The goal of this randomized, double-blind, placebo-controlled, 6-month supplementation study in individuals with type 2 diabetes is to investigate whether taking daily dietary supplements of vitamin D3 (1600 IU) or prebiotics (inulin, 10 gram) has beneficial effects on cardiovascular disease risk factors.
The goal of this randomized, double-blind, placebo-controlled trial, with a two-by-two factorial design in individuals with type 2 diabetes (T2D) is to investigate whether taking daily dietary supplements of vitamin D3 (1600 IU) or prebiotics (inulin, 10 gram) has beneficial effects on cardiovascular disease (CVD) risk factors. About 200 subjects with T2D will be included in this study. All participants will provide written informed consent before randomization. Eligible participants must have no history of cancer, macrovascular or microvascular complications at trial entry, and they are required to agree to limited use of vitamin D, prebiotics, probiotics, or synbiotic supplementations, as well as to convenient access to study centers. Safety exclusions include renal failure or dialysis, cirrhosis, history of hypercalcemia, or other conditions that would preclude participation. Eligible participants will be assigned by chance to one of four groups: (1) daily vitamin D3 (1600 IU) and prebiotics (10 grams); (2) daily vitamin D3 (1600 IU) and prebiotics placebo (10 grams); (3) daily vitamin D3 placebo and prebiotics (10 grams); or (4) daily vitamin D3 placebo (1600 IU) and prebiotics placebo (10 grams). Randomization will be computer-generated within sex and age groups. During the run-in period, baseline questionnaires will be designed to collect data on sociodemographic factors, lifestyle habits, health status, and medical conditions, and participants will undergo physical measurements at baseline. Blood, urine, and faeces samples will also be obtained at study centers. Participants in all groups will be required to take two capsules each day, containing either vitamin D3 or vitamin D3 placebo, as well as a strip of prebiotics powder (10 g per strip, brew with warm water) or prebiotics placebo. Participants will receive their capsules and powder at study centers each month. Participants will complete follow-up questionnaires, including information on adherence to trial regimens, outside use of supplementations, development of major illnesses, and potential side effects of the trial agents, at 3 months and 6 months after randomization. Physical measurements and collection of biological samples will be conducted at study centers 6 months after randomization. The primary outcomes, including glycated hemoglobin (HbA1c) and blood lipids (such as total cholesterol, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol), will be measured using blood samples. The data will be collected and analyzed.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
QUADRUPLE
Enrollment
190
Vitamin D3 (cholecalciferol), 1600 IU per day.
Prebiotics (inulin), 10g per day.
Vitamin D3 placebo
Bao'an Center Hosipital of Shenzhen
Shenzhen, Guangdong, China
School of Public Health, Tongji Medical College, Huazhong University of Science and Technology
Wuhan, Hubei, China
Glycated hemoglobin (HbA1c)
Concentration of HbA1c, measured in the percentage of hemoglobin
Time frame: 6 months
Concentration of blood lipids
Concentration of blood lipids (total cholesterol, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol), measured in mmol/L
Time frame: 6 months
Metagenomic analysis of the gut microbiota
The diversity of the gut microbiota will be assessed by high-quality whole-metagenomic sequencing
Time frame: 6 months
Concentration of fasting glucose
Concentration of fasting glucose, measured in mmol/L
Time frame: 6 months
Concentration of fasting insulin
Concentration of fasting insulin, measured in milli-International unit/L
Time frame: 6 months
Systolic and diastolic blood pressure
The level of systolic blood pressure and diastolic blood pressure, measured in mmHg
Time frame: 6 months
Estimated glomerular filtration rate (eGFR)
Calculating the level of eGFR using Chronic Kidney Disease Epidemiology Collaboration equation
Time frame: 6 months
Concentration of C-reactive protein (CRP)
Concentration of CRP, measured in mg/dL
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Prebiotics placebo, 10g per day.
Time frame: 6 months
Concentration of procalcitonin
Concentration of procalcitonin, measured in pg/mL
Time frame: 6 months
Concentration of interleukin-6 (IL-6)
Concentration of IL-6, measured in pg/mL
Time frame: 6 months
Concentration of serum 25(OH)D
Concentration of serum 25(OH)D concentrations, measured in nmol/L
Time frame: 6 months
Body weight
Weight in kilograms
Time frame: 6 months
Waist circumference
Waist circumference in centimeters
Time frame: 6 months
Hip circumference
Hip circumference in centimeters
Time frame: 6 months