Can Calcium and Vitamin D reduce diabetes risk in people at high risk?

This study is testing whether taking vitamin D and calcium supplements can lower the risk of developing type 2 diabetes in people who are already at high risk. Type 2 diabetes is Australia's fastest-growing chronic disease. Researchers have noticed that low vitamin D levels may be linked to a higher chance of developing diabetes. Over 6 months, participants will take either vitamin D and calcium supplements or placebos (inactive pills) to find out if the supplements reduce diabetes risk and improve heart health. You may be eligible if: - You are 18 years or older - You are overweight or obese (BMI between 25 and 35 kg/m²) - You have been found to have pre-diabetes (impaired fasting glucose or impaired glucose tolerance) - You are deficient in vitamin D You may NOT be eligible if: - You are pregnant or breastfeeding - You have kidney disease, cirrhosis, or malabsorption problems - You have high blood calcium or a history of kidney stones - You have an active inflammatory disease - You have recently changed diabetes-related or weight medications - You have had or are planning bariatric (weight loss) surgery - Your weight has changed by more than 5% in the past 3 months Talk to your doctor about whether this trial might be right for you.