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Knee osteoarthritis responds best to program of diet plus exercise, research shows

Sept. 25, 2013

A combination of intensive diet and exercise was more effective in treating knee osteoarthritis in overweight and obese adults than either diet or exercise alone. A research study comparing the three programs found that the combination program resulted in the most improvements in both pain and function.

The study, which was led by researchers at Wake Forest University in North Carolina, included 454 knee osteoarthritis patients. All of the patients were over 55 years old and were overweight or obese, which aggravates osteoarthritis. They were randomly assigned to one of three programs:

  • An intensive diet with the goal of losing at least 10 per cent of the patient’s body weight. On the program, patients used meal-replacement shakes for up to two meals a day, and weekly menu plans for remaining meals. Fewer meal-replacement shakes were used as the program progressed.
  • An exercise program consisting of one hour of activity, three times per week. Each hour-long session consisted of 15 minutes of aerobic walking, 20 minutes of strength training, another 15 minutes of aerobic walking, and 10 minutes of cooldown.
  • A diet plus exercise program that combined both of the above programs.

To measure the results, the researchers assessed pain and function as reported by each patient at the beginning of the study, at six months, and at 18 months. Patients were asked to rate five different pain items on a scale of zero (no pain) to four (extreme pain). They also completed a function questionnaire.

Because joint loading and inflammation play a role in osteoarthritis, the researchers also measured compressive force on the knee joint, and tested the patients’ blood for an inflammation marker.

After 18 months, 399 patients completed the study. The results showed that the diet group and the combination group both lost significantly more weight than the exercise group: the diet group lost an average of 9.5 per cent of body weight, compared to 11.4 per cent of body weight in the combination group and 2 per cent of body weight in the exercise alone group.

The diet and combination groups also had greater improvements in both knee compressive force and inflammation markers than the exercise group.

The combination group had significantly better pain scores compared to the diet or exercise groups after 18 months. In the combination group, 38 per cent of patients reported that they had little to no pain at the end of the study, compared to 20 per cent in the diet group and 22 per cent in the exercise group.

The combination group also had better function and better overall physical health compared to the diet or exercise group.

The study was published in JAMA on Sept. 25, 2013.



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  • A publication of:
  • Women's College Hospital