It is well known that COPD patients have weak muscles which contributes to their respiratory problems. It has been thought that the weakness was likely secondary to the chronic lung disease and it's resulting sedentary lifestyle. In a recent article in Chest Montes de Oca et al. show that the effect of cigarettes may,in fact, be direct. They biopsied the vastus lateralis muscle of 14 long time smokers that did not have COPD by pulmonary function testing and were able to demonstrate differences in comparison with a control group of non-smokers with similar sedentary lifestyles. The muscles of the smokers had atrophy of the type1 fibres and a shift to glycolytic rather than oxidative metabolism. There was no sign of inflammation,however.
I guess it's no big surprise that cigarettes are toxic to muscle, as they are to a myriad of other tissues, but it does raise the question as to whether cigarettes may have a greater impact on musculo-skeletal physiology than was suspected to date.