Vitamin D and the Health of Blood Vessels in Kidney Disease

Most people living in Canada do not receive enough vitamin D from the sun or from the food they eat. When a person has kidney disease this is a particular problem as kidney disease stops what little vitamin D we do have being activated in the body. Low levels of activated vitamin D causes a domino effect with calcium and phosphate and all the hormones that control calcium and phosphate. Some people believe that this imbalance damages the blood vessels causing them to become stiff and inflexible (arterial stiffness) and this in turn could cause heart disease. In addition there are two different types of vitamin D that can be prescribed and it is currently not known whether there is any difference between the two types of vitamin D and the effect they have on the blood vessels.

The purpose of this study is to investigate whether providing vitamin D as a medication can have a direct affect on the stiffness of the blood vessels. The findings of this study will help both physicians and dietitians decide whether Vitamin D therapy is beneficial to patients and should help decide which type of Vitamin D is best to give to people with chronic kidney disease (CKD).

• Dietary Supplement: Dietary supplement
  Placebo given orally 3xweek for six months
• Dietary Supplement: Vitamin D
  5000 IU vitamin D given orally 3xweek for six months
• Dietary Supplement: Vitamin D
  0.5ug 1,25 vitamin D given orally 3xweek for six months

• Active Comparator: 1.

  1,25 Vitamin D (0.50ug *3 per week)

  This is a prospective randomized double blind placebo controlled study of 125 stable CKD subjects examining the impact of vitamin D supplementation (1,25 vitamin D or 25 vitamin D formulations) compared to placebo on arterial stiffness and other parameters of vascular health

  Intervention: Dietary Supplement: Vitamin D
• Active Comparator: 2.

  25 Vitamin D (5000IU * 3 per week)

  This is a prospective randomized double blind placebo controlled study of 125 stable CKD subjects examining the impact of vitamin D supplementation (1,25 vitamin D or 25 vitamin D formulations) compared to placebo on arterial stiffness and other parameters of vascular health

  Intervention: Dietary Supplement: Vitamin D
• Placebo Comparator: 3.
  Placebo given orally 3xweek for six months
  Intervention: Dietary Supplement: Dietary supplement

• Levin A, Perry T, De Zoysa P, Sigrist MK, Humphries K, Tang M, Djurdjev O. A randomized control trial to assess the impact of vitamin D supplementation compared to placebo on vascular stiffness in chronic kidney disease patients. BMC Cardiovasc Disord. 2014 Nov 7;14:156. doi: 10.1186/1471-2261-14-156.
• Levin A, Tang M, Perry T, Zalunardo N, Beaulieu M, Dubland JA, Zerr K, Djurdjev O. Randomized Controlled Trial for the Effect of Vitamin D Supplementation on Vascular Stiffness in CKD. Clin J Am Soc Nephrol. 2017 Sep 7;12(9):1447-1460. doi: 10.2215/CJN.10791016. Epub 2017 May 26.

Inclusion Criteria:

• patients with an estimated glomerular filtration rate (eGFR) between 15 - 45 ml/min, and <2ml/min change in glomerular filtration rate (GFR) over the past 6 months
• treated with maximal conventional cardiovascular disease (CVD) risk reduction medications

Exclusion Criteria:

• patients with estimated glomerular filtration rate (eGFR) change of >2.1 ml/min over the past 6 months
• those who have terminal malignancies
• those with planned transplant within 6 months, or who are likely to commence renal replacement therapy (dialysis) within the 6 months after enrolment
• those with active infections or active inflammatory diseases (Systemic Lupus Erythematosus (SLE), vasculitis)
• those who refuse to give informed consent

• The Kidney Foundation of Canada
• Pfizer