Many Lower Back Problems a Consequence of Body Shape -- Except Among Smokers

From the WebMD Archives

Dec. 28, 1999 (Atlanta) -- Personal characteristics are most often to blame for lower back pain, rather than strenuous labor, concludes a new study from the United Kingdom. However, another new study, this one from Canada, shows that at least one physical act can cause lower back pain, especially in adolescents: lifting a cigarette. Both studies appear in the December issue of the journal Spine.

In the first study, researchers from the University of Bristol in the United Kingdom and the Schulthess Clinic in Zurich, Switzerland studied 400 health care workers. None of the volunteers suffered from serious back pain causing them to miss work or seek medical attention. The volunteers completed questionnaires and underwent a thorough physical examination and test. The subjects' spines and hips were examined for curvature and mobility. Also, their legs and backs were tested for strength. The volunteers then completed six follow-up questionnaires over the next 3 years.

According to lead researcher Michael Adams, PhD, personal risk factors accounted for only 12% of low back pain. "We found that certain physical factors -- a long, stiff, and flat lumbar spine -- are better predictors of first-time 'severe' low back pain than the psycho-social factors studied," Adams tells WebMD.

The study confirms previous research in many respects, but it also breaks new ground. Adams tells WebMD that the study shows for the first time that a stiff back (low range of bending movement, or low mobility) is an important risk factor for low back pain. "Previous studies had given conflicting results on this issue, probably because they used inaccurate 'clinical' measures of lumbar mobility," says Adams. "We used an accurate electromagnetic tracking device to measure lumbar mobility."

Adams says a second major finding is that physical risk factors have more influence in those people who are starting out in a physically demanding new job. "This had not been studied before," Adams tells WebMD. He believes more research needs to be done to determine if people are more likely to develop back pain when starting a new job based on their physical characteristics, including trunk length, back muscle strength, and mobility. Adams is a senior research fellow at Bristol University.

Adams says that behavior such as poor lifting technique naturally can cause lower back pain. He also noted that one other behavior can: smoking. Researchers whose findings appeared in the April 1999 issue of Occupational Medicine came to the same conclusion.

D. Ehrmann Feldman, PhD, a post-doctoral fellow at the University of Montreal who studied 500 students between grades 7 and 9, agrees. "The most important finding of the study was that smoking appears to be a risk factor for the development of low back pain in adolescents," Feldman tells WebMD. "We found that teens who smoked were approximately 2.5 times as likely to develop low back pain as nonsmokers. We also found a dose-response association; those students who smoked more were more likely to develop low back pain."

Feldman says one intriguing aspect of this study of smoking and back pain is that these students could not have had very long smoking histories since they were so young. "It may be that relatively short smoking histories are detrimental to growing tissue," he tells WebMD. While there have been other studies showing a connection between smoking and lower back pain, the Canadian research is the first one to show a relationship between smoking and low back pain in young people.

How does smoking hurt people's backs? Smoking reduces blood circulation all over the body, even in the tissues of the lower spine. Less circulation means more risk for back pain and less ability to heal injuries.

Feldman believes this information should be publicized among young people. While the young are well aware of the risks of cancer and heart disease from smoking, publicizing those risks haven't had much of an effect on deterring young people from smoking. "Although anti-smoking campaigns have not been all that successful with teenagers, it is hoped that as more adverse reactions to smoking are discovered, the appeal of smoking will be diminished for young people," Feldman tells WebMD. "Now maybe we can add healthier backs to the benefits of quitting or not starting."

Feldman believes further study on biological effects of smoking in growing adolescents on musculoskeletal tissue, specifically, the spine, may be warranted.

Vital Information:

A new study shows that physical factors, such as a long, stiff, and flat lumbar spine, are better predictors of low back pain than psycho-social factors or engaging in strenuous activity.

  • Other risk factors for developing low-back pain are improperly lifting objects and smoking.
  • Researchers say that smoking causes low-back pain possibly because it reduces blood circulation and may even damage growing tissue in adolescents.