Epidemiological aspects of osteoarthritis.

An epidemiological approach can shed some light on several aspects of osteoarthritis (OA). OA is an ubiquitous condition, with an age-linked prevalence, rising slowly until the age of 50 and rapidly thereafter, especially in women. Its etiology is clearly multifactorial, the main factors being ageing, mechanical stress hereditary and/or constitutional factors, and inflammation. Structural and physical features of cartilage alter with age. These alterations are underlaid by biochemical changes. Mechanical stress is sometimes acute but most often long-standing. Familial or constitutional factors, or the possible triggering role of inflammation, are particularly well documented in certain subsets of OA. Finally, the possibility of an underlying metabolic disturbance remains a stimulating, though yet unproven, prospect.