This study is a randomized, double-blind, placebo-controlled trial involving 2,500 individuals aged 40-79 with type 2 diabetes (T2D). The trial includes a 2-year intervention period followed by a 3-year post-intervention follow-up. The primary objective is to investigate (a) the effect of daily supplementation with vitamin D3 (1600 IU) or yeast β-glucan (600 mg) on glycemic control in patients with T2D and (b) whether daily supplementation with vitamin D3 (1600 IU) or yeast β-glucan (600 mg) reduces the predicted 10 year risk of atherosclerotic cardiovascular disease (ASCVD) in patients with T2D. The secondary objectives include evaluating the effects of vitamin D3 or yeast β-glucan supplementation on cardiometabolic risk factors, inflammatory markers, and liver and kidney function indicators, and assessing whether such supplementation reduces the risk of cardiovascular disease, microvascular complications and mortality over the 3-year post-intervention period.
Type 2 diabetes mellitus diagnosed by a physician based on the diagnostic criteria outlined in the Guideline for the Prevention and Treatment of Diabetes Mellitus in China (2024 Edition);
Men or women aged 40-79 years;
Convenient access to the study centers and permanent residence in the vicinity for the next five years;
Voluntary participation and signed written informed consent.
History of clinical cardiovascular disease (including myocardial infarction, treatment or hospitalization for heart failure, stroke, and coronary revascularization) within the past 6 months;
History of severe diabetic microvascular complications (diabetic nephropathy with an estimated glomerular filtration rate (eGFR) < 30 mL/(min·1.73m²), proliferative diabetic retinopathy, confirmed diabetic peripheral neuropathy with abnormal nerve conduction studies or small fiber neuropathy testing);
History of cancer, excluding non-melanoma skin cancer or cancers with a favorable prognosis;
History of kidney stones, hypercalcemia, or hyperparathyroidism;