Comparison of the prevalence of low back pain and related spinal diseases among smokers and nonsmokers: Using Korean national health insurance database

Background: To compare the risk of low back pain (LBP) and related spinal diseases between smokers (exposure group) and nonsmokers (non-exposure group). No large registry study has so far investigated the association between smoking and LBP-related spinal diseases such as intervertebral disc disease, spinal stenosis, spinal instability, and spondylolisthesis. Methods: A random sample was taken from the Korean National Health Insurance Research Database. In total, 204,066 men (160,105 smokers, 43,961 nonsmokers) who were followed up between 2002 and 2013 were included in the analysis. Patients with previous back pain or spinal disease in 2003 and 2004, patients with inappropriate data, and women (due to the lower percentage of smokers) were excluded. The Cox proportional hazard model was used to investigate the risk of LBP and related spinal diseases associated with smoking, while adjusting for demographic, clinical, and socioeconomic factors. Results: The overall median follow-up period was 5.6 years (interquartile range, 3.48–8.43 years). Compared to the nonsmoker group, the smoker group had a higher incidence of LBP (p = 0.01), intervertebral disc disease (p < 0.001), spinal stenosis (p = 0.004), spinal instability (p < 0.001), and spondylolisthesis (p = 0.023). Compared to the nonsmoker group, the smoker group had a higher adjusted hazard ratio (HR) per year of LBP (HR, 1.18; 95% confidence interval [CI], 1.15 to 1.21), intervertebral disc disease (HR, 1.25; 95% CI, 1.21 to 1.30), spinal stenosis (HR, 1.52; 95% CI, 1.41 to 1.64), spinal instability (HR, 1.33; 95% CI, 1.24 to 1.44), and spon-dylolisthesis (HR, 1.49; 95% CI, 1.23 to 1.80). Conclusions: Smokers in male samples were at higher risk for LBP and related spinal diseases than nonsmokers.