As yoga has gained popularity as a therapeutic intervention, its safety has been questioned in the lay press. Thus, this review aimed to systematically assess and meta-analyze the frequency of adverse events in randomized controlled trials of yoga. MEDLINE/PubMed, Scopus, the Cochrane Library, and IndMED were screened through February 2014. Of 301 identified randomized controlled trials of yoga, 94 (1975-2014; total of 8,430 participants) reported on adverse events. Life-threatening, disabling adverse events or those requiring intensive treatment were defined as serious and all other events as nonserious. No differences in the frequency of intervention-related, nonserious, or serious adverse events and of dropouts due to adverse events were found when comparing yoga with usual care or exercise. Compared with psychological or educational interventions (e.g., health education), more intervention-related adverse events (odds ratio = 4.21, 95% confidence interval: 1.01, 17.67; P = 0.05) and more nonserious adverse events (odds ratio = 7.30, 95% confidence interval: 1.91, 27.92; P < 0.01) occurred in the yoga group; serious adverse events and dropouts due to adverse events were comparable between groups. Findings from this review indicate that yoga appears as safe as usual care and exercise. The adequate reporting of safety data in future randomized trials of yoga is crucial to conclusively judge its safety.
Keywords: adverse events; complementary therapies; meta-analysis; review; safety; yoga.
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