Vitamin D Appears Linked With Risk of Skin Cancer, Although Relationship Complex
Study looked at vitamin D level in senior citizens with non-melanoma skin cancers
Aug. 15, 2011 Skin cancer, like most other cancers, plagues older people. Most seniors are well aware of the dangers of
the suns ultraviolet (UV) radiation for increasing the risk. A new study, however, finds that a high level of vitamin D also may increase the
risk of the non-melanoma skin cancers (NMSC).
The researchers caution, however, that factors such as ultraviolet (UV) radiation exposure may complicate the
relationship, according to the report published Online First by Archives of Dermatology, one of the JAMA/Archives journals.
The NMSC is the most common malignant tumor in the United States, and more cases of this cancer are diagnosed each year
than prostate, lung, colorectal, ovarian and breast cancer combined.
Prior research has found a clear association between radiation from the sun and skin cancer, with UV exposure believed to
be an important risk factor for NMSC. Although UV-B exposure causes the body to create vitamin D, the authors note that "evidence of the
association of vitamin D levels with skin cancer has been inconsistent," especially the relationship between NMSC and serum (circulating)
vitamin D levels.
Some research suggests vitamin D could reduce the risk for basal cell carcinoma (BCC), the most common subtype of NMSC.
Squamous cell carcinoma (SCC) is another form. The study sought to uncover more about the relationship between serum levels of vitamin D and
the risk of both BCC and SCC.
The study was conducted by Melody J. Eide, M.D., M.P.H., and colleagues from Henry Ford Hospital, Detroit. Those in the
study were among 3,223 white members of a health maintenance organization (HMO) who had a high probability of developing NMSC. Most of them
were senior citizens (mean age of 65.9) and the vast majority women - 2878 (89.3%).
Between January 1997 and December 2001, participants had sought counseling regarding osteoporosis or low-bone density;
the mean (average) length of follow-up was 9.8 years. Assessment included levels of serum 25-hydroxyvitamin D (25-OHD, an indicator of vitamin
D levels) as well as parathyroid hormone, creatinine and calcium levels. The HMO claims database was used to identify cases of NMSC, including
BCC and SCC.
More than two-thirds of participants (2,257) appeared to have insufficient levels of vitamin D.
Diagnoses of NMSC were made in 240 patients, including:
● 49 cases of squamous cell carcinoma (SCC),
● 163 cases of basal cell carcinoma (BCC) and
● 28 cases in which patients developed both forms.
Individuals who were not deficient in vitamin D appeared to have an increased risk of developing NMSC, even when
researchers considered other risk factors. The association between 25-OHD and NMSC appeared positive but not statistically significant for
tumors that developed on body parts not routinely exposed to UV radiation (such as the trunk, arms and legs).
The authors write that their findings contribute "to the limited and conflicting epidemiological investigation regarding
the relationship between vitamin D and NMSC."
Aside from the role of UV radiation, patients' historical vitamin D levels and consumption of vitamin D supplements could
be confounders. The authors suggest that more research into these relationships is needed "to further elucidate the highly complex
relationship between vitamin D and NMSC."
This study was supported in part by a Dermatology Foundation Career Development Award in Health Care Policy.
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