179161 Socioeconomic position and C-reactive protein: The role of psychosocial and behavioral factors

Monday, October 27, 2008: 12:35 PM

Kiarri N. Kershaw, MPH , Department of Epidemiology, University of Michigan, Ann Arbor, MI
Brian Mezuk, PhD , Department of Epidemiology and Community Health, Virginia Commonwealth University, Richmond, VA
Darrell L. Hudson, MPH, PhD , Department of Family and Community Medicine, University of California, San Francisco, San Francisco, CA
Jane A. Rafferty, MA , Institute for Social Research, Ann Arbor, MI
Sha Juan Colbert, MPH , Institute for Social Research, Ann Arbor, MI
Kati M. Knight, MS , Survey Research Center, ISR, University of Michigan, Ann Arbor, MI
James S. Jackson, PhD , Survey Research Center, ISR, University of Michigan, Ann Arbor, MI
Background: C-reactive protein (CRP) is a marker of systemic inflammation and a potential risk factor for cardiovascular disease. Psychosocial stressors and circumstances associated with chronic stress, such as low socioeconomic position (SEP), have been associated with elevated CRP. It is unclear what mediates these relationships. Objective: To evaluate the association between SEP and chronic stress, as indicated by CRP, and determine the contribution of potential psychosocial and behavioral mediators of that relationship. Sample: 3202 participants of the 2003-2006 National Health and Nutrition Examination Survey aged 40+. Methods: Serum CRP levels were assayed using latex-enhanced nephelometry. A cut-off of 0.3 mg/dl CRP was used to designate clinically-elevated levels. SEP was measured using $10,000 categorical increments of income. Potential mediators analyzed included body mass index (BMI), smoking, adequacy of emotional support, availability of instrumental support, and exercise. Results: After adjusting for age, gender, and race/ethnicity, there was a significant inverse association between income and elevated CRP (OR: 0.90, 95% CI: 0.86, 0.95). Smoking was the strongest partial mediator, reducing the log-odds of high CRP by 14.1%. Exercise and adequacy of support also attenuated the association (7.9% and 4.7% reductions, respectively). In stratified analyses, BMI was a partial mediator for women only (10.2% reduction vs. 24.0% increase in men). Among women, the strongest partial mediator was exercise (12.4% reduction) while among men it was smoking (15.4% reduction). Conclusions: Although these results do not completely explain the relationship between income and CRP, they provide insight that could help inform targeted disease prevention efforts.

Learning Objectives:
1. Describe the relationship between socioeconomic position and chronic inflammation. 2. Discuss the differential role of various psychosocial and behavioral factors in mediating the association between income and elevated CRP levels. 3. Evaluate whether the impact of specific psychosocial and behavioral factors on risk of elevated CRP differs for men and women

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I ran all the analyses and helped conceptualize the idea for the study.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.

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