Effects of Vitamin D and Fish Oil on the Kidney in Hypertensives

Brigham and Women's Hospital, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

The VITamin D and OmegA-3 TriaL (VITAL; NCT 01169259) is an ongoing randomized clinical trial in 25,875 US men and women investigating whether taking dietary supplements of vitamin D3 (2000 IU) or omega-3 fatty acids (Omacor (R) fish oil, 1 gram) reduces the risk of developing cancer, heart disease, and stroke in people who do not have a prior history of these illnesses. The VITAL Kidney Function in Hypertension ancillary study will evaluate the effects of vitamin D or omega-3 fatty acids on kidney function among participants with baseline hypertension.

This ancillary study to the VITamin D and OmegA-3 TriaL (VITAL) will test whether vitamin D3, omega-3 fatty acids, or both prevent the development and progression of kidney disease in participants with hypertension. Persons with hypertension are at high risk of kidney disease. Vitamin D and omega-3 fatty acids are promising interventions for kidney disease prevention and treatment, based on results of animal-experimental models and early human studies. Because these interventions are relatively safe, inexpensive, and widely available, they may offer opportunity to substantially reduce the burden of kidney disease in large populations. This VITAL ancillary study will test whether vitamin D3 and/or omega-3 fatty acids prevent loss of glomerular filtration rate, over 4 years of therapy. In VITAL, 25,875 participants have been randomly assigned in a 2x2 factorial design to vitamin D3 (cholecalciferol) 2000 IU daily versus placebo, and to eicosapentaenoic acid 465 mg plus docosahexaenoic acid 375 mg daily versus placebo, and followed for a mean of 5 years to assess effects on cardiovascular disease and cancer events. This ancillary study will identify and recruit a sub-cohort of VITAL participants with hypertension at baseline and ascertain effects of study interventions on glomerular filtration rate in this group. Blood samples will be collected at year 4 simultaneously for measurement of estimated glomerular filtration rate (using serum creatinine and cystatin C) and other relevant biomarkers. This VITAL ancillary study is designed to determine whether vitamin D3 and/or omega-3 fatty acids have causal and clinically relevant effects on the development and progression of kidney disease in hypertensives.

Dietary Supplement: Vitamin D Vitamin D3 (cholecalciferol), 2000 IU per day. Drug: Omega-3 fatty acids (fish oil) Omacor, 1 capsule per day. Each capsule of Omacor contains 840 milligrams of marine omega-3 fatty acids (465 mg of eicosapentaenoic acid [EPA] and 375 mg of docosahexaenoic acid [DHA]).

Dietary Supplement: Vitamin D Vitamin D3 (cholecalciferol), 2000 IU per day. Dietary Supplement: Fish oil placebo Fish oil placebo

Drug: Omega-3 fatty acids (fish oil) Omacor, 1 capsule per day. Each capsule of Omacor contains 840 milligrams of marine omega-3 fatty acids (465 mg of eicosapentaenoic acid [EPA] and 375 mg of docosahexaenoic acid [DHA]). Dietary Supplement: Vitamin D placebo Vitamin D3 placebo

Dietary Supplement: Vitamin D placebo Vitamin D3 placebo Dietary Supplement: Fish oil placebo Fish oil placebo

Omacor, 1 capsule per day. Each capsule of Omacor contains 840 milligrams of marine omega-3 fatty acids (465 mg of eicosapentaenoic acid [EPA] and 375 mg of docosahexaenoic acid [DHA])

Inclusion Criteria: Participants in VITAL (NCT 01169259) with a self-reported physician diagnosis of hypertension are eligible to participate in this ancillary study Exclusion Criteria: Diagnosis of diabetes mellitus