Osteoarthritis Diminished with Weight Loss
There’s a lot of misinformation going around about osteoarthritis. Much of it pertains to how osteoarthritis develops and what causes it.
And sometimes, simpler solutions work better than more complex ones.
Many have put forth that osteoarthritis is all about hereditary. They see a common connection between family members and figure that osteoarthritis is being inherited from parents or grandparents.
Yet dietary habits also tend to be common among family members. Kids eat the diets of their parents for at least the first decade or two of our lives. Then after we’ve developed those tastes and dietary habits, many continue those dietary habits into their adult years.
For this same reason, obesity tends to also be common among family members. Certain foods and dietary habits – along with lifestyle factors – tend to travel within families.
So is obesity related to osteoarthritis? Many doctors will tell their patients the answer is no. But is that true?
Osteoarthritis incidence linked to obesity
Researchers from the Erasmus University Medical Center in Rotterdam, The Netherlands looked into the connection between obesity and the occurrence of knee arthritis.
The researchers tested 363 women who were middle-aged and either overweight or obese. They followed the women for 30 months, and tested the association of weight loss with osteoarthritis of the knee. The weight losses were achieved through a combination of diet and exercise.
Those who lost either five kilograms (about 11 pounds) or lost five percent of their body weight during the 30 month period were put into one group. The other group – who did not lose weight or lost less weight than this – was compared to the weight loss group on the incidence of osteoarthritis.
Before and after the 30 months, the researchers examined each of the women using X-rays and joint-space narrowing measurements according to the diagnostic criteria of the American College of Rheumatology. In other words, their examinations included both X-ray measurements and physical examinations.
At the end of the study, the researchers found those who lost either 11 pounds or more – or more than 5 percent of their body weight – had a significantly lower incidence of osteoarthritis. The researchers found that 20 percent of the women who didn’t lose weight developed osteoarthritis. And only 15 percent of those who dropped 11 pounds or five percent of their body weight.
This means the risk of osteoarthritis is slashed by a quarter (25 percent) by losing just 11 pounds of five percent of body weight.
The researchers commented:
“15 percent of the women in the group that lost five kilos or five percent of their total weight developed osteoarthritis, while this was 20 percent in the group that lost no weight. Family physicians and physiotherapists can use these results to encourage patients to change their lifestyle. In addition, the study gives useful starting points for further research.”
Remember that we are talking of overweight or obese women who lost only a moderate amount of weight. It would be logical to assume that if they were not overweight or obese, the reduction of osteoarthritis incidence would be even less.
Is it exercise or weight loss?
This is not the only study that has found the association between losing weight and osteoarthritis. And yes, losing more than 11 pounds does have better results. But is it about the exercise or dropping the pounds?
A 2013 study from Wake Forest University Medical School studied 454 men and women with osteoarthritis who were 55 years old or older. They were all overweight and obese, and had a body mass index that ranged from 27 to 41, but 360 of them had BMIs greater than 30. They also had very painful knee osteoarthritis. The study lasted for 18 months.
The participants were divided into three groups. One group underwent an intensive weight loss diet-only plan. Another group did the weight loss diet plus exercise. A third group only did the exercise.
After the 18-months, the researchers found that the diet-only group lost an average of 8.9 kilos (about 20 pounds) – 9.5 percent of their body weight from the beginning of the study. The diet-plus-exercise group lost 10.6 kilos (about 23.5 pounds) – 11.4 percent of their beginning weight.
The exercise-only group lost an average of 1.8 kilos (about 4 pounds) – or 2 percent of their original body weight.
This of course allowed the researchers to compare the effects of weight loss versus exercise. And whether it is the weight loss or the exercise to lose the weight that reduces osteoarthritis.
The researchers found that those in the diet-only group had significantly lower knee force compression compared to the exercise group. The levels averaged 2487 N for the diet-only group, versus 2687 N for the exercise-only group.
In comparison, the diet-only group had a reduced knee joint load by 10 percent (265 N), while the exercise-only group’s knee joint load decreased by five percent (148 N). And the diet-plus-exercise group’s knee joint load decreased by 9 percent (200 N). So the diet-only group’s knee joint load was the lowest.
Inflammation levels – measured by IL-6 levels – were the same between the diet-only group and the diet-plus-exercise groups – at 2.7 pg/mL. These levels were lower than the exercise group, at 3.1 pg/mL.
However, the diet-plus-exercise group experienced less pain – at level 3.6 – than both the diet-only and the exercise-only groups. These had 4.8 and 4.7 levels for pain, respectively.
The diet-plus-exercise group also had better quality of life scores compared to the other two groups.
In terms of mobility, the diet-plus-exercise also won out. The diet-plus-exercise group walked faster and further for the six-minute test. The exercise-only group also walked more than the diet-only group.
Yes, mobility and pain were more improved in the two groups that exercised. And diet plus exercise resulted in the least amount of pain and the greatest mobility. But the researchers found clear evidence that weight loss was the greatest factor in reducing overall symptoms of osteoarthritis. They stated:
“We found significant weight change dose-response effects in knee compressive force, IL-6 [inflammation] level, pain, and function; participants in the high category had significantly lower joint loads, less systemic inflammation and pain, and better function at 18 months.”
The term “dose-response” used above is critical here. It means that the greater the weight loss, the greater the benefit.
Other research confirms its not just about weight-bearing joints
Many might say, ‘well it makes sense if there is less weight compressing the knees.’ Yes, that is certainly a factor. But the research also shows that osteoarthritis in non-weight bearing joints is also reduced by weight loss.
We can look at the Wake Forest study above and see this – as inflammation levels were reduced in the diet-only group more than the other groups. Inflammation levels affect all joints – not just weight-bearing joints.
But there is also more evidence.
The Canadian Agency for Drugs and Technologies in Health – complementary to the FDA in the U.S. – published an extensive review of managing osteoarthritis using weight loss strategies.
The researchers analyzed a number of studies done over recent years that compared weight loss and osteoarthritis incidence. They concluded that weight loss could significantly prevent incidence and reduce symptoms of osteoarthritis. Their findings were not only about weight-bearing joints.
After reviewing the research the scientists stated:
“The association between being overweight or obese and increased stress on weight-bearing joints like the knees and hips seem intuitive, but the exact manner in which excess weight influences osteoarthritis is unclear. However, being overweight has been associated with higher rates of hand osteoarthritis in some studies. Thus, osteoarthritis is considered an active disease process with joint destruction driven by both biomechanical and pro-inflammatory factors.”
The researchers calculated that with each step, just being 10 pounds overweight increases the force on the knees by between 30 and 60 pounds.
After a meta-analysis of the research, they also calculated that a 70-year old man’s risk of osteoarthritis would be cut by 21.5 percent by losing enough weight to fall from the obese category to the obese category. For women, a 70-year-old’s risk would drop by a third – 33 percent – by moving down from obese to overweight.
Note that obesity is defined as a body mass index (BMI) over 30, while overweight is defined as a BMI of between 25 and 29.9. (Here is a chart to calculate your BMI.)
How important is diet and exercise to arthritis?
The evidence is clear that dropping some weight will reduce the pressure on our joints. It will also reduce our levels of inflammation – which directly affects osteoarthritis symptoms and incidence. And it will reduce pain and increase mobility.
Losing weight typically also calls for improved diets – meaning better food choices. Yes, certain foods, as I outline in my book (below), do decrease incidence and symptoms of osteoarthritis.
We can also tease out of the above research that just losing weight is not enough to get the full effect of the weight loss. Exercise further increases mobility and additionally reduces osteoarthritis pain according to the research.
But our choice of diet also directly affects osteoarthritis, say other studies. Take a look at my book for other diet and herbal strategies that have been shown to reduce pain, inflammation and incidence of different forms of arthritis:
Runhaar J, de Vos BC, van Middelkoop M, Vroegindeweij D, Oei EH, Bierma-Zeinstra M. Moderate weight loss prevents incident knee osteoarthritis in overweight and obese females. Arthritis Care Res (Hoboken). 2016 Feb 11. doi: 10.1002/acr.22854.
Erasmus MC. Losing some weight can reduce risk of osteoarthritis by a quarter. Erasmus University Medical Center. Press Release. Accessed April 27, 2016.
Obesity Management Interventions Delivered in Primary Care for Patients with Osteoarthritis: A Review of the Clinical Effectiveness. Ottawa (ON): Canadian Agency for Drugs and Technologies in Health; 2014 Jul 23.
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.