Efficacy of yoga based lifestyle in intervention on acute phase insulin release in pre-diabetes : Randomized active control trial

Abstract

BACKGROUND Pre-diabetes or impaired fasting glucose is a preliminary stage for the onset of Type 2 Diabetes with fasting glucose in the range of 100-125 mg/dl, post prandial blood glucose 140-199 mg/dl and glycated hemoglobin ranging between 5.6-6.4%. Triggers for pre diabetes are defective Glucose stimulated insulin release, insulin secretory defect and impaired incretin effect, all of which adversely affect the beta cell activity thereby hiking blood glucose beyond normal threshold. However, one of the not widely known reasons is abolished acute phase insulin release also known as first phase insulin release. Post glucose uptake, insulin is released in two phases: acute phase and sustained phase. Among individuals with normal glucose tolerance, during the acute phase, insulin level spikes to a maximum from 5 th to 10 th minute, after which the level falls back to baseline reading. This is followed by the second phase also known as sustained phase insulin release (SIR) where the increase is more gradual and lasts to 2 or in certain cases even for 3 hours. Abolished acute phase insulin release when left unaddressed results in pre-diabetes and within 1-10 years leads to the onset of type 2 diabetes mellitus (T2DM). Also, by the time individual gets detected with T2DM several of the known complications of diabetes would have set in. Previous studies have shown significant reduction in risk of pre-diabetes converting to full blown diabetes with Yoga. Also improved Vagal tone and incretin effect have been associated with improved insulin acute phase insulin secretion. This study outlines the comparative effect of yoga and physical activity on improving Acute Phase Insulin Release (AIR) in pre-diabetes. AIM AND OBJECTIVES The aim of this study was to assess the impact of yoga and walking on acute phase insulin release and the mechanism of action of the interventions on pre-diabetes reversal or management THE OBJECTIVES WERE a. To examine the impact of yoga and walking on acute phase insulin release and related hormonal measures like C Peptide, GLP-1 and pro-insulin vi b. To understand the mechanism of action of Yoga on the AIR c. To know how Yoga and walking helps in reversing pre-diabetes to normal METHOD Participants A total of seventy-five (n=75) adults with pre-diabetes were identified from among interested volunteers (N=307) screened from urban part of Bangalore, India. Screening for pre-diabetics was done based on the Fasting Blood Glucose (FBG), Body mass index and Indian Diabetes Risk Scores (IDRS). Out of the total identified people with pre-diabetes (n=75), more than half of the adults (n=42) fitting into the inclusion exclusion criteria who had consented to take part were randomized and recruited into Yoga (n=20) and active control group (n=22). Design Randomized active control trail Assessments Oral glucose tolerance test was performed at baseline and post the intervention period. Variables assessed before and after the intervention are: • Serum Insulin and c-peptide (measured at 10 time points at regular intervals from 0 th minute to 90 th minute (0,3,5,7,10,15,30,45,60 and 90 th minute) post oral intake of diluted (75grams of glucose in 220ml of water) glucose). • Serum GLP-1 (at 0 th minute blood sample) • Pro-insulin (at 0 th minute blood sample) • Heart rate variability • Kidney function test, • Liver function test • Lipid profile • Psychological variables: Perceived stress scale (PSS-10), patient health questionnaire (PHQ-9) and MOS sleep quality index (MOS-SS-12). vii Intervention Standardized Integrated Approach of Yoga Therapy (IAYT) module for type 2 diabetes was administered for 1 hour a day for 5 days a week for 3 months for participants in the Yoga group (YG). Active control group (CG) were monitored for 45 minutes of moderate pace walking a day for five days (220 minutes a week) for three months. RESULTS More than half (n=13, 68%) of the subjects of Yoga group had come back to normoglycemia while a little more than one-fourth (n=5, 26%) remained as pre-diabetes and, one of the subjects (n=1, 5.3%) had turned to type 2 diabetes post the intervention period. In the Control group, only one subject (n=1, 5%) returned to normoglycemia. While less than half of the subjects could retain their glycemic status in pre-diabetes range (n=10, 45%), more than half of the subjects (n=9, 50%) turned out to be type 2 diabetes during the post interventional assessment. In addition, this study showed revival of abolished acute phase insulin release (at 10 minute), which was supported by a comparable pattern of change in the of C Peptide levels. The parameters of HRV (heart rate, RMSSD, HF, LF, LF/HF) when correlated with perceived stress, showed a significant correlation of data of both the yoga and walking group. The correlation result showed the impact of reduced stress on improved function of cardiac autonomic variables. However, the change was found to be much better in yoga group than among the individuals of control group. Also, Yoga group participants showed a significant improvement in the GLP-1, pro-insulin and proinsulin/insulin ratio providing further credence to observed improvement in insulin levels, indicating the mechanism by which the yoga worked. Further supporting evidence was also implied from improved mood and sleep quality assessments in the subjects of Yoga group. Nineteen in yoga and 20 in active control group completed the study. CONCLUSION Yoga intervention was found effective than walking in preventing or delaying the conversion of pre-diabetes to diabetes. Also, all the parameters related to insulin dynamics showed significantly favorable change along with autonomic assessments and stress levels in the Yoga group. This is the first study elucidating the mechanism of action of Yoga in preventing conversion from pre-diabetes to diabetes at the same time providing assurance viii for adopting Yoga for either remission of pre-diabetes or prevention and delaying the onset of type 2 diabetes. Keywords: Pre-diabetes; Yoga; Walking; Acute phase insulin release, Impaired fasting glucose; BMI; diabetes prevention; prevalence; Diabetes risk reduction; Prevention of diabetes Abbreviations: PDM: Pre-diabetes; T2DM: Type 2 Diabetes Mellitus; BMI: Body Mass Index; I: Insulin; CP: C-peptide