Most readers have heard the terms non-Hodgkin’s lymphoma (NHL) and Hodgkin’s lymphoma (HL). Lymphoma is a cancer of the lymphocytes, which may grow faster than normal cells or live longer than normal cells, thus accumulating into masses, often in the lymph nodes.
Did you know there are 61 types of NHL and 6 types of HL? Hodgkin’s lymphoma is named after Dr. Thomas Hodgkin, the English pathologist who first described lymphoma. HL has a particular type of cell (Reed-Sternberg) and all the 61 types of lymphoma without that cell type are called NHL.
Lymphoma presents as swelling in the lymph nodes. It may also present with non-specific symptoms, such as fever, weight loss and night sweats, which, if they persist, means lymphoma needs to be ruled out. Treatment may involve chemotherapy, radiotherapy and even bone marrow transplantation in some cases. Lymphoma is curable depending on the cellular structure, the type, and the stage of the disease
It is important to remember, in any discussion of cancer and vitamin D, the best we can hope for is that adequate vitamin D levels will reduce, not eliminate, the risk of some forms of cancer, especially colon cancer. While we are on the topic of lymphoma, one of the most famous types of cancer is Burkitt’s lymphoma, which was first described in equatorial Africa, where it is still the most common type of cancer seen in children. It is caused by impaired immunity, usually from malaria, combined with infection by the Epstein Barr virus. Vitamin D deficiency appears to play little role in Burkitt’s lymphoma, as it may not be involved in other cancer types. So even if you take 5,000 IU/day, you can still get cancer.
Doctor Marina van Leeuwen and colleagues out of the University of New South Wales in Australia have just recently published a study on lymphoma and latitude. They gathered enough data to analyze lymphoma and latitude by subtypes of lymphomas.
van Leeuwen MT, Turner JJ, Falster MO, Meagher NS, Joske DJ, Grulich AE, Giles GG, Vajdic CM. Latitude gradients for lymphoid neoplasm subtypes in Australia support an association with ultraviolet radiation exposure. Int J Cancer. 2013 Feb 5.
First of all, the existing data on latitude and lymphoma are contradictory, with some studies in Europe even showing living closer to the equator being associated with more lymphoma. However, Europe has an unusual gradient in vitamin D levels, thought to be secondary to high fish consumption in Norwegian countries. On the contrary, four studies from the USA show the closer one lives to the equator, the less the risk of getting or dying from lymphoma.
One study showed an inverse association for history of sun and sunbed use and lymphoma, the more sunshine or the more sunbed use, the less the risk of lymphoma.
In Doctor van Leeuwen’s study, they studied all the cases of lymphoma in Australia during the years 2002 to 2006. They included a total of more than 30,000 cases of non-Hodgkin’s lymphoma and around 2,500 cases of Hodgkin’s lymphoma. Around 29°S represents the highest level of UV radiation in Australia, and the lowest UVR in Australia is around 37°S latitude. They found that increasing latitude was associated with higher rates of both NHL and HL, with the gradient the strongest for HL; its incidence was around 60% higher for the most poleward latitude in Australia, compared to the most equatorial latitude.
When they looked at some of the 67 different types of lymphoma, those lymphoma types that arise after lymphocytes have been exposed to a known carcinogen, usually a virus, or that arise from immune dysregulation, showed the most decreased risk with decreasing latitude. Thus, their findings give better insight how latitude, putative sun exposure and possibly vitamin D may affect some types of lymphoma, but not others. It also supplies a possible explanation why some studies show a correlation between latitude and lymphoma incidence, and some do not.
The authors concluded,
“In conclusion, these data provide support for a possible protective effect of UVR exposure on the risk of several subtypes of lymphoid neoplasm. The observation that this effect was confined mostly to subtypes with an infectious etiology or an association with immune dysregulation is novel and warrants replication. A role for vitamin D-mediated control in the pathogenesis of these lymphoid neoplasms is suggested.”