What scientific research has been done regarding back pain, joint pain and inflammation in relation to being overweight?
Eric Robertson, P.T., D.P.T.
The link between back pain and obesity is a logical connection, but one that isn't strongly supported by research. Over the years, countless studies have been done to establish the clear link between obesity and back pain, but currently there is only a weak association. Research has been able to show that people who are overweight have increased systemic inflammation, altered postures and reduced activity and available motion at their joints. However, since the exact cause of most low-back pain is hard to determine (85 percent of low-back pain is non-specific in nature), and many researchers often use varied definitions of low-back pain, research studies have not yet been able to tease out the nature of the relationship.
Given the variable findings, some researchers have hypothesized that the relationship between back pain and obesity may be indirect, mediated by factors such as lifestyle and activity level, rather than a direct causal relationship.
Robert Sterling, M.D., orthopedic surgeon and a spokesperson for the American Academy of Orthopaedic Surgeons (AAOS)
Weight clearly has an effect on the development of arthritis. Research has shown that the incidence of knee arthritis is increased in individuals with a body mass index over 30 ("obese"). Radiologic studies have also shown increased spinal arthritis in obese individuals. While typically thought of as a "wear and tear" phenomenon, recent studies suggest that this explanation greatly oversimplifies the problem. There is likely a complex interaction of genetics, anatomy (alignment of the joints) and biology that leads to the development of arthritis.
If you lose weight will it improve your quality of life and reduce pain?
Nathaniel Tindel, M.D.
While we know that significant improvement in quality of life is achieved with reduction in body weight, there are no hard numbers to quote to our patients. What we do know is that patient self-satisfaction improves significantly and continues to do so with further weight reduction. This is a situation where a little is good and a lot is better.
Robert Sterling, M.D.
In one recent report of a weight-loss program for obese individuals with symptomatic osteoarthritis of the knee, weight-loss patients (average loss 8.7 percent) had better six-minute walking distance, faster stair climbing and an improved score on the Western Ontario and McMaster Universities Osteoarthritis Index (a validated measure of pain and function in individuals with lower-extremity arthritis). The Framingham osteoarthritis study also found an increase in the incidence of knee osteoarthritis of 1.4 times for every 10-pound weight gain over time.
Eric Robertson, P.T., D.P.T.
You can gain some knowledge from research assessing the effects of bariatric surgery for weight loss. In one trial, the group of subjects reduced their BMI from 49 to around 32. During this time, their reports of pain and functional scores related to low-back pain reduced about 75 percent. Other studies have demonstrated similar results and, anecdotally, many patients whom I've observed to lose significant amounts of weight have reported dramatic reductions in back pain. One caveat is that you may need to lose enough weight to significantly affect posture before you realize meaningful reductions in back pain.