BONE-MINERAL DENSITY AND KNEE OSTEOARTHRITIS IN ELDERLY MEN AND WOMEN- THE FRAMINGHAM-STUDY

Objective. To examine the possible inverse relationship between osteop orosis and osteoarthritis (OA) by evaluating the association between b one mineral density (BMD) and knee OA in the Framingham Study cohort. Methods. Of the 1,154 Framingham Study cohort subjects in whom BMD mea surements were obtained at biennial examination 20, 932 (81%) had had knee OA assessed during the Framingham Knee OA Study 4 years earlier. BMD of the proximal femur and radius was measured by densitometry. Kne e OA was assessed from a weight-bearing anteroposterior radiograph and graded on a scale of 0 (no OA) to 4 (severe OA). Osteophytes and join t space narrowing were also evaluated separately. Linear regression wa s used to test the association of BMD with knee OA, with osteophytes, and with joint space narrowing, after adjustment for age, body mass in dex, and mean number of cigarettes smoked per day. Results. The subjec ts included 572 women and 360 men with an age range of 63-91 years (me an 71 years). Of these, 351 had no OA, 269 had grade 1 OA, 170 had gra de 2 OA, 93 had grade 3 OA, and 49 had grade 4 OA. Mean femoral BMD at the 3 proximal femur sites was 5-9% higher in men and women with eith er grade 1, grade 2, or grade 3 knee OA, compared with those with no k nee OA (P < 0.0001). Mean femoral BMD in those with grade 4 OA was not higher than in those with no OA. Radius BMD was not associated with k nee OA in subjects of either sex. Women with osteophytes had higher BM D compared with women with no osteophytes. Mean BMD did not differ acr oss levels of joint space narrowing. Conclusion. We conclude that, amo ng women, femoral BMD is higher in those with osteophytosis of the kne e, and BMD is not necessarily associated with joint space narrowing.