Prostate cancer: chance of survival is lower when vitamin D is low

Prostate cancer: less chance of survival if vitamin D is low

There appears to be an association between high levels of vitamin D in the blood and an increased likelihood of surviving prostate cancer. Men with a higher concentration of the vitamin, measured before the disease was diagnosed, show a 28 percent lower risk of dying, compared with those with lower concentrations.

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 tumors

Vitamin D is a molecule that acts as a hormone, and it is essential for ensuring good calcium absorption in the gut and ensuring proper mineralization of bone. Vitamin D intake is possible either through foods consumed in the diet or through sun exposure; in both cases it occurs in a biologically inactive form, and its activation involves certain reactions in the body. Among foods, vitamin D is mainly found incod liver oil, some fish such as mackerel, salmon, trout, sardines, and herring, cow's and goat's milk, egg yolk, chicken liver, offal, and wheat germ. The main circulating form of vitamin D is 25-hydroxyvitamin D (25(OH)D), which is converted to 1-25-dihydroxyvitamin D. 

Although the latter is the biologically active form, it is not used as an indicator of an individual's vitamin status because of its short ability to remain in circulation. In contrast, 25-hydroxyvitamin D, with a half-life of about 2 weeks, is used to estimate vitamin D levels in a person.The normal range in an adult of 25(OH)D is between 30 and 80 ng /mL In addition to its known role on bone metabolism, vitamin D also has important functions in regulating the immune system, and in preventing diseases such as diabetes, autoimmune, infectious, and cardiovascular diseases. 

It has been hypothesized that vitamin D may also counteract many types of malignancies including prostate cancer, although studies on this are still few and with conflicting results.

More 25(OH)D more cancer survival

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

Each man's blood 25-(OH) D concentrations were known, and specific statistical analysis showed that those whose levels of this form of the vitamin were measured highest had a 28 percent lower risk of dying from prostate cancer than those with the lowest values. The association appeared to be independent of tumor grade at the time of diagnosis, and was stronger among men who had survived for a greater number of years. 

These data were found to be very promising, although contrasted with those of other papers that found no association between vitamin D levels and prostate cancer mortality. According to Mondul, previous studies had considered too small a number of subjects; in addition, other research had either measured vitamin D levels at the time of disease diagnosis or included men with advanced cancers, ignoring the fact that cancer and metastasis can affect vitamin status.

The steps that led the researchers to the conclusions 

The study began in 1985 and involved about 29,000 men aged 50 to 69 years with no particular health problems. Each subject's serum levels of 25-hydroxyvitamin D and other factors were measured; in addition, specific questionnaires regarding diet and medical history were completed by all participants at the beginning of the research. After 23 years, 1,000 participants were diagnosed with prostate cancer, and 363 of them died from the disease. The men with higher 25(OH)D levels tended to be older at the time of blood collection and at the time of prostate cancer diagnosis, and were more physically active than the others; they also consumed more vitamin D through both diet and supplements.

Vitamin D supplementation to live longer?

Their results show that men with prostate cancer who showed higher 25(OH)D in serum were less likely to die from the disease than men with lower serum levels. According to the researchers who conducted the study, such a clinically relevant finding, i.e., reduced mortality due to the disease, if confirmed, could have important implications for public health, including, consider vitamin D supplementation in men with prostate cancer.  

Source: Alison M. Mondul1, 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..