New research published in the August 15th issue of the Archives of Dermatology stated the higher a person's vitamin D levels, the higher the risk of non-melanoma skin cancer, such as basal cell carcinoma and squamous cell carcinoma. Since ultraviolet (UV) radiation exposure is necessary for vitamin D production in the body, it may suggest that people with more sun exposure tend to develop more non-melanoma skin cancers. It's unclear whether it's the damage from UV rays that accounts for the risk, or rising vitamin D levels that accompany exposure to the rays.
This information rivals another more recognized study suggesting that higher vitamin D levels might actually protect against skin cancer. This could be because vitamin D may inhibit a pathway involved in cancer, said Dr. Melody Eide, a dermatologist with Henry Ford Hospital in Detroit and lead author of the current study.
Eide and colleagues based their findings on 3,223 mostly female, white patients in a Detroit health maintenance organization who had visited a doctor either because they had osteoporosis or low bone density. Many more patients (2,257) had too-low levels of vitamin D than had adequate levels (966). Over a follow-up period of almost 10 years, 163 participants developed basal cell carcinoma, 49 developed squamous cell carcinoma, and 28 developed both.
It's a triangular relationship between UV light with the production of Vitamin D and the induction of skin cancer," Eide said. "That makes it difficult to know." The study didn't take into account lifetime sun exposure, family history of skin cancer, vitamin Dsupplementation, exercise, smoking or several other factors that might have influenced the outcome of the study. In addition, the study authors noted that it was "highly likely" that the participants' exposure to sunlight might have skewed the results. "We need some measure of lifetime cumulative UV exposure, which is very difficult to measure," Eide said. "We tend to move around a lot; people go on vacations. There could be critical windows during our life."
