NEW YORK (Reuters Health) – Individuals with a family history of osteoarthritis (OA) and who smoke have a greater rate of knee cartilage loss and knee defects than similar individuals with a family history of OA but who do not smoke.

Dr. Changhai Ding of Menzies Research Institute in Hobart and colleagues conducted a multicenter study of the offspring of patients with severe primary osteoarthritis who underwent knee replacement surgery at Hobart, Australia-area hospitals and randomly selected controls without a family history of OA.

They identified 325 subjects, 163 with a family history of OA, with a mean age of 45 years. Patients were assessed at baseline and again 2.3 years later. Investigators assessed knee cartilage volume and defect scores on a scale of 0-4 using T-weighted fat-saturated magnetic resonance imaging (MRI). Smoking status and number of cigarettes smoked per day were recorded.

Current smoking and smoking history of 20 pack years or more was associated with a significant drop in medial and lateral cartilage volume. There was an annual loss of 2.2% medially and 1.45% laterally in current smokers when compared with never smokers and former smokers.

"This study is the first to demonstrate harmful effects of smoking on both cartilage volume loss and cartilage defect development mainly in persons with a family history of severe knee OA," Dr. Ding’s group writes in the May issue of Arthritis and Rheumatism.

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