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.