The Osteoarthritis Prevention Study

Structural knee Osteoarthritis (OA) MRI change Scores

Compare the effects of a 48-month intervention of dietary weight loss, exercise, and weight-loss maintenance to an attention control group in preventing the development of structural (MRI) knee OA. Assessed using the MRI Osteoarthritis Knee Score (MOAKS). The MOAKS evaluates degenerative changes in the knee, including the location and severity of osteophyte formation, bone marrow lesions, and cartilage loss. The MOAKS classification system of osteophytes has grades ranging from 0 (none) to 3 (large).

Knee Pain Scores

Compare the effects of a 48-month intervention of dietary weight loss, exercise and weight-loss maintenance to an attention control group on the Knee Injury and Osteoarthritis Outcome Score (KOOS pain). Standardized answer options are given (5 Likert boxes) and each question is assigned a score from 0 to 4. A normalized score is calculated for the pain subscale. We will transform the score to a 0-100 scale, with 100 representing the most pain and 0 representing no pain.

Mobility Scores

Compare the effects of a 48-month intervention of dietary weight loss, exercise and weight-loss maintenance to an attention control group on 6-minute walk distance. Assessment of 6 minute walk distance (measured in meters). Greater distance indicates better mobility.

Health-Related Quality of Life Scores

Compare the effects of a 48-month intervention of dietary weight loss, exercise and weight-loss maintenance to an attention control group on health-related quality of life (SF-36). Questions from the SF-36 yield 2 broad summary scores: physical health and mental health. Scores for each domain range from 0 to 100, with a higher score defining a more favorable health state.

Knee Joint Loading Number

Compare the effects of a 48-month intervention of dietary weight loss, exercise, and weight-loss maintenance to an attention control group on knee joint compressive loads (Newtons). Higher numbers indicate greater loads.

Inflammation Value

Compare the effects of a 48-month intervention of dietary weight loss, exercise, and weight-loss maintenance to an attention control group on plasma Interleukin-6 (IL-6). Higher values indicate more inflammation.

Self-Efficacy Scores - exercise

Compare the effects of a 48-month intervention of dietary weight loss, exercise, and weight-loss maintenance to an attention control group on exercise self-efficacy. Exercise self efficacy will be measured using the walking efficacy for duration scale measures one's ability to walk/jog at a moderately fast pace for various durations. Range 0-100. A higher score indicates a higher self-efficacy. indicate better self-efficacy.

Self-Efficacy Scores - weight loss

Compare the effects of a 48-month intervention of dietary weight loss, exercise, and weight-loss maintenance to an attention control group on weight loss self-efficacy. Weight-loss self efficacy will be measured by the weight efficacy lifestyle questionnaire. A 20-item measure developed to assess self-efficacy for weight management. Participants are asked to rate their confidence to resist the desire to eat using a 10-point scale ranging from 0 not confident to 9 very confident. Total scores range from 0-180. Higher scores indicate better self-efficacy.