Objective: The purpose of this study was to analyze the longitudinal association between physical activity levels and early degenerative cartilage changes in the knee, measured using T2 relaxation times over a period of 4 years in individuals without clinical or radiographic evidence of OA. Design: Cartilage T2 was measured at baseline and after 2 and 4 years in 205 subjects aged 45-60 years from the Osteoarthritis Initiative (OAI) incidence and normal cohorts with no knee pain (Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score of zero), and a Kellgren Lawrence (KL) score of <2 at baseline. Physical activity was scored using the Physical Activity Scale for the Elderly (PASE) questionnaire, which was obtained yearly over 4 years. The relationship between physical activity and T2 was studied using a mixed model linear regression, including random effects, and adjusted for age, sex, and body mass index (BMI). Results: T2 values for all PASE tertiles progressed over the 4-year period. T2 progression was increased in the highest tertile of physical activity compared to the mid-tertile at the medial tibia (MT) (P=0.041), patella (Pat) (P=0.019), and average T2 of all knee compartments combined (P=0.033). Subjects with the lowest 15% PASE scores showed significantly higher T2 progression compared to the mid-level physical activity group at the lateral femur (LF) (P=0.025), lateral tibia (LT) (P=0.043), medial femur (MF) (P=0.044), tibiofemoral compartment (P=0.017), patellofemoral compartment (P=0.016), lateral compartments (P=0.003), and average of all compartments (P=0.043). Conclusion: High and very low PASE scores were associated with greater progression of cartilage T2 measurements in asymptomatic, middle-aged individuals, suggesting accelerated cartilage matrix biochemical degeneration over time. © 2013 Osteoarthritis Research Society International.
Lin, W., Alizai, H., Joseph, G. B., Srikhum, W., Nevitt, M. C., Lynch, J. A., … Link, T. M. (2013). Physical activity in relation to knee cartilage T2 progression measured with 3tmri over a period of 4 years: Data from the osteoarthritis initiative. Osteoarthritis and Cartilage, 21(10), 1558–1566. https://doi.org/10.1016/j.joca.2013.06.022