The association between tobacco smoking and surgical intervention for lumbar spinal stenosis: cohort study of 331,941 workers.

BACKGROUND CONTEXT: Tobacco smoking is an injurious habit associated with a number of chronic disorders. Its influence on disc metabolism and degeneration including lumbar spinal stenosis (LSS) has been investigated in the literature.

PURPOSE: We aimed to investigate whether tobacco smoking is an independent risk factor for undergoing surgical intervention for LSS.

STUDY DESIGN/SETTING: This is a prospective cohort study.

PATIENT SAMPLE: The patient sample of 331,941 workers was derived from a Swedish nationwide occupational surveillance program for construction workers.

OUTCOME MEASURE: The outcome measure included the incidence of undergoing surgical intervention for LSS in tobacco smokers versus no smokers.

MATERIALS AND METHODS: At inclusion, age, sex, body mass index (BMI), workers' job title, and self-reported smoking habits were registered. The workers were divided into four categories: never smoked, former smoker, moderate current (1-14 cigarettes/day), and heavy current (≥15 cigarettes/day). Patients who underwent a surgically treated LSS were defined using the relevant International Classification of Diseases (ICD) disease code derived from the Swedish National Patient Register.

RESULTS: A total of 331,941 participants were included in the analysis. Forty-four percent of the participants were non-smokers, 16% were former smokers, 26% were moderate smokers, and 14% were heavy smokers. The vast majority of construction workers were males (95%). During the average follow-up of 30.7 years, 1,623 participants were surgically treated for LSS. The incidence rate ratio (IRRs) of LSS varied across smoking categories, with the highest values found in heavy smokers. Compared with non-smokers, all smoking categories show an increased incidence of surgically treated LSS. The findings were consistent even when the comparison was performed for participants with BMIs between 18.5 and 25 and for participants aged between 40 and 74 years.

CONCLUSIONS: Tobacco smoking is associated with an increased incidence of surgically treated LSS. The effect seems to be dose related, whereby heavy smokers have a higher risk than moderate or former smokers.