Losing weight and exercise significantly reduces osteoarthritis knee pain and increases arthritic knee function, a new study finds. But this and other studies bear another question: Which is more important — exercise or weight loss?
Researchers from Wake Forest University, led by Dr. Stephen Messier, enrolled 454 elderly adults with significant knee pain resulting from osteoarthritis. They were over 55 years old, lived in an elderly community, and all were obese or overweight, with BMIs ranging from 27 to 41.
The researchers divided the patients into three groups. For 18 months, one group exercised, and another group was given an intensive weight loss diet plan. The third group was given the “intensive” weight loss diet plus exercise.
Those who consumed the weight loss diet plus exercised lost an average of 11.4% of their body weight — over 23 pounds. The diet group lost 9.5% or about 19-1/2 pounds. The exercise-only group dropped only 2% of their weight — about four pounds.
And the reduction in pain and increased knee function increased with the weight loss. Those on the diet plus exercise had significantly less pain. They also had better knee function and faster walking speed compared to the two other groups.
To give you an idea of the differences, the diet plus exercise group reported an average pain score of 3.6 (out of 20), while the diet-only group had a pain score of 4.8 and the exercise-only group had a 4.7 pain score. That means roughly that the diet plus exercise group experienced approximately 25% less pain than did the other two groups.
This is significant when we consider that the difference in weight loss between the diet and exercise group and the diet group was less. This underscores the importance of exercise along with weight loss. And when we consider that the pain scores between the diet group and the exercise group were close, while the weight loss difference between them was so great, this also means the decreases in pain wasn’t all about the weight loss.
The study also found that those with greater weight loss also had lower interleukin 6 levels — meaning they had a reduction in inflammation.
While is more important to osteoarthritis – exercise or weight loss?
This isn’t the first study that revealed the connection between weight loss and arthritis pain — many of these done at Wake Forest. A 2006 study of 87 elderly obese osteoarthritis adults underwent a diet and exercise plan for six months.
The study found that pain reduction was proportionate to the weight loss and body fat reductions. The more the weight loss, the more pain was reduced. Weight loss also corresponded to greater mobility — measured with six-minute walking distance and stair climbing.
But in this study, there was only one weight loss group, and along with the weight loss diet, they exercised three days a week.
The weight loss diet was a 1000 calorie deficit plan — meaning the patients ate 1000 calories less than they burned per day.
The relative importance of weight loss versus exercise is revealed in a 2004 Wake Forest study. In this study, 316 overweight elderly adults over 60 years old were followed for 18 months. They either followed a “healthy lifestyle,” a weight loss diet, exercise plus weight loss diet, or exercise alone. The “healthy lifestyle” served as the control group, as there was no diet or exercise program. Note that neither of the above studies used a control group — that didn’t exercise or diet during the study.
In this 2004 study, once again the diet plus exercise group had significant improvements in walking speed and stair climbing, along with significant pain reduction compared to the other groups.
But in this study, there was little difference between the diet-only group and the control group, even though the diet group still lost a significant amount of weight (5%) compared to the diet plus exercise group (5.7%). The control group only lost 1.2% of their weight.
The results of this study reveal the importance of exercise to osteoarthritis pain and mobility, especially when it comes to the knees, which bear the weight of much of the body. The knees are weight-bearing hinge joints, which means their health is relative to their function. And their function is also relative to not just how much weight they are bearing, but their ability to handle that weight.
And exercise increases their ability to handle the weight load.
Messier SP, Mihalko SL, Legault C, Miller GD, Nicklas BJ, DeVita P, Beavers DP, Hunter DJ, Lyles MF, Eckstein F, Williamson JD, Carr JJ, Guermazi A, Loeser RF. Effects of intensive diet and exercise on knee joint loads, inflammation, and clinical outcomes among overweight and obese adults with knee osteoarthritis: the IDEA randomized clinical trial. JAMA. 2013 Sep 25;310(12):1263-73. doi: 10.1001/jama.2013.277669.
Miller GD, Nicklas BJ, Davis C, Loeser RF, Lenchik L, Messier SP. Intensive weight loss program improves physical function in older obese adults with knee osteoarthritis. Obesity (Silver Spring). 2006 Jul;14(7):1219-30.
Messier SP, Loeser RF, Miller GD, Morgan TM, Rejeski WJ, Sevick MA, Ettinger WH Jr, Pahor M, Williamson JD. Exercise and dietary weight loss in overweight and obese older adults with knee osteoarthritis: the Arthritis, Diet, and Activity Promotion Trial. Arthritis Rheum. 2004 May;50(5):1501-10.
Adams C. Arthritis: The Botanical Solution. Logical Books, 2010.