Magnesium deficiency and vascular complications in type 1 diabetes

You may be able to join if you are aged 18 or older and have lived with type 1 diabetes for at least three years. You will need to be able to make your own decision about taking part and be generally stable on your current diabetes treatments.

Common daily medications like insulin, blood pressure tablets, cholesterol-lowering statins, thyroid hormones, or standard vitamins (like vitamin D or B12) are completely fine. However, you should not be taking multiple other regular prescription medications.

You cannot join if you already have serious diabetes-related complications, such as significant kidney disease, nerve damage, or advanced eye changes. You are also not eligible if you have had heart disease, strokes, blood clots in the past six months, a history of cancer, or if you are pregnant or planning a pregnancy.

Taking part begins with a screening visit at St James's University Hospital in Leeds. A nurse will take a routine blood sample to check your magnesium level. If your level is already normal, your participation ends there. If your magnesium level is low, you will be invited to join the main study, which involves four clinic visits over about six to eight weeks.

During the study, you will take two capsules once a day for two weeks. Half the participants will start with the magnesium supplement, while the other half will start with a dummy pill (placebo); neither you nor the study team will know which you are taking first. After two weeks, you will attend a clinic visit for blood tests and questionnaires, followed by a two-week rest period where you take no study pills. You will then return for your third visit to swap over and take the alternative pill for two weeks. Finally, you will attend a fourth visit for final blood tests and to return your completed questionnaires.