How Does Smoking Affect the Severity of Chronic Pain?

by | Dec 4, 2020 | Low Back Pain, Physical Therapy / Medicine and Rehabilitation | 0 comments

Person holding their neck because it is in pain

Chronic pain is a common condition experienced by an estimated 20.4% of US adults, according to the CDC. (1) Chronic pain can come in the form of back pain, arthritis, muscle pain, and more and is caused by many underlying diseases and factors. (1) Smoking is known to worsen chronic pain, and studies have shown a higher prevalence of back pain among current smokers versus non-smokers and former smokers. (2,3) There are many studies on the how smoking can promote muscular pain by influencing pain sensitivity, vasoconstriction, and pro-inflammatory effects. (4,7,10)

Smoking Reduces Pain Threshold 

Smoking is often used as an analgesic to reduce pain and negative emotions. However, studies have proposed that nicotine causes a feedback loop because consistent use of nicotine causes dependence and an increasingly higher tolerance for the substance. Increased tolerance in turn leads to reduced pain inhibition and greater pain perception. (4) Smokers are found to have severe chronic pain more often than nonsmokers due to this feedback loop. One study had 12,368 patients complete a questionnaire, and the results showed the smoking patients had significantly worse pain intensities (P <0.001). (5) While cigarettes initially reduce pain, long-term use of smoking can negatively impact patients, causing a decreased pain threshold that increases the likelihood of chronic pain. 

Smoking Causes Muscle Fatigue 

It is known that smoking causes vasoconstriction which reduces blood flow. (3) Constricted blood flow will also reduce the availability of nutrient-filled blood. The lack of oxygen available in the blood can directly impact the skeletal muscles and cause muscle fatigue. (3) In a recent study, 40 smokers and 45 non-smokers of the same age and physical activity level were tested for skeletal muscle function, which included maximal strength, contractile properties, and fatigability. The contractile speed and maximal strength were the same among smokers and non-smokers. However, muscle fatigue was greater in smokers (P=0.014), though this result did not correlate with the number of cigarette packs smoked. The increased skeletal muscle fatigue was speculated to be caused by impaired oxygen delivery in the blood. (6) Indeed, the study indicates that smoking causes muscle fatigue which can be a critical factor in developing chronic musculoskeletal pain. (6,7)

Smoking Increases Inflammatory Responses 

Another mechanism by which smoking contributes to back pain is through promoting inflammation. (2) Smoking has been shown to increase levels of inflammatory markers such as C-reactive proteins and leukocytes. (8) According to the Mayo Clinic, smokers have an increased risk for more severe rheumatoid arthritis. (9) The inflammatory responses occur through reactive oxidative substances that damage the airway cells’ epithelial lining. This damage starts the signaling cascade to activate inflammatory genes that promote inflammation and immune cell recruitment. Constant inflammation can impair the immune system and healing abilities. (10) A study that assessed the relationship between cigarette smoking to knee pain and cartilage loss examined 159 men with symptomatic knee osteoarthritis. Out of 159 men, 19 were current smokers and were on average younger than the non-smokers. Despite being younger than the other participants, the smoking group had a higher risk of cartilage loss at the medial tibiofemoral joint than non-smokers. (11) The study concluded that smoking increased the risk of cartilage loss and severe knee pain, possibly due to the release of reactive oxidative substances from smoking. The study also showed increased severity of osteoarthritis in the smoking population. (11)

The research shows smoking can act across many mechanisms throughout the body to magnify chronic pain. Long-term smoking creates tolerance and dependence on nicotine resulting in a reduced pain threshold. The vasoconstrictive effects of smoking result in oxygen-deficient blood reaching the skeletal muscles causing decreased energy and fatigue. Smoking also promotes inflammation by damaging the airway epithelial cells, which activates inflammation. These effects on the body increase the severity of chronic pain in smokers. 

Citations:

  1. Prevalence of Chronic Pain and High-Impact Chronic Pain Among Adults – United States, 2016. (2019, September 16). Retrieved December 02, 2020, from https://www.cdc.gov/mmwr/volumes/67/wr/mm6736a2.htm
  2. Green, B. N., Johnson, C. D., Snodgrass, J., Smith, M., & Dunn, A. S. (2016). Association Between Smoking and Back Pain in a Cross-Section of Adult Americans. Cureus, 8(9), e806. https://doi.org/10.7759/cureus.806
  3. Team, C. (2020, August 21). Why Smoking Will Worsen Your Chronic Pain. Retrieved December 02, 2020, from https://health.clevelandclinic.org/why-smoking-will-worsen-your-chronic-pain/
  4. Chapman, S. L., & Wu, L. T. (2015). Associations between cigarette smoking and pain among veterans. Epidemiologic reviews, 37(1), 86–102. https://doi.org/10.1093/epirev/mxu008
  5. Khan, J. S., Hah, J. M., & Mackey, S. C. (2019). Effects of smoking on patients with chronic pain: a propensity-weighted analysis on the Collaborative Health Outcomes Information Registry. Pain, 160(10), 2374–2379. https://doi.org/10.1097/j.pain.0000000000001631
  6. Wüst, R. C., Morse, C. I., de Haan, A., Rittweger, J., Jones, D. A., & Degens, H. (2008). Skeletal muscle properties and fatigue resistance in relation to smoking history. European journal of applied physiology, 104(1), 103–110. https://doi.org/10.1007/s00421-008-0792-9
  7. Yokoyama, T., Lisi, T. L., Moore, S. A., & Sluka, K. A. (2007). Muscle fatigue increases the probability of developing hyperalgesia in mice. The journal of pain : official journal of the American Pain Society, 8(9), 692–699. https://doi.org/10.1016/j.jpain.2007.05.008
  1. Smoking and Inflammation. (2005). PLoS Medicine, 2(6), e198. https://doi.org/10.1371/journal.pmed.0020198
  2. April Chang-Miller, M. (2020, March 26). Does smoking boost rheumatoid arthritis risk? Retrieved December 02, 2020, from https://www.mayoclinic.org/diseases-conditions/nicotine-dependence/expert-answers/rheumatoid-arthritis-smoking/faq-20119778
  3. Lee, J., Taneja, V., & Vassallo, R. (2012). Cigarette smoking and inflammation: cellular and molecular mechanisms. Journal of dental research, 91(2), 142–149. https://doi.org/10.1177/0022034511421200
  4. Amin, S., Niu, J., Guermazi, A., Grigoryan, M., Hunter, D. J., Clancy, M., LaValley, M. P., Genant, H. K., & Felson, D. T. (2007). Cigarette smoking and the risk for cartilage loss and knee pain in men with knee osteoarthritis. Annals of the rheumatic diseases, 66(1), 18–22. https://doi.org/10.1136/ard.2006.056697

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