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Smoking linked to shoulder injuries

 •  • by Paul Ingraham
Weekly nuggets of pain science news and insight, usually 100-300 words, with the occasional longer post. The blog is the “director’s commentary” on the core content of a library of major articles and books about common painful problems and popular treatments. See the blog archives or updates for the whole site.

Smoking is strongly linked to more shoulder pain and injuries, which is quite odd. This seems to be excellent evidence of two principles:

  1. There doesn’t seem to be ANYTHING that smoking will not make worse.
  2. Musculoskeletal pain/injury that seems “mechanical” is often more about subtle biological vulnerability.

This review by Bishop et al considered thirteen studies of shoulder trouble in about 6000 smokers out of 16,000 patients. The studies showed clear links between smoking and rotator cuff tears: more tears and worse tears, with more degenerative signs later on. That is, the “cuff” of muscles around the shoulder joint is apparently more fragile in smokers. They also found a link with unexplained chronic shoulder pain and dysfunction. One experimental study showed that nicotine made rat shoulder tendons stiffer.

Smoking is bad for your shoulders! And here’s a weird theory …

Could the mechanism for this be low vitamin C, which happens to smokers? Vitamin C is critical for collagen (connective tissue) synthesis, which is the why the disease of scurvy causes wrecks people. On the one hand, this seems implausible because minor connective tissue disorders from vitamin C deficiency would pretty much just be scurvy by definition — mild scurvy, but scurvy! And I don’t think smokers get scurvy. Easy dismissal, right? Not so fast! On the other hand, subclinical scurvy could actually be a thing, and it is not a new idea. Mild symptoms are easily missed, and it wouldn’t shock me if one of the only signs of trouble was an increased risk something (like connective tissue trauma). I can imagine that connection being missed indefinitely. I doubt anyone has ever looked for it. See this article (very old, but very readable), and this one, and this study.

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