Study Design and Participants
This study was a randomized single-blind placebo-controlled clinical trial. In the present study, participants include all T2DM patients with vitamin D insufficiency or deficiency were recruited from rofeyde Hospital in Tehran, Iran. This sampling conduct during 1 September 2019 to 25 October 2019.Type 2 diabetes mellitus was diagnosed by a physician with regard to WHO guidelines(13). From 26 October 2019, to January 18, 2020, interventions have been implemented. The presented research is a piece of a larger cohort project concerning examining various treatment for long-term improvement in metabolic syndromes. Because in Iran, the rate of diabetes in women is much higher than men, all participators are women(14)
Inclusion criteria include (1) vitamin D insufficiency or deficiency [ between 10 (ng/mL) to 30 (ng/mL) serum vitamin D], (2) age of 18 to 60 years, and (3) willingness to participations. Exclusion criteria include (1) had psychiatric or neurological disorders, (2) took vitamin D or multivitamin supplements during the last three months, (3) using any illicit substance and alcohol, (4) being in pregnant period, (5) two or more absent in mindfulness groups, (6) using vitamin D supplements over the last 4 months and, (7) Pregnancy or breastfeeding.
Randomization and blinding
Participants were randomly allocated into either intervention or placebo groups (with PC version of random table). All participants blinded to receive vitamin D or placebo. In order to hide the allocation of individuals to groups, closed envelopes containing the code of the assigned group of each person were used along with the number of the person on the envelope.
Regarding 0.05 as type 1 error and 0.2 as type 2 error (with 80%power) based on prior research, 35 patients were required in each group. for covering possible dropouts, sample size 25% increased and reach 45 subjects for each group(15).
The subjects are randomly allocated into the following groups:
- group 1: receiving mindfulness training only
- group 2: receiving mindfulness training + Vitamin D supplement
- group 3: receiving mindfulness training + Placebo
- group 4: receiving vitamin D supplement only
- group 5: placebo only
supplement: In vitamin D groups, patients received a daily 4000 IU oral dosage (two capsules) with 28,000 IU vitamin D weekly for 12 weeks (26 October 2019 until 18 January 2020). This supplement includes fourteen oily drops weekly (sobhan darou, Iranian pharmaceutical company). Placebo (Subhan darou) groups receive totally same drops (without any vitamin D content) and time.
mindfulness: mindfulness consisted of 12 sessions (meeting once a week for 90 minutes) with one psychotherapist and his co-therapist. The intervention protocol was an adaptation of mindfulness to medicine context (MBSR) that introduced by L McCracken(16). Sessions consist of activity-based, interactive, motivational content. this treatment focuses on relaxation (and yoga) exercises and techniques. Also some sessions concentrate on cognitive restructuring, self-compassionate and receiving social support. Other elements of Mindfulness based stress reduction include: Implement mindfulness while breathing, exercise meditation while lying, Tarrying to be in the present moment (Here and now), Ticking off balmy thoughts, Recognizing and accepting unpleasant feeling, emotions and thoughts, Moving from the intrapersonal life to the interpersonal world, Recognizing steady life and planning for a more healthful lifestyle, Organizing for individual care, seeking the right refuge for diabetic problems, planning for solving diabetic problems, and how to moderating life-style in diabetes and vitamin D deficiency. For comparing adherence, audios of sessions were recorded with the permission of all the members. Then a mindfulness psychotherapist checked contents secession. Sessions were divided into 30-minute modules that were taken for adherence checks randomly. The treatment position and the occurrence processes were evaluated. Based on the intervention manual, the modules assessed the adherence level as either enough or not sufficient. The majority of content (93%) was judged as implemented adequately.
Laboratory analyses: ten milliliters of fasting blood sample from every patient was obtained after nine hours of fasting at the start and at the completion of the study. The blood samples stored at −80°C (with ten minutes centrifuging at 3000 rpm) until further analysis with centrifuged to isolate serums. Fasting blood glucose (FBS), measure was performed by spectrophotometry utilizing Pars Azmun kit (Iran)in auto-analyzer equipment (BT3000, Italy).
Insulin resistance: The formula for measurement of Insulin resistance was HOMA-IR (HOMA IR= (Fasting insulin (μU/ml) ×Fasting glucose ((mmol/l) ÷22.5). patients were demanded be fasting for nine hours prior to coming in for blood measuring. To increase the validity of the insulin and glucose outcomes, ere the blood sample, patients filled out a fasting questionnaire that required particular subjects discussing the last time they had consumed any food or liquids. In fact, for assurance that the patients were obeying the fasting contract we used a questionnaire. questions in this scale include common and less commonly considered foods like breath mints, tea, supplements and etc.
Sun exposure time: before implementing intervention and in the post-test by a validated questionnaire the sun exposure rate was assessed. The span of sun exposure was measured by total hours exposing to the sun in the last two week and divided into two.(17).
Energy levels: for assessing nutrients and energy levels, the fourth version Modified Nutritionist software program was used by a trained nutritionist (three-days food recording include one weekend day and two weekdays.
Anthropometric assessments: BMI (Body mass index) by dividing weight (kg) to square height (m2) was calculated. at the baseline and post-test(18).
Physical activity: The brief version of the International Physical Activity Questionnaire (IPAQ) was applied for determining the level of physical activity participants(19).
Cognitive function tasks
three examinations were utilized for evaluation of different aspects of cognitive function:
- Risky decision making: IOWA gambling task analyzing Risky decision-making, impulsivity and attention flexibility. The participators were faced with four cards. The first two cards offer high rewards but sometimes give the participants some huge negative points as well. the last two cards offer fewer amounts of reward but their probability of loss was far fewer than others. The final score is gained by summing up two final cards subtracting from two first cards. we used computer-based version of IOWA (20).
- Intelligence (IQ): for assessing intelligence, we used of Scored General Intelligence Test (SGIT). The purpose of the SGIT is to assess an individual's overall cognitive ability. If the participant receives a score of 25 or below (out of a maximum of 40), it is characteristic of a cognitive problem and further investigation should follow(21).
- Trail Making Test (TMT): TMT has been widely used in neuropsychological evaluation. In condition "B" (that we used in current paper) the participant is to draw lines to attach circled digits and words in an alternating numeric and alphabetic sequence in the Persian language as quickly as possible. TMT reflect a broad variety of cognitive functions including sequencing and shifting, visual search and scanning, flexibility, planning, psychomotor speed, abstraction, attention, and the ability to keep two lines of thought simultaneously. Scoring is based on total time spent(22).
for assessing data SPSS version 26 was employed and we used paired sample t-test, the one-way ANOVA and, post-hoc test (Scheffe). P-values <0.05 were considered statistically significant.