Yoga and Its Effect on Glycemic Control and Oxidative Stress in People with Type 2 Diabetes in A Randomized Trial: Systematic Review and Meta- Analysis

Background:b> Yoga is being evaluated for its potential beneficial effect on people with type 2 diabetes(T2DM) as an adjuvant therapy by researchers around the globe. Few systematic reviews and meta-analyses previously performed have indicated mixed effect of yoga. In this review we aimed to evaluate further whether yoga has an impact on metabolic parameters in people with T2DM.

Methods: Systematic review and meta-analysis of randomized controlled trials (RCTs) comparing the practice of any type of yoga, asanas or pranayamas vs. standard care in adults with T2DM. The primary outcome was change in fasting plasma glucose and glycated haemoglobin (HbA1c). The secondary outcome was serum lipid profile and oxidative stress. The electronic databases such as, Cochrane CENTRAL, Scopus, Medline, Embase and CINAHL were searched from the year 1990 to August 2015 to find out the studies done on yoga as per the eligibility criteria. Meta-analysis was conducted using the inverse variance method of analysis with random-effect models with checks of heterogeneity using the I2 test.

Results:b> From a total of 788 articles screened, nine RCTs were included involving 788 participants. In five trials yoga group had a significant reduction in HbA1c ( mean difference(MD) -0.51% , 95%CI -0.57 to -0.44, P =0.006, fasting plasma glucose (mean difference(MD) as -25.2 ,95 % CI -25.31 to -25.2mg/dl, P <0.00001, and serum LDL (mean difference(MD) -26.8mg/dl , 95% CI -42.1 to -11.5 mg/dl, p =0.0006), HDL (mean difference(MD) 6.8 mg/dl (95% CI 4.8 to 8.7, p <0.00001), total cholesterol (mean difference(MD) -33.3 mg/dl (95% CI -35.8 to -30.8, p <0.00001), triglycerides (mean difference(MD) 39.4 mg/dl( 95% CI -50.0 to -28.8, p <0.00001), cortisol (mean difference(MD) -5.5 μg /l ( 95% CI -7.1 to -4.0, p <0.00001), malondialdehyde (mean difference(MD) 16.6 nanomol/dl (95%CI -22.0 to -11.2, p<0.00001).

Conclusion:The results from the available trials indicate that yoga may be a potentially beneficial intervention for improving glycemic control, lipid profile and indicators of oxidative stress in people with T2DM. Further studies are required to corroborate yoga’s effect on other outcomes such as psychosocial profiles.

Keywords: Yoga; Systematic review; Meta-analysis; T2DM; Stress

Abbreviations: BMI: Body Mass Index; CAM: Complementary and Alternative Medicine; FBG: Fasting Blood Glucose; HDL: High Density Lipoprotein; LDL: Low Density Lipoprotein; MENA: Middle East and North Africa; MDA: Malondialdehyde; RCT: Randomized Controlled Trials; T2DM: Type 2 Diabetes Mellitus