Vitamin D Has No Effect on Cancer Risk, Study Finds
High-dose vitamin D supplementation likely does not help lower cancer risk, according to new findings.
Researchers arrived at this conclusion following a post-hoc analysis of 5108 participants from the Vitamin D Assessment Randomized Clinical Trial.
IF YOU LIKED THIS, READ MORE...
What Do You Need to Know About Vitamin D and Diabetes?
Vitamin D Supplementation: Could Infants Benefit from a Higher Dosage?
All participants included in the trial were aged 50 to 84 years and were recruited from family practices and community groups in Auckland, New Zealand.
Each participant was randomly assigned to receive oral vitamin D3 at an initial bolus dose of 200,000 IU followed by a dose of 100,000 IU each month (n = 2558) or placebo (n = 2552) for a median of 3.3 years.
The mean de-seasonalized 25-hydroxyvitamin D concentration at baseline was 26.5 ng/mL.
The primary outcome of the analysis was defined as the number of all primary invasive and in situ malignant neoplasms diagnosed from baseline until medication cessation on July 31, 2015. Nonmelanoma skin cancers were not included.
Ultimately, the results of the study showed that high-dose vitamin D supplementation was not associated with a decreased cancer risk compared with placebo. A total of 328 cases of cancer that met the primary outcome criteria occurred in 165 (6.5%) of 2558 vitamin-D–treated participants vs 163 (6.4%) of placebo-treated participants.
The mean 25-hydroxyvitamin D concentration at follow-up was consistently more than 20 ng/mL higher in patients receiving vitamin D supplementation vs those receiving placebo.
“High-dose vitamin D supplementation prescribed monthly for up to 4 years without calcium may not prevent cancer,” the researchers concluded. “This study suggests that daily or weekly dosing for a longer period may require further study.”
—Christina Vogt
Reference:
Scragg R, Khaw KT, Toop L, et al. Monthly high-dose vitamin D supplementation and cancer risk: a post hoc analysis of the Vitamin D Assessment Randomized Clinical Trial [Published online July 19, 2018]. JAMA Oncol. doi:10.1001/jamaoncol.2018.2178.