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Monday, December 1, 2014

Smoking Linked to Chronic Pain

There was a time when physicians actually recommended smoking. The American medical community now agrees that smoking is not a good idea, and smoking rates are dropping. A significant majority of physicians surveyed do see merit in marijuana, but the news is not clear as to whether they approve of smoking it as opposed to consumption of the plant's derivatives. It would be interesting to know if those doctors see the benefits outweighing the dangers if the substance was smoked.

Turns out smoking may be a bigger issue than just the various diseases linked to it by the Center for Disease Control (CDC), including cancer, asthma, COPD, diabetes, heart disease, and stroke (to name a few). It may also be a comorbidity or at least an aggravating factor for pain. A recent study from Northwestern University concludes that "smoking is a pain in the back." 

There are a significant number of workers' compensation cases that involve pain from a work injury and a variety of modalities employed to combat it. Pain has received attention in articles like Chronic Pain Workers' Comp Claims Increasing for Employers and Opiod Epidemic Plagues Workers' Comp.

The Northwestern study is "a longitudinal observational study of 160 adults with new cases of back pain." A longitudinal study gathers data "for the same subjects repeatedly over a long period of time;" they can "extend over years or even decades," according to Whatis. The point is that various people are studied as they live their lives, as opposed to studying various sets or groups of people at selected times. A longitudinal study is similar to a movie with successive scenes, as opposed to taking snapshots ("selfies" for those in the next generation) of different subjects at specific times. 

This Northwestern study in particular, published in the journal Human Brain Mapping, studied "thirty-five healthy control participants and 32 participants with chronic back pain" over the course of a year. It was a study that involved an examination of the human brain using objective diagnostic testing. 

A magnetic resonance image (MRI) was administered to each study participant on five occasions during the study. The MRI, according to Medical News Today "uses a magnetic field and radio waves to create detailed images of the body." A technology that is well familiar to the workers' compensation industry, the MRI can help physicians see how a patient's internal physiology is functioning. Unlike an X-ray which creates images of bones, the MRI creates images of soft tissue.

The researchers used the MRI scans to focus on two areas of the brain, the "nucleus accumbens and medial prefrontal cortex." They concluded that these "two regions of the brain 'talk' to one another" and that the "strength of that connection (between the two) helps determine who will become a chronic pain patient." In other words, the interaction of these brain systems plays a role in how we as individuals perceive pain in our bodies.

The research and MRI scans supported that the connection between these two particular brain processes "was very strong and active in the brains of smokers," and that the connection was diminished in "smokers who - of their own will - quit smoking during the study."

Essentially, "when they stopped smoking, their vulnerability to chronic pain also decreased." The perception of pain, it seems, is enhanced when the communication between these two brain areas is enhanced. Smoking appears to play a role in increasing communication and thus enhances the perceptions of pain. 

Another interesting component of the test was medication. Patients who took anti-inflammatory drugs did report they were of help in the management of pain. However, the medications "didn't change the activity of the brain circuitry." In other words, while the medication had a therapeutic effect on the perception of pain itself, the medication did not decrease the communication or connection between these two portions of the brain. 

Certainly not an end to the analysis of pain, but interesting. If someone needed yet another reason to discontinue smoking, perhaps this is it. Regardless of the reason for the onset of pain, smoking may increase the perception of it. And, there is evidence that smoking cessation may be of benefit in decreasing the perception of pain after onset.