Regular Vitamin D Supplements May Lower Melanoma Risk
Individuals who regularly take vitamin D supplements are significantly less likely to have a history of malignant melanoma or any type of skin cancers than non-users, say Finnish investigators. They also found a trend for benefit with occasional use.
The study, published December 28 in Melanoma Research, involved almost 500 individuals attending a dermatology clinic who reported on their use of vitamin D supplements.
Regular users had a significant 55% reduction in the odds of having a past or present melanoma diagnosis, while occasional use was associated with a nonsignificant 46% reduction. The reduction was similar for all skin cancer types.
However, senior author Ilkka T. Harvima, MD, PhD, Department of Dermatology, University of Eastern Finland and Kuopio University Hospital, Kuopio, Finland, warned there are limitations to their study.
Despite controlling for several possible confounding factors, "it is still possible that some other, yet unidentified or untested, factors can still confound the present result," he said.
Even if the link were to be proven, "the question about the optimal dose of oral vitamin D in order to for it to have beneficial effects remains to be answered," he commented.
"Until we know more, national intake recommendations should be followed."
Melanoma on the Increase
The incidence of cutaneous malignant melanoma and other skin cancers has been increasingly steadily in Western populations, particularly in immunosuppressed individuals, the authors point out, and they attribute the rise to an increased exposure to ultraviolet radiation.
While ultraviolet radiation exposure is a well-known risk factor, "the other side of the coin is that public sun protection campaigns have led to alerts that insufficient sun exposure is a significant public health problem, resulting in insufficient vitamin D status."
For their study, the team reviewed the records of 498 patients aged 21-79 years at a dermatology outpatient clinic who were deemed by an experienced dermatologist to be at risk of any type of skin cancer.
Among these patients, 295 individuals had a history of past or present cutaneous malignancy, with 100 diagnosed with melanoma, 213 with basal cell carcinoma, and 41 with squamous cell carcinoma. A further 70 subjects had cancer elsewhere, including breast, prostate, kidney, bladder, intestine and blood cancers.
A subgroup of 96 patients were immunocompromised and were considered separately.