Some of our Elf friends were discussing a recent talk from a shoulder surgeon colleague who commented on the link between smoking and poor outcomes after shoulder surgery. We knew that smoking was associated with increased risk of fracture, delayed and non-union of fractures, and reduced bone mineral density because of the effects of nicotine on blood flow, but not shoulder pain. This lead us to dig a bit deeper and we found this very interesting review looking at the effect of smoking on the rotator cuff (RTC) muscle group.

Here’s what they did

The authors searched PubMed, CINAHL, SPORTDiscus, and The Cochrane Library using PRISMA guidelines for English language clinical articles studying smoking and shoulder function. Level I-IV studies analysing anatomy, histology, pathology, biomechanics, or imaging characteristics were also included. For data analysis any continuous variable data were reported as means and standard deviations from the means; categorical variable data were reported as frequencies with percentages. Associations were reported as odds ratios (ORs) with corresponding 95% confidence intervals (CIs), p< 0.05 was considered significant.

Here’s what they found

Thirteen studies were identified comprising 16,172 patients, of whom 6,081 were smokers.

Four clinical studies found smoking was associated with poor shoulder function and pain scores:

• Smoking correlated with Simple Shoulder Test scores (p=0.003), greater when combined with female sex and work-related injury (p < .001). Smokers had worse mean scores on the Subjective Shoulder Rating System assessment (p = 0.005), Shoulder Rating Questionnaire (p=0.0008), and Oxford Shoulder Questionnaire (p=0.0042). However, there was no correlation with ASES scores (p=0.184).
• Currently smoking men (>20 pack years) were at highest risk of unilateral shoulder pain (OR, 1.9; 95% CI, 1.3 to 2.9)
• Currently smoking women (10-20 pack years) were at highest risk of bilateral shoulder pain (OR, 1.8; 95% CI, 1.0 to 3.1)
•  Smokers reported lower active range of motion (p=0.024)., with no significant difference between smokers of <1 pack per day and smokers of 1 pack per day.
• Smokers had higher preoperative pain scores (p<0.0001)

Smoking was not found to be associated with chronic RTC tendinitis.

Studies exploring the correlation between smoking and RTC disease (n=4) reported mixed results.

• A time- and dose-dependent relation was found between smoking and ultrasound diagnosed RTC tears, increasing when smoking occurred within 10 years of presentation (OR, 4.24; CI, 1.75 to10.25; p= 0.0006). This was significant in patients with a history of smoking 1 to 2 packs per day (OR, 1.66; p= 0.009) and greater for 2 packs per day (OR, 3.35; p=0.0007)
• Current smokers were found to be at greater risk of impingement syndrome (diagnosed using local anaesthetic injection) than non-smokers (OR, 6.8; 95% CI, 1.2 to 39).
• However another study using ultrasound imaging reported no statistically significant association between smoking and increasing RTC tear prevalence (p=0.52), and a case control study concluded that current smoking status was not associated with RTC disease (OR, 1.03: 95%CI, 1.1-1.39).

Four further studies showed  links between  smoking and increasing degree of  RTC pathology, with larger tears, higher degeneration, and increased number of tears at a younger age. One study on rats found nicotine increased stiffness in the supraspinatus tendon.

The authors concluded

Smoking is associated with RTC tears, shoulder dysfunction, and shoulder symptoms. Smoking may also accelerate RTC degeneration and increase the prevalence of larger RTC tears.

The Musculoskeletal Elf’s view

The authors of this systematic review warned that due to limitations it is challenging to draw generalizable conclusions from the studies. Nevertheless this is a fascinating review and raises awareness of an association between smoking and cuff pathology.

What do you think?

Have you considered the link between smoking and rotator cuff pathology?

How would you approach this subject with shoulder patients?

Send us your views on this blog and become part of the ever expanding Musculoskeletal Elf community. Post your comment below, or get in touch via social media (Facebook, Twitter, LinkedIn, Google+).

Links

• PRISMA statement
• EQUATOR Network

Bishop, J.Y, Santiago-Torres, J.E, Rimmke, N, Flanigan D.C, 2015, ‘Smoking Predisposes to Rotator Cuff Pathology and Shoulder Dysfunction: A Systematic Review’, Arthroscopy, article in press