Prostate Cancer: Chances of Survival Are Lower When Vitamin D Is Low

Prostate Cancer: Lower Survival Chances if Vitamin D is Low

There appears to be an association between higher blood levels of vitamin D and an increased likelihood of surviving prostate cancer. Men with higher concentrations of vitamin D measured before their diagnosis show a 28% lower risk of dying from the disease compared to those with lower levels.

This is suggested by a study published in the journal Cancer Epidemiology, Biomarkers & Prevention, conducted by researchers at the National Cancer Institute in Bethesda, Maryland (USA).

Vitamin D and Cancer

Vitamin D is a molecule that acts as a hormone and is essential for ensuring proper calcium absorption in the intestines and correct bone mineralization. Vitamin D intake can occur through diet or sun exposure; in both cases, it is biologically inactive and requires activation through processes in the body. Dietary vitamin D is mainly found in cod liver oil, certain fish such as mackerel, salmon, trout, sardines, herrings, cow and goat milk, egg yolks, chicken liver, offal, and wheat germ. The primary circulating form of vitamin D is 25-hydroxyvitamin D (25 (OH) D), which is converted into 1,25-dihydroxyvitamin D.

Although the latter is the biologically active form, it is not used as an indicator of vitamin status due to its short circulation time. Conversely, 25-hydroxyvitamin D, with a half-life of about two weeks, is used to estimate vitamin D levels in a person. The normal range of 25 (OH) D in adults is between 30 and 80 ng/mL. Besides its known role in bone metabolism, vitamin D also plays important roles in regulating the immune system and preventing diseases such as diabetes, autoimmune, infectious, and cardiovascular diseases.

It has been hypothesized that vitamin D may also counteract many types of cancers, including prostate cancer, although studies on this are still limited and results are mixed.

More 25 (OH) D, Better Cancer Survival

During the study, led by Alison Mondul from the Department of Health and Human Services, data from 1,000 men who had participated in a large study while healthy and were later diagnosed with prostate cancer were analyzed.

Each man’s blood concentration of 25-(OH) D was known, and specific statistical analyses showed that those with higher levels of this vitamin form had a 28% lower risk of dying from prostate cancer compared to those with lower values. The association appeared independent of tumor grade at diagnosis and was stronger among men who survived longer.

These data are promising, although contrasting with other studies that found no association between vitamin D levels and prostate cancer mortality. According to Mondul, previous studies included too few subjects, measured vitamin D levels only at diagnosis, or included men with advanced tumors, ignoring that cancer and metastases can influence vitamin status.

Steps Leading Researchers to Their Conclusions

The study began in 1985 and involved about 29,000 men aged 50 to 69 without major health issues. Serum levels of 25-hydroxyvitamin D and other factors were measured, and diet and medical history questionnaires were completed at baseline. After 23 years, 1,000 participants were diagnosed with prostate cancer, and 363 of them died from the disease. Men with higher 25 (OH) D levels tended to be older at blood collection and cancer diagnosis, were more physically active, and consumed more vitamin D through diet and supplements.

Vitamin D Supplementation to Live Longer?

The results show that men with prostate cancer who had higher serum 25 (OH) D levels were less likely to die from the disease compared to men with lower serum levels. According to the researchers, this clinically relevant finding—reduced mortality from the disease—if confirmed, could have important public health implications, including considering vitamin D supplementation for men affected by prostate cancer.

Source: Alison M. Mondul, Stephanie J. Weinstein, Kristin A. Moy, Satu Mannisto, and Demetrius Albanes. Circulating 25-hydroxyvitamin D and prostate cancer survival. Cancer Epidemiology, Biomarkers & Prevention Published OnlineFirst January 25, 2016