Here is another reason to stop smoking: Men who have osteoarthritis of the knee and they smoke have greater cartilage loss and more severe pain than men who do not smoke, according to results of a recent study.

The study, published online in the Annals of the Rheumatic Diseases, examined the symptomatic knees of 159 men. Monitored for up to 30 months, the men’s knees were scanned using a MRI and their pain level was scored. Nineteen of the men were active smokers at the beginning of the study, and they smoked an average of 20 cigarettes a day for about 40 years.

The study results showed that the smokers were more than twice as likely to have significant cartilage loss than the non-smokers. Reasons that may explain the link between smoking and cartilage loss include:

• Smoking may disorder the cells and deter cell production in cartilage.
• Smoking may raise levels of toxins in the blood, contributing to cartilage loss.
• Smoking may increase carbon monoxide levels in the blood, affecting blood oxygenation, which could impede cartilage repair.

Additionally, the smokers had higher pain scores than the non-smokers. Increased pain may not be caused by cartilage loss, since researchers found that cartilage does not have pain fibers. However, smoking may impact other structures in the knee or may have an effect on pain perception.