Associations Between Low Back Pain and Muscle-strengthening Activity in U.S. Adults

Study Design. This was a cross-sectional study. Objective. The primary aim of the study was to examine the association between low back pain (LBP) and muscle-strengthening activity (MSA) among U.S. adults using gender-stratified analyses. Summary of Background Data. LBP is a common medical condition that impacts quality of life and professional productivity and increases the financial burden on the health care system by augmenting medical treatment costs. Previous studies analyzing gender-dependent relationships between MSA and LBP have produced mixed results. Methods. Our sample included 12,721 participants from the 1999 to 2004 National Health and Nutrition Examination Survey (NHANES). Participants were categorized into one of three levels of self-reported MSA: no MSA, insufficient MSA (1 day/wk), or meeting the 2008 Department of Health and Human Services (DHHS) recommendation for MSA (≥2 days/wk). Results. Gender-stratified analyses revealed significantly lower odds of reporting LBP among women [odds ratio (OR) 0.82, 95% confidence interval (CI) 0.70–0.96, P = 0.03] and men (OR 0.86; 95% CI 0.70–0.96, P = 0.01) who reported amounts of MSA that met the DHHS recommendation compared with those reporting no MSA. Following adjustment for smoking status, the odds remained significant among women ( P = 0.03) but not among men ( P = 0.21). Conclusion. These findings indicate that engaging in MSA at least 2 days/wk is associated with lower odds of LBP and that smoking may be an important mediating factor that should be considered in future LBP research. Level of Evidence: 4