[Smoking is a risk factor for spinal diseases. Hypothesis of the pathomechanism]

Epidemiological studies strongly imply that smoking is a risk factor for back problems. The question arises as to the nature of the underlying pathomechanism. Several theories are currently discussed in the literature: it could be due to "unhealthy" life styles associated with smoking, to a rise in intraabdominal pressure caused by frequent coughing, or to osteoporosis of smokers. All of these hypotheses, however, do not stand up to a critical examination of the experimental evidence. A new theory is, therefore, put forward, claiming that smoking leads to malnutrition of the discs, which in turn renders them more vulnerable to mechanical stress. Malnutrition can be brought about by CO-Hb formation, vasoconstriction, arteriosclerotic vessel wall changes, impairment of fibrinolytic activity and changes in the flow properties of blood, all of which are known effects of smoking. The evidence for these pathomechanisms is discussed. Future studies should test the above hypothesis experimentally.