The Association Between Self-Reported Cigarette Smoking and Spinal Pain is Not Explained by Serum Cotinine Levels.

PURPOSE: The aim of this study was to check if self-reported smoking is still associated with back pain above and beyond its association with cotinine, to test the hypothesis that the association of self-reported cigarette smoking with back pain is due to residual confounding.

METHODS

Secondary analyses of population-based cross-sectional data pertaining to 4470 adults were conducted. In multivariate analyses examining the associations of self-reported smoking with several spinal pain outcomes (neck pain, low back pain, low back pain with pain below knee, self-reported diagnosis of arthritis/rheumatism, and related limitations), further adjustment for serum cotinine concentrations was made.

RESULTS

Self-reported cigarette smoking was associated with neck pain (adjusted Odds Ratio (aOR) Regular smokers vs. Non-smokers: 1.44; 95% Confidence Interval (CI): 1.14-1.82), low back pain (aOR: 1.48; 95% CI: 1.24-1.78), low back pain with pain below knee (aOR: 1.98; 95% CI: 1.42-2.76), as well as arthritis/rheumatism (aOR: 1.33; 95% CI: 1.03-1.71), and related functional limitations (P < .05). Further adjustment for serum cotinine concentrations brought about little change in the ORs or beta coefficients.

CONCLUSIONS

These results do not support the hypothesis that serum cotinine concentrations explain the well-known relationship between cigarette smoking and spinal pain.