“Effect of Yoga Intervention on Skeletal Muscle Linked Glucose Homeostasis in Pre-Diabetic Individuals: Study Protocol for a Randomized Controlled Trial”

BackgroundThe pre-diabetic stage is important in terms of identi�cation and timely management, as it is reversible. Along with other factors, insulin resistance in skeletal muscle is often considered as primary defect before development of overt hyperglycemia and diabetes. Proven to have many health bene�ts, Yoga has emerged as an effective measure in management of diabetes. As the Yogic postures are relatable to exercises, it was considered for improving skeletal muscle function and reverse the pre-diabetic stage. Methods-The present open, randomized clinical study is planned to evaluate the effect of Yoga interventions on muscle mass, strength, endurance and �exibility which are direct or indirect indicators of fat deposition in skeletal muscles. The study will also explore association between changes in muscle quality/ functionality and glycemic control. With Ethics committee permission, 120 pre-diabetic individuals of either sex between the age group of 35-49 years with a BMI in the range of 25-35 kg/m 2 and family history of T2DM will be recruited in study after obtaining written informed consent. They will be randomly allocated to either Yoga or exercise group by computer generated randomized method in a 1:1 ratio. One group will receive de�ned Yoga interventions, while other group will receive �xed program of physical exercises. Both groups will undergo a training session for a period of 4 weeks under the supervision of a trained instructor, before 12-week study duration. The outcome measures will be parameters related to muscle quality/functionality and glucose metabolism markers. Discussion-Our study aims to study usefulness of Yoga in prediabetic stage on skeletal muscle related glycemic control, which is novel. In addition, the study will generate awareness about pre-diabetes and provide people with active coping skills for reversing it. Trial


Background
Currently diabetes prevalence is rising in India. 1 India ranks second in case of Pre-diabetes, which is condition occurring before diabetes and does not have any symptoms. 2Pre-diabetes stage if identi ed and treated properly can be reverted. 3Hence identifying and treating pre-diabetes becomes important.
Physical activities can be helpful in prevention of such diseases. 4eletal muscle is predominant site for insulin mediated glucose uptake.Skeletal muscle linked glucose homeostasis plays a crucial role in development of Type 2 Diabetes Mellitus.Insulin resistance in skeletal muscle is often considered as primary defect before development of overt hyperglycemia and diabetes. 5The association of diabetes and muscle quality/ functionality is well established.Hence, improvement in muscle quality can be potential therapeutic target for treatment of pre-diabetes and diabetes.
Yoga has many physical and mental health bene ts. 6Yoga is said to be effective in diabetes management and is well reported in diabetic people. 7,8However, the mechanism behind this is still unknown.Physical exercise facilitates skeletal muscle glucose uptake in both insulin independent and insulin dependent ways. 9In this light, we hypothesize that Yoga intervention may also facilitate glycemic control by improving skeletal muscle function.

Study design
The present study is open, randomized clinical study.

Sample size
The screening process will continue until 120 pre-diabetic individuals are selected (60 for Yoga group and 60 for exercise group).This is considering an anticipated drop-out/no-show/refusal of n = 30 to complete the study.

Characteristics of study participants
Participants are eligible to be included in the study if the following criteria are ful lled: 1. Individuals of either sex between the age group of 35-49 years with a BMI in the range of 25-35 kg/m 2 2. Individuals with family history of T2DM

Individuals ready to follow all procedures
Participants are excluded from the study if any of the following criteria are applicable: 1. Known cases of T2DM The Indian Diabetes Risk Score (IDRS), popularly used tool for screening of diabetes in Indian population, has been considered while developing eligibility criteria.

Interventions and Procedures-
After obtaining Institutional Ethics Committee permission, the project will be carried out in 4 steps.
Step 1: Identi cation of pre-diabetics through community screening A community-based screening will be carried out for the above-mentioned eligibility criteria after providing detail information about the study procedures to the potential candidates and documenting their informed consent.
Those individuals ful lling the eligibility criteria will be called to the study site in fasting state for estimation of Fasting plasma glucose (FBG) and Glycosylated hemoglobin (HbA1c).In addition to this, Thyroid Stimulating hormone (TSH) will also be estimated.
The individuals having impaired values for any of these tests (Fasting plasma glucose 100 -125 mg/dL, Glycosylated hemoglobin (5.7-6.4%) will then undergo Oral Glucose Tolerance Test (OGTT) between 140 and <200mg/dl, for further con rmation of pre-diabetic state.
Step 2: Training of Yoga and physical exercise procedures The pre-diabetics so identi ed through community screening will participate in this step.They will be randomly allocated to either Yoga or exercise group.Their family history, medical & surgical history, addictions, diet &psychological stress will be documented.Dietary pattern of the participants will be recorded using Food Frequency Questionnaire, while the stress levels will be evaluated using Perceived Stress Scale.
Following which, they will be randomly divided into 2 groups.The randomization will be done by computer generated randomized method in a 1:1 ratio.The method of block randomization will be used.One group will receive de ned Yoga interventions, while other group will receive xed program of physical exercises.As it is an open labelled study, no blinding mechanism will be followed.
Before carrying out the comparison, both groups will undergo a training session for a period of 1 month (4 weeks) under the supervision of a trained instructor.Since properly carried out Yoga procedures or exercises can only produce optimal effects, the training period is considered essential.During training period, the instructor will assess attendance, motivation and learning abilities of the participants.
The Yoga and exercise programs will be of 60 minutes duration, daily.The components of both programs will be as follows: Yoga protocol 10  Both, the Yoga sessions and the exercise regime will be conducted at Bharati Vidyapeeth, College of Physical Education.There will be 2 batches -morning (6am-8am) and evening (6 pm-8pm) -made available to the participants.They may attend either of the two sessions, as per their convenience.There will be 6 sessions per week.
The following details will be recorded from each participant pre-and post-training period.Step 3: Interventional study of Yoga vis-à-vis exercise The individuals who will successfully complete the training sessions will enter the Step 3 of the study.They will continue following the same program as per the assigned group (Yoga or exercise) for a period of 12 weeks.Like training period, there will be 6 sessions every week, thus 24 sessions per month.The participants need to attend minimum 18 sessions per month.In addition, individuals who will be unable to attend the sessions for more than 4 consecutive days, will be withdrawn from the study.
In addition to clinical and muscle assessment mentioned in Step 2, changes in the dietary pattern (if any) and psychological stress (using Perceived Stress Scale) will be done at this visit and then on monthly basis.Further, this step will involve blood investigations as listed below.All the investigations will be carried out before and after study, except FBG that will be done monthly.The parameters will be estimated using commercially available kits following manufacturer's instructions.
1. Glucose metabolism markers: FBG, Fasting Insulin, HbA1c During the study period, there will be counseling sessions for all participants every month regarding lifestyle modi cations (diet, physical activity and behavior) to motivate them and keep their interest intact in the intervention programs.Apart from this, dietary advice will be given to the participants.
We expect ~30 individuals from each group to complete the study.

Outcome Measures-
The outcome measures will be parameters related to muscle quality/functionality and glucose metabolism markers as explained earlier.

Statistical Considerations
Intention-To-Treat (ITT) analysis will be carried out i.e., data of all recruited participants will be considered.All evaluated parameters will be compared within group and between groups.The data will also be analyzed sex wise (male-female) and age wise (30-≤ 40 years and > 40-49 years).The association of parameters related to muscles will be studied with the parameters of glucose metabolism.Age and sex are the expected confounding variables, which will be taken care of by adjusting data using statistical modeling.As we have adopted block randomization, interim analysis can be done.The statistical analysis is planned as per ITT, hence missing data will be handled by LOCF (Last Observation Carried Forward).
While conducting the study, informed consent will be obtained from all eligible participants willing to participate in the study before any procedures.Each participant will be informed that participation in the trial is voluntary and that they are free to withdraw their participation, without justi cation, from the trial at any time without consequences and without affecting any professional responsibilities.

Data safety and monitoring plan
There is very low risk posed to participants of this study.Thus, the data safety and monitoring will be done by the study team.The spontaneous adverse events will be documented for each participant in the CRF.The funding agency will be responsible for the overall monitoring of the data.

Trial Status
The trial recruitment has begun on 4 th November 2019.The recruitment was stopped after 15 th March 2020 due to COVID-19 pandemic.We anticipate to complete the study by May 2022.

Discussion
The study aims to address one of the most prevalent and detrimental health issues i.e., pre-diabetes.The world staggers with the burden of DM and its complications.Since the pre-diabetic stage is reversible, it becomes crucial to understand more of its mechanisms and eventually management.
We have planned to test the effect of Yoga on insulin resistance and glucose uptake in skeletal muscles of pre-diabetic individuals.Though earlier studies have proven role of Yoga in achieving glycemic control and thereby reversing pre-diabetic stage, the mechanism behind this remains unexplored. 11Certain postulations such as stress reduction, action on Psycho-Neuro-Endocrine axis 12 etc.have been put forward, however the effect on musculoskeletal system has not been elucidated.Since physical activities such as Asana are integral to Yoga, it is likely that they may have effect on intra-myocellular fat deposition that is seen in case of obesity, prediabetes and diabetes.Effect of physical exercise regimen has been well established on the fat deposition in muscles and its related consequences on muscle functionality. 13Hence, we selected exercise as a comparator in the present study.
One of the interesting feature of this study is the focus on lifestyle related interventions, which are cornerstone of lifestyle diseases.Apart from the therapeutic bene ts in pre-diabetes, our study intends to impart awareness about pre-diabetes in community through screening campaigns and also to provide pre-diabetic individuals with active coping skills for reversing it.The other interesting feature of the study is its interdisciplinary nature, wherein the conventional clinical research methodology is applied to traditional science of Yoga.It was challenging in a way to draft a study protocol.Due to complex nature of interventions, de ning various points of the protocol, especially eligibility criteria, compliance, withdrawal criteria, safety assessment etc. were tough.A major issue about the interventions like exercise and yoga is that they cannot be helpful if done in wrong manner.To avoid this, we included a training session of 1-month duration.This approach can help in protocol adherence as well as participant retention during intervention period.
It is expected that the present study will bridge the gap in existing knowledge about Yoga and will prove a step ahead towards evidence based yoga.

1 .
To evaluate the effect of Yoga interventions on muscle mass, strength, endurance and exibility which are direct or indirect indicators of fat deposition in skeletal muscles.2. To study the association between changes in muscle quality/ functionality and glycemic control.Study setting Recruitment of patients, biochemical investigations from serum samples, regular follow up and study documentation will be done at Interactive Research School for Health Affairs (IRSHA), Bharati Vidyapeeth Deemed University, Pune.Muscle assessment test will be carried out at Department of Physiology, Bharati Vidyapeeth Medical College, Bharati Vidyapeeth Deemed University, Pune.
been designed as per Swami Vivekananda Yoga Anusandhana Samsthana (SVYASA) diabetes yoga program.The detailing of all the individual components will be done to the participants.
2. Individuals with known history of any other endocrinological disorders like Hypothyroidism,