South Asia Mail

Association Found Between Vitamin D Levels And Risk Of Skin Cancer

A new report by JAMA, published Online First by Archives of Dermatology, has found an association between a person's vitamin D levels and risk of non-melanoma skin cancer (NMSC). The report observed that when an individual's vitamin D level increases, their risk of developing NMSC seems to increase too. They noted that factors such as UV radiation exposure could complicate the relationship though.

The report's background information showed that the most common form of malignant tumor in the US is NMSC. The total number of NMSC cases being diagnosed each year exceed the number of all lung, ovarian, breast and prostate cancer cases combined.

A strong link has been found in previous research between radiation from the sun and skin cancer, with UV exposure as one of the main risk factors for NMSC. The authors noted that although UV-B exposure results in the body creating vitamin D, the "evidence of the association of vitamin D levels with skin cancer has been inconsistent," in particular the association between serum (circulating) vitamin D levels and NMSC. Previous research has suggested that vitamin D could lower the risk for common subtypes of NMSC, such as basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Given the uncertainty regarding the association between serum levels of vitamin D and the risk of the two subtypes of NMSC, the authors sought to understand more about the relationship.

A study was made on 3,223 white members of a health maintenance organization (HMO) with high risk for developing NMSC. The study was conducted by Melody J. Eide, M.D., M.P.H., and colleagues from Henry Ford Hospital, Detroit. Participants in the study had looked for counseling concerning osteoporosis or low bone density between January 1997 and December 2001, and averaged a 9.8 year length of follow up. Levels of serum 25-hydroxyvitamin D (25-OHD, an indicator of vitamin D levels), calcium, parathyroid hormone, and creatinine were included in the assessment. To pinpoint cases of NMSC and the subtypes (SCC and BCC) the HMO claims database was used.

A total of 2,257 of the members, over two thirds, had insufficient vitamin D levels. There were 240 patients that were diagnosed with NMSC, of which 163 had BCC, 49 had SCC, and 28 had both forms of the subtype. It was observed, even considering other risk factors, that the risk of developing NMSC seemed to increase among people whose vitamin D levels were sufficient. There was certainly a positive association between 25-OHD and NMSC, although it was still statistically insignificant for tumors developing on body parts with limited UV radiation exposure, such as the arms and legs.

The authors said that:

"(these findings are a valuable contribution) to the limited and conflicting epidemiological investigation regarding the relationship between vitamin D and NMSC." They also suggested that more research into the matter is necessary "to further elucidate the highly complex relationship between vitamin D and NMSC."