Does the Location of Yoga Research Matter? What You Need to Know
More than 36 million American adults reported practicing yoga in 2015. Of that number, two-thirds indicated that they use yoga to improve their health status. Now more than ever people rely on the yoga research to provide a fair and unbiased account of the effects of yoga on a plethora of physical and psychological conditions. But what if that information is skewed?
A new study published in Contemporary Clinical Trials suggests that randomized controlled trials conducted in India are roughly 25 times more likely to reach a positive conclusion compared to studies conducted elsewhere. This has significant implications for yoga educators, therapists and practitioners who are looking to the yoga research to understand what works and for whom.
Although Indian yogis have been studying the effects of yoga for centuries, it was not until the early 20th century that Indian scientists began adopting what could be considered more Western forms of experimental and translational research. This has led to the proliferation of numerous scientific journals that have published upwards of several thousand studies of the effects of yoga for a breadth of physical and psychological issues. Indeed, almost half of the published studies of yoga’s effects originated in India.
Comparing Indian to Non-Indian Yoga Research
While this is not a problem in and of itself, there has been a long standing concern that studies originating in Asian countries have a greater likelihood of reporting positive findings than those from Western nations. This has the potential to mistakenly skew our perceptions of yoga’s effects in the positive direction, leading us to overestimate the therapeutic effects of the practice.
To address this concern, a group of German researchers conducted a systematic review of the published yoga research. They were particularly interested in examining whether the conclusion of a study was associated with its country of origin, and the type of journal that the study was published in.
Researchers focused their attention on randomized controlled trials (RCTs)—studies in which participants are randomly assigned to either an active yoga condition, or to one or more groups that do not receive a yoga intervention. RCTs are considered by many to be the gold standard of research design as they reduce the likelihood that results are influenced by arbitrary factors.
Studies published in any language prior to February 2014 that included comparison of a yoga to a non-yoga intervention were considered. There were no restrictions on the tradition of yoga used, or the type, frequency, duration, type of participant or nature of condition being “treated.”
A total of 306 RCTs were evaluated in the systematic review. Of these studies, 131 were from India and 175 originated in other countries. Eighty-four of the articles were published in journals that specialized in complementary and alternative medicine (CAM).
An individual who was unaware of the nature or origin of the studies was asked to rate each of the study’s stated conclusions as either positive (authors stated that yoga was superior to the non-yoga control group in alleviating symptoms), neutral (no definitive statements as to yoga’s usefulness regarding a particular condition), or negative (yoga was unhelpful in dealing with a specific condition and not as effective as a control group intervention).
Indian Research Findings Significantly More Positive
Positive conclusions were reached in 91% of studies. As anticipated, studies conducted in India had approximately 25 times the odds of reporting a positive conclusion than those studies originating elsewhere. There were no differences in positive findings between research published in CAM specialty journals and others.
Researchers conducting the systematic review of the yoga research attributed these results to a number of potential explanations.
Yoga interventions conducted in India may be more effective because yoga is an indigenous practice and embedded in Indian culture and tradition. As such, participants may experience greater benefits than those in other countries. Further, Indian yoga interventions are often of greater intensity than those conducted elsewhere, and it is possible that instructors possess greater skill given the depth of yogic tradition in India.
Indian researchers may be less likely than those from other regions to publish negative effects. This type of publication bias is not unique to India or to yoga. Many researchers are reluctant to publicly acknowledge negative or inconclusive results due to potential ill effects on their careers or programs of research. This is not only creates a biased account of the effects of a particular technique, but also denies the field the chance to learn from what does not work. This is indeed a huge missed opportunity and one that undermines the field of yoga at large.
As discussed my recent article, “Why Yoga Research Has a Long Way to Go,” yoga research has historically suffered from a dearth of funding, and therefore subject to other issues that have resulted in methodological limitations and inconsistencies that require us to interpret the existing yoga research with caution. This is a global phenomenon and one that will hopefully be remedied as more attention is paid to yoga as a viable and important contributor to the field of complementary medicine.
Results from this systematic review suggest that it is important to interpret the results of Indian studies with caution. In general a great deal more research is needed before we can be confident that yoga interventions can reliably reduce symptoms for any given condition.
More about yoga reseach with B Grace Bullock: What Makes a Good Yoga Study? Some of the Basics
B Grace Bullock, PhD, E-RYT 500 is a psychologist, research scientist, educator, author, yoga and mindfulness expert and creator of BREATHE: 7 Skills for Mindful Relationships. Her mission is to reduce stress, increase health and wellbeing and improve the quality of relationships. She offers classes, workshops, writing and research that combine the wisdom of applied neuroscience, psychophysiology, psychology and contemplative science and practice. Her goal is to empower individuals, groups, leaders and organizations to reduce chronic stress and increase awareness, attention, compassion, mindfulness and effective communication to strengthen relationships, release dysfunctional patterns and unlock new and healthy ways of being. Dr. Bullock is a Certified Viniyoga Therapist and Faculty at the Integrated Health Yoga Therapy (IHYT) Training program. She is the former Senior Research Scientist at the Mind & Life Institute and former Editor-in-Chief of the International Journal of Yoga Therapy. For more information see www.bgracebullock.com
Cramer, H., Lauche, R., Langhorst, J. & Dobos, G. (2015). Are Indian yoga trials more likely to be positive than those from other countries? A systematic review of randomized controlled trials. Contemporary Clinical Trials. http://dx.doi.org/10.1016/j.cct.2015.02.005.