sciences, Mathematics, and Education, University of Tampa, Tampa, FL, 33606, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Sumerau
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000523:psychology*; D059350:Chronic Pain / Q000523:psychology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007249:Inflammation / Q000523:psychology*; D008297:Male; D008875:Middle Aged; D011788:Quality of Life / Q000523:psychology*; D014481:United States
keywords: Elaboration modeling; Inflammation; Logistic regression; NSHAP; Quality of life