title: Low socioeconomic status and body mass index as risk factors for inflammation in older adults: conjoint influence on C-reactive protein?
abstract: BACKGROUND
  Low socioeconomic status and high levels of body mass are two risk factors for elevated C-reactive protein, a biomeasure signifying inflammation. Though past research identifies the additive effect of these particular risk factors, this study examines their interactive effects to uncover whether body mass index exacerbates or levels the detrimental consequences of occupying a disadvantaged social position.
  
  
  METHODS
  This study employs a representative survey of American adults, aged 57-84 years, using self-reported and laboratory measures. Additive and multiplicative linear regression models are used to analyze logged C-reactive protein levels (mg/l) drawn from assayed blood samples.
  
  
  RESULTS
  Significant negative interactions were observed between body mass index and two indicators of low socioeconomic status on C-reactive protein, reflecting a cross-over effect.
  
  
  CONCLUSIONS
  The results demonstrated the importance of a multiplicative model for studying risk factor accumulation and identify low socioeconomic status as an early and primary risk factor for elevated C-reactive protein.
authors.affiliation: Center on Aging and the Life Course, Purdue University, 155 South Grant Street, West Lafayette, IN 47907-2114, USA. mhschafe@purdue.edu
authors.forename: Markus H
authors.initials: MH
authors.lastname: Schafer
authors.forename: Kenneth F
authors.initials: KF
authors.lastname: Ferraro
authors.forename: Sharon R
authors.initials: SR
authors.lastname: Williams
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000032:analysis*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007249:Inflammation / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012923:Social Class
chemical_list: D002097:C-Reactive Protein