The association between active and passive smoking and frequent pain in a general population

Abstract

Background: It is controversial whether the association between back pain, and other types of chronic pain, and smoking is causal or not.

Aim: To examine the relationship between frequent pain and smoking, and between frequent pain and exposure to environmental tobacco smoke (ETS) in smokers and non-smokers.

Methods: A randomised population-based study, Inter99 (1999-2006), Denmark. Subjects in the intervention groups (N=6784; participation rate=52.5%) completed self-report questionnaires. Cross-sectional data from baseline were analysed in adjusted logistic regression analyses to investigate the relationship between active and passive smoking and frequent pain in the back, abdomen, joints and head.

Results: Daily smokers reported significantly more frequent pain in every of the six locations, and in several, minimum three, locations (OR=1.98 (95%CI=1.6-2.4)) than never smokers. We found a dose-response relationship between frequent pain and intensity of both active and passive smoking (test-for-trend p<0.001). Those exposed to 5h or more of ETS reported significantly more frequent pain than those almost never exposed to ETS (non-smokers: OR=1.46 (95%CI=1.2-1.8), and smokers: OR=2.04(95%CI=1.4-3.0)). Also, an earlier smoking debut and an increasing number of pack-years increased the probability of frequent pain in daily smokers (test-for-trend p<0.05).

Conclusion: We found significant association, dose-response and reversibility between active smoking and frequent pain in all six locations. Furthermore, we found that increasing intensity of ETS increased the probability of frequent pain in non-smokers, which has not been shown before. In conclusion, several findings in this study indicate a causal link between tobacco smoke and pain, which is supported by recent prospective studies.