Knee arthritis commonplace amongst seniors

Study results have shown that nearly half of Americans will have osteoarthritis, a leading cause of disability in the US, in at least one knee by the time they reach 85.

The study of 3,068 people revealed that the lifetime risk of having symptomatic knee osteoarthritis was 44.7%. Sex, race, and level of education, did not appear to affect the risk of developing arthritis. Two factors that were found to have a significant impact on risk were previous knee injuries and being overweight or obese.

The risk of developing arthritis in one knee by the age of 85 in those with a history of knee injury was 56.8 %, compared with 42.3 % in participants without previous knee injury.  Obesity was found to double the risk of developing knee arthritis. The risk in obese participants was 60.5%, compared to 46.9% in overweight participants, and 30.2% in participants of normal weight.  

Joanne Jordan, MD, a senior author of the study and principal investigator of the Johnston County Osteoarthritis Project, said of the findings: "Simply put, people who keep their weight within the normal range are much less likely to develop symptomatic knee osteoarthritis as they get older and thus much less likely to face the need for major surgical procedures, such as knee replacement surgery. These results show how important weight management is for people throughout their lives."

Murphy L, Schwartz TA, Helmick CG, Renner JB, Tudor G, Koch G, Dragomir A, Kalsbeek WD, Luta G, Jordan JM. Lifetime risk of symptomatic knee osteoarthritis. Arthritis Rheum. 2008;59:1207-1213.

Murphy, L. Arthritis & Rheumatism, September 2008; vol 59: pp 1207-1213.
Nearly half of U.S. adults will develop painful knee osteoarthritis by age 85: study. News release. 2nd September 2008. University of North Carolina at Chapel Hill School of Medicine website.