All analyses were adjusted for age and body mass index (BMI). Covariates appearing in the model are evaluated at the following values; age = 69.1, BMI = 24.5. A p value less than 0.05 was considered to be significant. Data indicates mean (SD, 95%CI) and p (95%CI for differences). K/L: Kellegren and Laurence grade. *: vs. K/L 1, ¶: vs. K/L 2, †: vs. K/L 3.