Relations of C-Reactive Protein and Obesity to the Prevalence and the Odds of Reporting Low Back Pain

Objective: To assess the odds of reporting low back pain (LBP) as related to systemic inflammation and obesity. Design: Cross-sectional analysis of the 1999 to 2004 National Health and Nutrition Examination Survey (NHANES). Setting: National database analysis. Participants: Population-based sample of 15,322 participants in the 1999 to 2004 NHANES databases. Interventions: Not applicable. Main Outcome Measures: Systemic inflammation was measured by C-reactive protein (CRP) and fibrinogen. Obesity was quantified by body mass index and waist circumference (WC). LBP was identified by self-report. Analysis included logistic regression to assess the odds of reporting LBP as related to systemic inflammation and obesity. Results: It was hypothesized that obesity and systemic inflammation would increase the odds of reporting LBP. Participants with elevated CRP (>3.0mg/dL) had 1.74 (95% confidence interval [CI], 1.04-2.91) greater odds of reporting LBP. Those who were obese (>= 30kg/m(2)) with elevated CRP had 2.87 (95% CI, 1.18-6.96) greater odds of reporting LBP than those without elevated CRP. When using WC as the measure of obesity, participants with high WC values had significantly greater odds of reporting LBP (odds ratio=2.39; 95% CI, 1.09-5.21). Conclusions: To our knowledge, this is the first study showing that high levels of CRP may increase the odds of reporting LBP, especially in those who are obese. These findings warrant further investigation of the interrelations among obesity, systemic inflammation, and LBP. Archives of Physical Medicine and Rehabilitation 2013;94:745-52 (C) 2013 by the American Congress of Rehabilitation Medicine