Smoking and Chronic Back Pain: Analyses of the German Telephone Health Survey 2003

In modern societies tobacco consumption represents the greatest avoidable risk factor for a large number of serious diseases (1). While the link between smoking and cancer, respiratory disease and cardiac disease has been clearly demonstrated, the international data on the correlation between tobacco consumption and orthopedic disorders are sparse and contradictory (2, 3). To date no clearcut causal relationship between nicotine and back pain has been shown (4). Nevertheless, the deleterious effect of nicotine is undisputed. On the one hand, nicotine consumption leads in the short term to vasoconstriction and in the long term to arteriosclerosis, resulting not only in an inadequate supply of blood to the internal organs but also to deficient nutrition of bone and thus to reduced bone formation (5, 6). Decreased perfusion of structures in and around the spinal column, particularly the intervertebral disks and the muscles of the back, seem to promote degenerative changes (7–9). On the other hand, tobacco smoke contains poisons and carcinogenic substances that lead to increased bone resorption. Almost one third of the German population over 18 years of age are current smokers (25.4% daily, 7.1% occasionally). Including former smokers yields a proportion of almost 60% of people who have smoked at some time in their lives (10). This highlights the importance of continued intensive research into the consequences of smoking, including the previously neglected link between tobacco consumption and back pain. All of the published studies on the relationship beween musculoskeletal symptoms, particularly in the back, and smoking, have serious limitations. The clinical studies have too few cases and too short a study period, and there are no valid studies that take account of both important retrospective data on smoking history and possible confounders or spurious correlations, such as a sedentary lifestyle, manual work, or mental stress (11–15). The epidemiological studies are mostly cross-sectional in design and consider only current consumption: the study population is divided into "smokers" and "non-smokers," usually excluding important longitudinal data on the duration, intensity, and pattern of consumption (11, 14–18, 22). By definition, therefore, the existing cross-sectional studies on the connection between back pain and tobacco consumption cannot demonstrate whether the tobacco consumption started before the back pain (19), or whether the smoking represents a dysfunctional pain management strategy (i.e., a response to the pain). Mental problems and stress often precisely go hand in hand with tobacco consumption and must therefore be taken into consideration as potential confounders. This has not been the case in the studies published to date. In contrast with the earlier studies, this investigation tested the influence of smoking on the risk of developing back pain under consideration of data on mental health in multivariate single and total models by means of logistic regression (13–15). This was intended to exclude, as far as possible, potential interactions between smoking behavior, mental health, and prevalence of back pain. In this way the influence of tobacco consumption on the risk of back pain could be ascribed to smoking behavior, rather than reflecting the indirect influence of mental problems on back pain. This study, conducted at the Robert Koch Institute, includes detailed data on individual smoking history, thus permitting valid conclusions on the influence of the duration and intensity of cigarette consumption on the risk of back pain.