THE INCIDENCE AND NATURAL-HISTORY OF KNEE OSTEOARTHRITIS IN THE ELDERLY - THE FRAMINGHAM OSTEOARTHRITIS STUDY

Objective, To determine the incidence of radiographic knee osteoarthri tis (OA) and symptomatic OA (symptoms plus radiographic GA), as well a s the rate of progression of preexisting radiographic OA in a populati on-based sample of elderly persons, Methods, Framingham Osteoarthritis Study subjects who had knee radiographs and had answered questions ab out knee symptoms in 1983-1985 were reexamined in 1992-1993 (mean 8,1- year interval) using the same protocol, Subjects were defined as havin g new (incident) radiographic OA if they developed grade greater than or equal to 2 OA (at least definite osteophytes or definite joint spac e narrowing), New symptomatic OA was present if subjects developed a c ombination of knee symptoms and grade greater than or equal to 2 OA, P rogressive OA was diagnosed when radiographs showing grade 2 disease a t baseline showed grade greater than or equal to 3 disease on followup . Results, Of 1,438 participants in the original study, 387 (26.9%) di ed prior to followup, Of the 1,051 surviving subjects, 869 (82.7%) par ticipated in the followup study (mean +/- SD age 70.8 +/- 5.0 at basel ine), Rates of incident disease were 1.7 times higher in women than in men (95% confidence interval [CI] 1.0-2.7), and progressive disease o ccurred slightly more often in women (relative risk = 1.4; 95% CI 0.8- 2.5) but rates did not vary by age in this sample, Among women, approx imately 2% per year developed incident radiographic disease, 1% per ye ar developed symptomatic knee OA, and about 4% per year experienced pr ogressive. knee OA, Conclusion, In elderly persons, the new onset of k nee OA is frequent and is more common in women than men, However, amon g the elderly, age may not affect new disease occurrence or progressio n.