ASN's Mission

ASN leads the fight to prevent, treat, and cure kidney diseases throughout the world by educating health professionals and scientists, advancing research and innovation, communicating new knowledge, and advocating for the highest quality care for patients.

learn more

Contact ASN

1401 H St, NW, Ste 900, Washington, DC 20005


The Latest on Twitter

Kidney Week

Abstract: FR-OR138

Effects of Vitamin D and Omega-3 Fatty Acid Supplementation on Kidney Function and Damage in Type 2 Diabetes

Session Information

  • High-Impact Clinical Trials
    November 08, 2019 | Location: Ballroom C, Walter E. Washington Convention Center
    Abstract Time: 03:45 PM - 04:00 PM

Category: Diabetic Kidney Disease


  • de Boer, Ian H., Division of Nephrology and Kidney Research Institute, University of Washington, Seattle, Washington, United States
  • Zelnick, Leila R., Kidney Research Institute, Seattle, Washington, United States
  • Hoofnagle, Andrew N., University of Washington, Seattle, Washington, United States
  • Thadhani, Ravi I., Cedars-Sinai, Los Angeles, California, United States
  • Manson, Joann E., Brigham and Women's Hospital, Harvard, Boston, Massachusetts, United States

Group or Team Name

  • VITAL-DKD Research Group

Vitamin D and omega-3 fatty acid supplements are readily available and safe interventions that may help prevent the development and progression of diabetic kidney disease. Preclinical and observational studies suggest that vitamin D suppresses the renin-angiotensin system, reduces renal inflammation and fibrosis, and exerts direct pro-survival effects on podocytes, while omega-3 fatty acids have potentially beneficial anti-inflammatory, antithrombotic, and vascular properties.


We performed a randomized clinical trial of 1,312 adults with type 2 diabetes to test whether supplementation with vitamin D3 or omega-3 fatty acids for five years prevents the development or progression of CKD. The study was completed as an ancillary study to the VITamin D and OmegA-3 TriaL (VITAL). In a 2-by-2 factorial design, participants were randomly assigned to vitamin D3 (2000 IU daily) or placebo and to omega-3 fatty acids (eicospentaenoic acid and docosahexaenoic acid, 1 g daily) or placebo. The primary outcome was change in glomerular filtration rate estimated from serum creatinine and cystatin C (eGFR) from baseline to year 5.


Baseline mean age was 67.6 (SD 6.9) years, 46% of participants were women, and 31% were racial or ethnic minorities. Baseline mean (SD) eGFR was 85.8 (22.1) mL/min/1.73m2, and mean change in eGFR from baseline to year 5 was -12.7 (SD 14.6) mL/min/1.73m2. There was no significant difference in change in eGFR comparing vitamin D3 to placebo (difference in change 0.8 (95% CI -0.8, 2.5) mL/min/1.73m2) or omega-3 fatty acids to placebo (difference in change 0.8 (95% CI -0.8, 2.4) mL/min/1.73m2). Null results were robust in analyses restricted to participants with complete data or to participants who were highly adherent to study medications. No significant difference was observed in secondary outcomes, including change in eGFR after 2 years of treatment, a composite outcome of loss of eGFR ≥40% from baseline or kidney failure (N=85 events), and change in urine albumin excretion.


Neither vitamin D nor omega-3 fatty acid supplementation reduced the development or progression of kidney disease among adults with type 2 diabetes.


  • NIDDK Support