Studies Link Higher Vitamin D Levels With Improved Cancer Prognosis

Two recently published clinical studies demonstrated a strong association between higher levels of vitamin D and improved outcomes among patients with various cancers.

In one study, researchers from the Institute for Nutritional Sciences at the Shanghai Institutes for Biological Sciences in China examined circulating 25-hydroxyvitamin D [25(OH)D] levels among 17,332 patients with different tumor types across 25 studies. Vitamin levels were measured at or near diagnosis.¹

Overall, the meta-analysis showed that a 10-nmol/L increase in circulating 25(OH)D levels was linked to a 4% improvement in overall survival (OS; HR = 0.96; 95% CI, 0.95-0.97).

The strongest association between vitamin D levels and improved OS was observed in patients with colorectal cancer, breast cancer, and lymphoma. In these groups, the pooled HR for OS for the highest versus the lowest quartile of circulating 25(OH)D levels was 0.55, 0.63, and 0.48, respectively. A positive correlation was also observed in patients with lung cancer, gastric cancer, prostate cancer, leukemia, melanoma, and Merkel cell carcinoma; however, the connection was not as strong.

“Considering that vitamin D deficiency is a widespread issue all over the world, it is important to ensure that everyone has sufficient levels of this important nutrient,” one of the study authors, Hui Wang, MD, PhD, a professor at the Institute for Nutritional Sciences, said in statement. “Physicians need to pay close attention to vitamin D levels in people who have been diagnosed with cancer.”

In a second study, researchers found that men at high risk of prostate cancer who had a vitamin D deficiency are more likely to have aggressive disease at diagnosis.²

The researchers examined serum 25(OH)D levels in 667 high-risk men who were screened for vitamin D deficiency prior to receiving their first prostate biopsy. The men, aged 40 to 79 years, had elevated PSA levels and other prostate cancer risk factors.

“This is the first study to look at vitamin D deficiency and biopsy outcomes in men at high risk of prostate cancer,” said senior author Rick Kittles, associate professor in the Department of Medicine at the University of Illinois at Chicago. “Previous studies focused on vitamin D levels in men either with or without prostate cancer.”

Among the study population, African-American men with 25(OH)D <20 ng/mL had 2.43-fold increased odds of receiving a prostate cancer diagnosis of any stage (P = .01). Additionally, African-American men with 25(OH)D <12 ng/mL were 4.89 times more likely to have a Gleason score ≥4+4 (P = .006) and 4.22 times more likely to have a tumor stage ≥cT2b (P = .003).

European-American men with 25(OH)D <12 ng/mL were 3.66 times more likely to have a Gleason score ≥4+4 (P = .008) and 2.42 times more likely to have a tumor stage ≥cT2b (P = .008).

The increased odds for aggressive disease among patients with vitamin D deficiency were established after adjusting for potential confounding factors, including obesity, smoking, family history, diet, and calcium intake.

“Vitamin D deficiency could be a biomar ker of advanced prostate tumor progression in large segments of the general population,” said leader author Adam B. Murphy, MD, assistant professor in Urology at Northwestern University Feinberg School of Medicine, in a statement. “More research is needed, but it would be wise for men to be screened for vitamin D deficiency and treated.”

References

1. Li M, Chen P, Li J, Chu R, et al. Review: the impacts of Circulating 25-hydroxyvitamin D levels on cancer patient outcomes: a systematic review and meta-analysis [published online April 29, 2014]. J Clin Endocrinol Metab. doi:10.1210/ jc.2013-4320.
2. Murphy AB, Nyame Y, Martin IK, et al. Vitamin D deficiency predicts prostate biopsy outcomes. Clin Cancer Res. 2014;20(9):2289-2299.