ROCHESTER, Minn. -- New findings from a study led by a Mayo Clinic rheumatologist indicate that men with knee osteoarthritis who smoke experience greater cartilage loss and more severe pain than men who do not smoke. Results will be published online this week in the Annals of the Rheumatic Diseases.

Knee osteoarthritis is one of the leading causes of disability in elders.

This is a novel finding, says Shreyasee Amin, M.D., Mayo Clinic rheumatologist and lead study researcher. Previous studies showed no association between cigarette smoking and knee osteoarthritis or even a protective effect of smoking.

The finding that cigarette smoking plays a role in the worsening of knee osteoarthritis is important, says Dr. Amin, as it is a potentially modifiable risk factor.

To conduct this study, the researchers examined 159 men with symptomatic knee osteoarthritis who participated in a prospective study on the natural history of the condition, the Boston Osteoarthritis of the Knee Study. The current study focused on men, as there were too few women in the original group studied who smoked (4 percent). The researchers took MRIs (magnetic resonance images) of the more symptomatic knee of each patient at the study beginning, and also 15 and 30 months later. Cartilage loss over follow-up, based on knee MRIs, was determined at the tibiofemoral joint (the connection between the thighbone and shinbone) and the patellofemoral joint (the junction of the knee cap and the thigh bone) in the knees, and a scoring tool was used to assess knee pain severity. Nineteen, or 12 percent, of the men were current smokers at the studys start. These men also were leaner and younger than other study participants, so the researchers adjusted for these factors. The investigators found current smokers had a 2.3 fold increased risk of cartilage loss at the medial tibiofemoral joint and a 2.5 fold increased risk of cartilage loss at the patellofe
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Contact: Dana Sparks
newsbureau@mayo.edu
507-284-5005
Mayo Clinic
7-Dec-2006