In individuals without cancer, vitamin D supplementation may decrease the risk of developing advanced cancer, especially for those with a normal body mass index (BMI), according to a recent analysis of a phase 3 trial.
"Vitamin D may decrease tumor invasiveness and propensity to metastasize, leading to reduced cancer mortality," write the investigators, led by first author Paulette D. Chandler, MD, MPH, Assistant Professor of Medicine at Harvard Medical School. "Vitamin D may have a role in reducing more advanced or fatal cancers, but this specific question has not been previously addressed in randomized trials."
In an analysis of the phase 3 VITAL trial, Dr. Chandler and colleagues investigated the potential of vitamin D to reduce the risk of developing advanced cancer, defined as cancer that is metastatic or fatal. The trial enrolled 25,871 adult participants with no diagnosis or history of cancer or cardiovascular disease at baseline. Participants were randomized to receive vitamin D, omega-3 fatty acids, both regimens, or placebo. Vitamin D supplements were administered in a dose of 2,000 IU per day for approximately five years. The primary end points of the analysis were the incidence of advanced cancer and time to cancer diagnosis from baseline, with a secondary end point of BMI assessment.
After a median intervention period of 5.3 years, 1,617 individuals in the overall study population had been diagnosed with advanced cancer, with the most common types being breast, prostate, colorectal, or lung cancer. Participants taking vitamin D supplements experienced a lower incidence of advanced cancer compared with those taking placebo (1.7% vs 2.1%), with a hazard ratio of 0.83. Individuals with a normal BMI, one under 25, had a significant decrease in advanced cancer incidence, with a hazard ratio of 0.62; however, participants who were classified as overweight or obese did not experience a significant reduction in risk, with a hazard ratio of 0.89 for those with a BMI of 25-30 and a hazard ratio of 1.05 for those with a BMI of 30 or greater.
"This randomized clinical trial of daily high-dose vitamin D supplementation for five years reduced the incidence of advanced (metastatic or fatal) cancer in the overall cohort of adults without a diagnosis of cancer at baseline, with strongest risk reduction in individuals with normal weight," conclude Dr. Chandler and colleagues in their publication in JAMA Network Open. "Additional randomized trials focusing on cancer patients should be considered, as well as investigations of differential benefit by BMI."
For More Information
Chandler PD, Chen WY, Ajala ON, et al (2020). Effect of vitamin D3 supplements on development of advanced cancer: a secondary analysis of the VITAL randomized clinical trial. JAMA Netw Open, 3(11):e2025850. DOI:10.1001/jamanetworkopen.2020.25850
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