Antioxidant supplements do not appear to increase the risk of melanoma, according to a large, population-based study.
None of the exposure variables examined—overall antioxidant use, duration of use over the past 10 years, total dosage expressed in pill-years, or years of adult use during adulthood—correlated with melanoma risk in either men or women, said Dr. Maryam M. Asgari of Kaiser Permanente Northern California, Oakland, and her associates.
They undertook this study because the Supplementation in Vitamins and Mineral Antioxidants (SUVIMAX) study, a primary prevention trial published in 2007, found that daily oral supplementation with a combination of antioxidants raised the incidence of melanoma in women. The SUVIMAX findings were alarming, given that an estimated 48%–55% of American adults use supplements regularly, Dr. Asgari and her colleagues wrote.
They further examined the issue in a cohort of 69,671 adults who answered a 24-page questionnaire regarding health history, lifestyle factors, diet, supplement use, and cancer risk factors. They focused on the five antioxidants assessed in the SUVIMAX trial: vitamin C, vitamin E, zinc, beta carotene, and selenium.
Most of the study subjects (66%) were either current or former users of multivitamins. During 7 years of follow-up there were 461 incident cases of cutaneous melanoma.
Antioxidants were not associated with the disease. “Specifically, in the highest dose category of multivitamins … there was no increased risk of melanoma. Results were similar in men and women,” the investigators wrote (Arch. Dermatol. 2009;145:879–82).
Moreover, since many people take multivitamins plus additional beta carotene and selenium supplements, comparably high doses of these two nutrients were tested in a separate analysis. Again, no increased risk of melanoma was found and the results were the same for women and men.
It is likely that the SUVIMAX findings “could be explained by methodological shortcomings,” Dr. Asgari and her associates wrote.
In that study, subjects answered only a single question pertaining to their lifetime sun exposure, and “the analysis was based on only 16 cases” of melanoma. In addition, the incidence of melanoma in the SUVIMAX population was only 25 cases per 100,000 person-years—one-fifth the rate in the current study.
The work of Dr. Asgari and her associates was supported in part by the National Institute of Arthritis, Musculoskeletal and Skin Diseases and the National Cancer Institute. No financial conflicts of interest were reported.
