Trial Information

Vitamin D and Omega-3 Trial to Prevent and Treat Diabetic Kidney Disease

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 diabetic kidney
disease (DKD). Persons with diabetes are at high risk of kidney disease. In 2005-2008, the
prevalence of DKD among people with type 2 diabetes in the United States was 34.5%.
Moreover, from 1988-1994 to 2005-2008, the prevalence of DKD in the United States grew 34%
to 6.9 million people. DKD is both the leading cause of end stage renal disease in the
developed world and a potent amplifier of cardiovascular disease risk.

Vitamin D and omega-3 fatty acids are promising interventions for DKD 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 DKD in large populations. This VITAL
ancillary study will test whether vitamin D3 and/or omega-3 fatty acids prevent progression
of albuminuria and loss of glomerular filtration rate, two complementary manifestations of
DKD, over 3 years of treatment.

In VITAL, 20,000 participants will be 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 diabetes at baseline and
ascertain effects of study interventions on albuminuria and glomerular filtration rate in
this group. First morning voids will be collected at baseline and year 3 for measurement of
urine albumin-creatinine ratio. Blood samples will be collected 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 DKD.