Every pound of weight loss results in a roughly fourfold reduction in the load exerted on the knee during daily activities, which can impact pain. Although the link between obesity and osteoarthritis was once considered purely biomechanical, it has become clearer that other factors, such as decreased muscle mass and excess inflammation from obesity, may play a role in the link between the conditions.7
The WE-CAN randomized trial investigated whether interventions adapted from the IDEA trial could be implemented in non-academic, community settings.
Previous work has shown that a loss of 5% body weight provides some pain relief in obese people with osteoarthritis; a reduction of 10% doubles that pain relief. In addition to aiding weight loss, exercise provides other benefits in osteoarthritis, such as strengthened muscles, improved physical function and reduced pain.7
The current ACR guideline strongly recommends exercise for patients with knee osteoarthritis as well as weight loss for those who are overweight or obese.8 However, many physicians who treat these patients are not sure how to best help them implement these lifestyle changes.
Some academic centers have successfully implemented diet and exercise interventions in such patients. Dr. Messier noted that in the IDEA efficacy trial, in which he was also an investigator, the participants who received both a dietary and exercise intervention reduced their pain by 51% over 18 months as assessed by the Western Ontario and McMaster Universities Arthritis Index (WOMAC). That same trial found that exercise plus diet interventions were more successful at reducing pain, inflammation and knee joint loads than either intervention alone.9
WE-CAN Study Results
The WE-CAN randomized trial investigated whether interventions adapted from the IDEA trial could be implemented in non-academic, community settings.6 The trial took place at several rural and urban counties in North Carolina in such facilities as a local hospital community fitness center and a church recreation facility; study physicians trained commonly available community staff to diagnose knee osteoarthritis.
All participants were age 50 or older with knee osteoarthritis and a body mass index of at least 27 kg/m2. The researchers randomized the participants into a diet plus exercise group of a 414- or a 409-member attention control group. Ultimately, 80% of the participants completed the study.
The exercise component consisted of two 15-minute walking periods, separated by a 20-minute weight training session, three days a week. For the diet component, the participants ate and logged a reduced calorie diet of their choice, which could include low calorie meal replacement shakes. Members in the attention control group received nutrition and health education, including five one-hour meetings interspersed with phone meetings or health informational packets.
