Smokers with knee arthritis suffer quicker joint deterioration than non-smokers with the condition. Cartilage is the elastic tissue that cushions the ends of the bones; in osteoarthritis - the common 'wear-and-tear' form of arthritis - this cartilage gradually breaks down, leading to inflammation, pain and deformity in the bones. Some past studies, though not all, have suggested that smokers might be at greater risk of osteoarthritis. The following study suggests that when smokers do develop the condition, it may be more severe. Researchers from the Mayo Clinic College of Medicine in Rochester, Minnesota, USA, studied 159 men with knee osteoarthritis in the study and followed them for 2.5 years. The researchers used MRI scans to measure cartilage loss in the knee at the beginning, midpoint and end of the study. The men also rated their knee pain at each follow-up visit. In general, it was found that 12 percent of men who were smoking at the study's outset showed greater cartilage loss over time and reported more pain than their non-smoking counterparts. This was despite the fact that the smokers tended to be younger and weigh less, which might be expected to delay progression of their arthritis. There are a number of reasons smoking could exacerbate arthritis. For one, smoking can deprive tissue of oxygen, which might hinder normal cartilage repair. In addition, since cartilage itself has no pain fibers, it's possible that smokers' greater pain comes from damage to other structures in the arthritic joint. The above findings are provocative and should spur further research.
Annals of the Rheumatic Diseases,
December 2006