A new study published in the journal Cancer Epidemiology, Biomarkers & Prevention suggests that men with higher vitamin D status are less likely to die from prostate cancer than those with lower vitamin D status.
Research has shown that vitamin D may play a role in various types of cancer. One possible explanation for this repeated finding is that vitamin D helps regulate tumor growth, potentially reducing uncontrolled cell division. However, studies on vitamin D and prostate cancer have produced conflicting results. Most of these studies were relatively small with insufficient power, leaving the question of whether higher vitamin D status may improve prostate cancer survival unanswered.
In a recent study, researchers aimed to answer this question by assessing vitamin D status and prostate cancer survival in a cohort of 1,000 men with prostate cancer from the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study. The ATBC Study was a randomized controlled trial conducted to determine the effects of supplementation with alpha-tocopherol and beta-carotene on cancer incidence. All men smoked at least 5 cigarettes per day and were between 50-69 years old at the time of enrollment. The men supplemented for 5-8 years with the RCT coming to an end in 1993. The follow-up continued through the Finnish Cancer Registry and the Register of Causes of Death through the end of 2012.
The researchers compared vitamin D levels at baseline to mortality rates among the 1,000 men. On a side note, the vitamin D levels were measured by our friends, Heartland Assays, who also measure the Vitamin D Council’s in-home vitamin D test kit.
Here is what the researchers found:
- After adjusting for age at diagnosis, men with prostate cancer who had higher vitamin D status were 31% less likely to die than men with the lowest vitamin D status (p = 0.003).
- After adjusting for age, cigarettes smoked daily, physical activity and family history of prostate cancer, those with higher vitamin D status were 28% less likely to die than men with the lowest vitamin D status (p = 0.006).
- Among men who lived less than 3.3 years after being diagnosed, vitamin D status was unrelated to mortality (p = 0.53).
- Among men who lived 3.3 years or more, a higher vitamin D status was associated with a 47% reduced odds of mortality (p = 0.0002).
The researchers concluded,
“In this population of men diagnosed with prostate cancer, higher serum 25(OH)D prior to diagnosis was associated with improved prostate cancer survival.”
“Our findings that higher 25(OH)D reduces the most clinically relevant prostate cancer outcome, disease-specific mortality, if true, could have important public health implications, including whether vitamin D supplementation should be considered for men diagnosed with prostate cancer.”
The study possessed several strengths. The large sample size with a relatively large number of prostate cancer deaths allows the researchers to better detect any relationships that exist between vitamin D status and mortality. They also obtained detailed information on potential factors that could skew the results and adjusted the results accordingly. On the other hand, the study only measured vitamin D status once (at baseline), meaning that the men’s vitamin D status may have easily changed over the course of the study.
The researchers call for clinical trials to assess the efficacy of vitamin D supplementation among prostate cancer patients.
Tovey, A. & Cannell, JJ. Recent study finds high vitamin D levels associated with longer prostate cancer survival. The Vitamin D Council Blog & Newsletter, January 2016.