Objective: C-reactive protein (CRP) is emerging as an important predictor of cardiovascular disease (CVD), and chronic inflammation may be a mechanism through which stress affects disease risk. We investigated the contribution of behavioral and psychosocial factors to variation in CRP concentrations in a population-based sample of middle-aged and older adults.
Methods: A high sensitivity enzyme-linked immunosorbent assay (ELISA) validated for use with dried blood spot samples was used to determine CRP concentrations in a representative sample of 188 52- to 70-year-olds. Demographic (gender, ethnicity, socioeconomic status), anthropometric (height, weight, waist circumference, percent body fat), behavioral (alcohol consumption, smoking, sleep quality, dietary quality), and psychosocial data (perceived stress, chronic stress, depressive symptoms, loneliness, perceived social support) were collected on the same day as blood samples. Psychosocial variables collected the year before were also used to investigate the impact of changing psychosocial environments. Log-transformed CRP concentrations were examined in a series of nested multivariate regression models.
Results: African American and female participants were found to have higher CRP concentrations, as did individuals with lower levels of education. However, ethnic differences disappeared after the addition of behavioral and psychosocial variables. Waist circumference, latency to sleep, smoking, and perceived stress were independently associated with increased concentrations of CRP.
Conclusions: Psychosocial stress, as well as health behaviors, are important predictors of inflammatory activity in a population-based sample and should be considered in future research on inflammation and CVD.
BMI = body mass index; CRP = C-reactive protein; CVD = cardiovascular disease; ISEL = Interpersonal Support Evaluation List; PSS = Perceived Stress Scale.
From the Department of Anthropology, Northwestern University, Evanston, Illinois (T.W.M.); Cells to Society (C2S): Center on Social Disparities and Health, Institute for Policy Research, Northwestern University, Evanston, Illinois (T.W.M.); Chicago Center for Cognitive and Social Neuroscience, University of Chicago, Chicago, Illinois (L.C.H., J.T.C.); Department of Psychology, University of Chicago, Chicago, Illinois (L.C.H., J.T.C.).
Address correspondence and reprint requests to Thomas McDade, PhD, Northwestern University, Department of Anthropology, 1810 Hinman Avenue, Evanston, IL 60208-1310. E-mail: firstname.lastname@example.org
Received for publication August 12, 2005; revision received December 8, 2005.
This research was supported by National Institute on Aging Program Grant PO1 AG-18911.