Yoga as a Therapeutic Intervention: A Bibliometric Analysis of Published Research Studies from 1967 to 2013

Abstract

Objective: A comprehensive bibliometric analysis was conducted on publications for yoga therapy research in clinical populations.

Methods: Major electronic databases were searched for articles in all languages published between 1967 and 2013. Databases included PubMed, PsychInfo, MEDLINE, IndMed, Indian Citation Index, Index Medicus for South-East Asia Region, Web of Knowledge, Embase, EBSCO, and Google Scholar. Nonindexed journals were searched manually. Key search words included yoga, yoga therapy, pranayama, asana. All studies met the definition of a clinical trial. All styles of yoga were included. The authors extracted the data.

Results: A total of 486 articles met the inclusion criteria and were published in 217 different peer-reviewed journals from 29 different countries on 28,080 study participants. The primary result observed is the three-fold increase in number of publications seen in the last 10 years, inclusive of all study designs. Overall, 45% of the studies published were randomized controlled trials, 18% were controlled studies, and 37% were uncontrolled studies. Most publications originated from India (n=258), followed by the United States (n=122) and Canada (n=13). The top three disorders addressed by yoga interventions were mental health, cardiovascular disease, and respiratory disease.

Conclusion: A surge in publications on yoga to mitigate disease-related symptoms in clinical populations has occurred despite challenges facing the field of yoga research, which include standardization and limitations in funding, time, and resources. The population at large has observed a parallel surge in the use of yoga outside of clinical practice. The use of yoga as a complementary therapy in clinical practice may lead to health benefits beyond traditional treatment alone; however, to effect changes in health care policy, more high-quality, evidence-based research is needed.

FIG. 1.

The pie chart shows the proportion of all publications (n=486) reporting randomized controlled trials (RCTs), nonrandomized controlled studies, and uncontrolled studies (i.e., no control group).

FIG. 2.

The bar chart shows the percentage of publications by journal type and study design. Duplications by study design were excluded (n=27). CAM, complementary and alternative medicine.

FIG. 3.

Histogram of sample size by study design. Total sample size for each publication is plotted (bin size=25). Publications with duplicate sample size were excluded (n=59).

FIG. 4.

Number of publications for every 5-year increment (with the exception of 1967–1973) for all journals and for each study design.

FIG. 5.

Number of publications by region.

FIG. 6.

Number of publications categorized into broad disorders by study design. Publications with multiple disorders were excluded (n=9).