Hodgkin’s Lymphoma: An Environmental Scan
Table of Contents
3.14.3 Vitamin D
It is well understood in the literature the impact low vitamin D levels have on overall health and specifically how low(er) levels lead to an increased susceptibility to infections. Furthermore, various epidemiological studies and observations have hypothesized a significant association among vitamin D sufficiency and the reduction of risk associated with various forms of cancer. Vitamin D levels are associated with both the incidence and new cases of cancer along with the morbidity of cancer as a whole (Kulie et al. 2009).
The vitamin D Council reports the association among 15 cancers and vitamin D deficiency (Hodgkin’s lymphoma, non-Hodgkin’s lymphoma, colon, esophageal, gallbladder, gastric, pancreatic, rectal, small intestinal, bladder, kidney, prostate, breast, endometrial and ovarian cancers). Dr. Jacob Cannell is a champion physician in the area of vitamin D and heads the vitamin D Council. Recent recommendations during a symposium held in 2008 included a warning message that the recommended vitamin D levels are too low, along with an important key point about having serum vitamin D levels tested, which is an extremely inexpensive blood test that renders valuable information about overall health and potential risk if levels are found deficient. This may prove particularly important among adolescents and young adults and is paramount when considering the primary prevention of cancer (Cedric F Garland et al. 2009).
In a large portion of the world, individuals experience a seasonal variation in vitamin D levels that are the highest between July and September compared to very low levels in winter months. Interestingly, a Norwegian study published in 2005 in the British Journal of Cancer sought to examine the relationship between the seasonal variation in vitamin D levels and prognostic factors among HL patients. As such, they looked at what season in the year a patient was diagnosed and began treatment for HL and their corresponding vitamin D levels during the same time period. As previously established for breast, colon and prostate cancer, this study also found a significant improvement in the prognosis of HL related to seasonal variations.
Among patients who were younger than 30 years of age and diagnosed in the fall, the survival rates were 60% higher (Porojnicu et al. 2005). Although other explanations for the findings were considered such as better overall health status right after the summer months and because of vacations along with possible confounding issues due to an increased intake of fresh foods during the same time period which would increase antioxidants, researchers concluded such explanations did not impact the study results. In opposition to the positive findings surrounding vitamin D, the Cohort Consortium Vitamin D Polling Project of Rarer Cancers measured blood levels of 25-hydroxy vitamin D, which is the primary form of vitamin D and did not find any evidence to suggest higher circulating vitamin D levels were protective for endometrial, esophageal, stomach, ovarian, pancreatic, kidney and non-Hodgkin’s lymphoma. In fact, among study participants, higher circulating vitamin D appeared to have an increased risk associated with pancreatic cancer.
Beyond the potential benefits in treatment among individuals with cancer, vitamin D therapy holds promise for prevention. There are particular methodological issues associated with this body of research that include small sample sizes of patients and a small representation of studies focused on rare cancers. Overall, more work is necessary to specifically understand the relationship between vitamin D levels and the prevention or recurrence of cancer. (A substantial list of research in the area of vitamin D and cancer is available at http://www.vitamindcouncil.org/researchCancer.shtml)