Less collagen production in smokers

An association between smoking and impaired wound healing has been reported in retrospective studies. The smoking status of a surgical patient may be confounded by social and medical parameters. We have evaluated the effect of smoking in a test wound in volunteers, with special reference to a reliable scientific match between smokers and nonsmokers.

In a prospective open study with blinded assessment, 19 smoking (20 cigarettes/day) and 18 nonsmoking healthy volunteers were matched with respect to baseline characteristics. The deposition of total protein and mature collagen (expressed as hydroxyproline) was assessed in an expanded polytetrafluoroethylene wound healing model implanted subcutaneously for 10 days.

The nonsmokers had a 1.8 times higher median amount of hydroxyproline than the smokers (p < 0.01). The deposition of hydroxyproline was negatively correlated with the consumption of tobacco both before (r = -0.44; p < 0.01) and during the study (r = -0.48; p < 0.005). The impairment was specific for the production of collagenous proteins and not other proteins.

The synthesis of subcutaneous collagen in smokers is specifically impeded, indicating an impaired wound-healing process. Because mature collagen is the main determinator of strength of an operative wound, the results support the view that patients should be advised to stop smoking before an operation.