by Nikhil Ramburn and Sat Bir S. Khalsa, Ph.D.
Osteoarthritis (OA) is the most common form of arthritis and is characterized by degenerative joint changes that cause pain and decreased function over time. In addition to loss of joint function and muscle strength, OA symptoms include pain, sleep disturbance which can lead to depression, anxiety and social isolation. Since the most commonly affected joints in OA are the hip and knee joints, which are essential to mobility, arthritis is the most common cause of disability. In fact, approximately 50 million US adults have doctor-diagnosed arthritis with older adults being the most affected. It is noteworthy that non-hispanic blacks and hispanics have worse arthritis impact despite having the same or lower prevalence of arthritis compared to non-hispanic whites. Given the high prevalence and chronic nature of OA, it imposes upwards of $60 billion in healthcare costs and lost productivity in the U.S. The joint degeneration caused by OA is currently irreversible and conventional treatment focuses primarily on symptom alleviation and maximizing joint function.
The common therapies for OA include gentle exercise, heat and cold application, stress reduction, weight management, and pharmacotherapy. Unfortunately, chronic use of pain-relief medication such as acetominophen may have significant side effects on the liver and nonsteroidal anti-inflammatory drugs can impact the stomach and cardiovascular system. On the other hand, appropriate exercise has few negative side effects and is effective at reducing pain, increasing day-to-day function and improving sleep. However, arthritis itself is one of the most common reasons for limiting physical activity. Therefore, in order to improve quality of life, many patients need to find ways to take more responsibility and initiative for their own care, which is why attention is increasingly focused on non-pharmacological interventions that enhance self-care and self-efficacy.
Complementary and integrative approaches include yoga which is known to improve self-efficacy in patients with chronic diseases. A key practice underlying this is the increase in mindfulness and mind-body awareness that is a hallmark of the meditative component of yoga practice, making patients more awareness of the effects of their behaviors on their condition, allowing them to gravitate towards beneficial behaviors and away from negative ones. Furthermore, yoga practices are well known to reduce chronic stress, which not only impact the disorder itself, but can also lead to a cascade of positive outcomes on other comorbid factors of OA such as improved sleep, decreased anxiety and a better ability to detach from the psychological experience of pain. In addition, yoga comes with the benefits of physical exercise exercises including stretching, strengthening and balance and the associated safety component in the ability to adjust pace and intensity.
Existing biomedical research on the efficacy of yoga for OA is promising, and shows some evidence of reduced pain, sleep disturbance, and disability. A recent systematic review published by researchers at the University of Minnesota and Florida Atlantic University in the American Journal of Physical Medicine & Rehabilitation in 2016, examined 12 reports, four of which were randomized controlled trials (RCTs) involving a total of 589 participants with OA-related symptoms. This study found that yoga interventions resulted in reductions in pain, stiffness and swelling but the results on physical function and psychosocial well-being were inconclusive because of the variety of outcome measures used. Of all OA symptoms, yoga seems to have the most positive effect on pain. Not surprisingly, there also seems to be a strong positive relationship between the number of yoga sessions per week and the efficacy of yoga in physical function and emotional well-being in the reviewed studies. This is encouraging since it suggests that the repetition of yoga exercises does not have negative effects on the joints of OA patients and therapeutic yoga programs for OA patients could focus on sustained daily practice as opposed to weekly interventions. In fact, no adverse events were reported. Unfortunately, the majority of the trials were of medium methodological quality and only one trial was of high quality, which prevents us from drawing definitive conclusions at this point.
The first RCT to assess the effect of a yoga intervention on patients with OA of the hands and fingers was published in the Journal of Rheumatology in 1994. Results revealed that the 8-week long, weekly yoga practice yielded significantly greater improvements than the controls’ measures for pain, tenderness and finger range of motion. Another early study, also from 1994, looked at a different type of arthritis, rheumatoid arthritis (RA). This first-ever RCT examining the effects of yoga on RA included 20 participants, in which the intervention group practiced gentle physical postures and breathing techniques whereas the control group received their usual medical treatment. After 3 months, grip strength increased significantly in the yoga group but not in the controls. Both of these early studies were relatively short in duration and underpowered, but they did provide us with the first demonstration of the potential of yoga as an effective therapy for arthritis.
More recently in 2015, the first published study to attempt the design of a yoga strengthening program with functional relevance was conducted by Brenan et al. in Ontario, Canada. This single-group trial included 45 women with knee OA undergoing a yoga program focused on lower extremity strengthening and hip mobility using a variety of squats and lunges. Improvements were observed in all subscales of the Knee injury and Osteoarthritis Outcome Score, such as decreased pain and improved quality of life, with the greatest improvement occurring in the sports and recreation subscale.
Another landmark study published in the Journal of Rheumatology in 2015 is the largest-ever RCT of yoga for OA and RA. Seventy five sedentary adults with RA or knee OA were randomly assigned to 8 weeks of yoga (two 60-min classes and 1 home practice per week) or to a delayed treatment control (waitlist). Moonaz et al. found that yoga was associated with substantial improvements in physical and general health perceptions, pain, energy and mood when compared to the control group. In addition, yoga was not associated with any adverse effects. It is worth noting that this is only the second study in arthritis (of 20 published to date) to include safety data. This preliminary evidence is encouraging and suggests that yoga may help sedentary individuals with arthritis safely increase physical activity and improve physical and psychological health as well as quality of life.
In summary, the current body of evidence points towards decreased pain in yoga program participants and suggests improvements in several risk indices mentioned previously such as mood and quality of life. However, additional studies with active comparison groups in diverse settings and other forms of arthritis are necessary to support these findings and establish the benefits of yoga in relation to traditional exercise. Currently, an ongoing pilot study at the National Institutes of Health Clinical Center, in Maryland is the first to evaluate the feasibility and acceptability of a yoga intervention for arthritis in minority communities. Future studies in diverse settings are vitally important because of the high impact of arthritis in minority populations.